Potassium nitrate(KNO_(3))promotes adventitious root(AR)formation in apple stem cuttings.However,evidence for the possible involvement of cytokinin(CK)in KNO_(3)-mediated AR formation in apples is still lacking.In thi...Potassium nitrate(KNO_(3))promotes adventitious root(AR)formation in apple stem cuttings.However,evidence for the possible involvement of cytokinin(CK)in KNO_(3)-mediated AR formation in apples is still lacking.In this study,we cultured GL-3 apple microshoots in different treatment combinations.While the T1(KNO_(3)9.4 mmol L^(-1)+6-benzyl adenine(6-BA)2.22μmol L^(-1))and T3(6-BA 2.22μmol L^(-1))treatments completely inhibited AR formation,the control,T2(KNO_(3)9.4 mmol L^(-1)),and T4(KNO_(3)9.4 mmol L^(-1)+lovastatin(Lov)1.24μmol L^(-1))treatments developed ARs.However,T4-treated microshoots developed fewer and shorter ARs,indicating that optimum CK synthesis is needed for normal AR growth.This also suggests that these fewer and shorter ARs developed because of the presence of KNO_(3) in the same medium.The anatomy of the stem basal part indicated that the inhibition of CK biosynthesis delayed AR primordia formation.The endogenous levels of indole-3-acetic acid(IAA)and zeatin riboside(ZR)were higher in T2-treated microshoots,while the abscisic acid(ABA),gibberellic acid 3(GA_(3)),and brassinosteroid(BR)levels were higher in T4-treated microshoots.The expression levels of MdNRT1.1and MdNRT2.1 were higher in T2-treated microshoots at 3 and 8 days,while MdRR2 and MdCKX5 were higher at 8 and 16 days,respectively.Furthermore,higher IAA levels increased MdWOX11 expression,which in turn increased MdLBD16 and MdLBD29 expression in response to T2.The combined expression of these genes stimulated adventitious rooting by upregulating cell cycle-related genes(MdCYCD1;1 and MdCYCD3;1)in response to T2 treatment.This study shows that specific genes and hormonal pathways contribute to KNO_(3)-CK-mediated adventitious rooting in apples.展开更多
Root regeneration is an important factor influencing the healing rate of graft union and the survival of double-root-cutting grafting.To date,little information is available on how to enhance root regeneration of root...Root regeneration is an important factor influencing the healing rate of graft union and the survival of double-root-cutting grafting.To date,little information is available on how to enhance root regeneration of rootstock in grafted watermelon(Citrullus lanatus)seedlings.In this study,the effects of different light treatments on root regeneration were determined.This revealed that addition of far-red light(Fr)could significantly expedite root formation in the rootstock.Moreover,the results of transcriptome analysis revealed that plant hormone pathway and auxinrelated genes were greatly induced by Fr,especially for auxin-response proteins(including CmIAA11,CmIAA17,and CmAUX28),Small auxinup RNA genes(including CmSAUR20 and CmSAUR50)and the auxin efflux transporter(CmPIN3).In addition,the expression of Phytochrome Interacting Factor(PIFs),such as CmPIF1,CmPIF3 and CmPIF7,was remarkably increased by Fr.These genes may act together to activate auxinrelated pathways under Fr treatment.Based on the results of HPLC-MS/MS analysis,the concentrations of different auxin-types in adventitious root were significantly influenced by Fr.Furthermore,the better growth of rootstock root displayed superior vasculature transport activity of the graft union with Fr treatment,which was determined by the acid magenta dyeing experiment.Therefore,all the results suggested that Fr could induce AR formation in rootstocks,which may be associated with the auxin accumulation by regulating the transcriptional level of auxinrelated and PIF genes.The findings of this study demonstrated a practicable way to shorten the healing period of graftings and improve the quality of grafted watermelon seedlings,which will provide a theoretical basis for the speeding development of industrialized seedlings production.展开更多
Inducing adventitious root(AR)formation in mature walnut species(Juglans L.)is challenging.However,the AR formation of mature trees can be improved by rejuvenation.In rejuvenated cuttings,exogenous indole-3-butyric ac...Inducing adventitious root(AR)formation in mature walnut species(Juglans L.)is challenging.However,the AR formation of mature trees can be improved by rejuvenation.In rejuvenated cuttings,exogenous indole-3-butyric acid(IBA)is essential for AR formation,and the underlying mechanism is still not well understood.Therefore,we utilized transcriptome sequencing to investigate the mechanism of IBA-induced AR formation.Our results revealed that,in comparison to the control group,IBA treatment(9 mmol·L^(-1))significantly increased the endogenous indole-3-acetic acid(IAA)content,leading to an enhanced rooting rate.We performed RNA sequencing to identify differentially expressed genes(DEGs)between the IBA-treated and control(CK)groups at 1,2,3,and 5 days after cutting(DAC).The results showed that,compared to the control cuttings,there were 1539,889,785,and 984 up-regulated genes and 2791,2936,3017,and 1752 down-regulated genes,at 1,2,3,and 5 DAC,respectively.Analysis of RNA-seq data revealed that G-type ATP-binding cassette 36/37(ABCG36/37)and ATP-binding cassette subfamily D 1(ABCD1),associated with IBA transport,were down-regulated in the rejuvenation cuttings.In contrast,PIN-FORMED(PIN)and PINOID(PID),associated with auxin efflux,were up-regulated.We identified 49 auxin/indole-3-acetic acid(AUX/IAA)-encoding genes,including IAA1,IAA3,IAA5,IAA6,IAA8,IAA11,IAA12,IAA19,and IAA20,which were up-regulated at 1-5 DAC in the rejuvenated cuttings.This study highlights that the overexpression of JrWOX5/11 in poplar significantly enhance AR growth,as evidenced by increased root length,surface area,volume,and quantity.Moreover,the co-expression network analysis involving JrWOX11 and JrWOX5 in walnut cuttings elucidates complex genetic interactions,underscoring their pivotal role in the formation of AR.Our data supported the following molecular mechanism of IBA-induced adventitious root formation.Firstly,IBA is converted to free IAA in peroxisomes.Then,the highly concentrated IAA in the procambium and parenchyma cells induces WUSCHEL-related homeobox 11(WOX11)expression at two days.Finally,WOX11 acts redundantly to up-regulate WOX5,initiating the development of root primordia cells.展开更多
Adventitious root formation is a bottleneck during vegetative proliferation.Potassium(K^(+))is an essential macronutrient for plants.K^(+)accumulation from the soil and its distribution to the different plant organs i...Adventitious root formation is a bottleneck during vegetative proliferation.Potassium(K^(+))is an essential macronutrient for plants.K^(+)accumulation from the soil and its distribution to the different plant organs is mediated by K^(+)transporters named K^(+)transporter(KT),K^(+)uptake(KUP),or high-affinity K^(+)(HAK).This study aimed to identify members of the HAK gene family in apples and to characterize the effects of K^(+)supply on adventitious root formation and on the expression of HAK genes and the genes that putatively control auxin transport,signaling,and cell fate during adventitious root formation.In this study,34 HAK genes(MdHAKs)were identified in the apple(Malus×domestica‘Golden Delicious’)genome.A phylogenetic analysis divided MdHAKs into four clusters(Ⅰ,Ⅱ,Ⅲ,andⅣ),comprising 16,1,4,and 13 genes,respectively.The syntenic relationships revealed that 62.5%of the total MdHAK genes arise from genomic duplication events.Chromosome location,domain structure,motif analysis,and physico-chemical characteristics were subsequently investigated.Furthermore,the application of K^(+)indicated the emergence of adventitious roots at 8 d and produced more adventitious roots at 16 d than the K^(+)-free control(CK)treatment.In addition,various MdHAKs showed root-specific expression in B9 apple rootstock stem cuttings and enhanced expression during the initiation and emergence stages of adventitious root formation in response to K^(+)treatment.Additionally,K^(+)treatment enhanced the expression levels of MdPIN1,MdPIN2,and MdAUX1.Further data indicated that a higher expression of MdWOX11,MdLBD16,and MdLBD29 and of cell cycle-related genes contributed to the auxin-stimulated adventitious root formation in response to K^(+).展开更多
Plant regeneration is a self-repair of the plant body in response to adverse conditions or damaged structures,and root regeneration allows the plant body to better adapt to its environment by supplementing the roots’...Plant regeneration is a self-repair of the plant body in response to adverse conditions or damaged structures,and root regeneration allows the plant body to better adapt to its environment by supplementing the roots’structure.Previous research has shown that adventitious roots can be made to occur from scratch in two ways.Studies that simulate adventitious root regeneration through natural conditions allow the regeneration process to be broadly divided into three stages:the perception of early signals,the massive accumulation of auxin,and the transformation of cell fate.The strength of regeneration,in turn,is influenced by wounding,stress,hormones,etc.This study mainly reviews the molecular mechanisms of de novo adventitious roots and discusses how the environment,hormones,and its own development in Arabidopsis thaliana.展开更多
Plants are a rich source of valuable secondary metabolites and in the recent years plant cell, tissue and organ cultures have been developed as an important alternative sources for the production of these compounds. A...Plants are a rich source of valuable secondary metabolites and in the recent years plant cell, tissue and organ cultures have been developed as an important alternative sources for the production of these compounds. Adventitious roots have been successfully induced in many plant species and cultured for the production of high value secondary metabolites of pharmaceutical, nutraceutical and industrial importance. Adoption of elicitation methods have shown improved synthesis of secondary metabolites in adventitious root cultures. Development of large-scale culture methods using bioreactors has opened up feasibilities of production of secondary metabolites at the industrial levels. In the present review we summarize the progress made in recent past in the area of adventitious root cultures for the production of secondary metabolites.展开更多
duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed a...duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed adventitious roots and a deeply distributed main root system. To detect water movement between the main root system and adventitious roots, we adopted heat pulse sensors using the Heat Ratio Method, a high precision method for measuring low sap flow rates. Two sensors were implanted in each individual in the stem between the main root system and adventitious roots, and another two in lateral stems distal to all the roots. Positive sap flows during nighttime, even under saturated air moisture conditions, were detected only between the main root system and adventitious roots under drought conditions, and the rate of flow increased as drought progressed and decreased or disappeared after rain events. The results demonstrated the existence of water movement from the main root system to adventitious roots, and combined with the high contribution of nighttime sap flow to transpiration （11%-16%） the results indicate that it also involves the process of hydraulic lift, a water movement from moist subsoil to dry surface soils. Integrated water use strategy between the main root system and adventitious roots via the process of hydraulic lift of soil water maximizes water acquisition efficiency from both subsoil water and water from rain pulses on the soil surface; this increases survivability in the water-limited environment of semiarid areas.展开更多
Microshoots of Castanea mollissima cv.＇yanshanhong＇ in vitro acquired an enhanced rooting capability with increasing numbers of subculture.In this study,we investigated the effect of successive subculture on adventi...Microshoots of Castanea mollissima cv.＇yanshanhong＇ in vitro acquired an enhanced rooting capability with increasing numbers of subculture.In this study,we investigated the effect of successive subculture on adventitious root formation in vitro by the determination of the endogenous hormone level and the enzyme activity.The levels of indoleacetic acid（IAA）,abscisic acid（ABA）,cytokinins（CTK） and gibberellic acid（GA3） were determined by high performance liquid chromatography（HPLC）,and the activities of indoleacetic acid oxidase（IAAO）,peroxidase oxidase（POD）,and polyphenol oxidase（PPO） were measured by ultraviolet-spectrophotometer assay after the induction of rooting at 2nd,4th,6th and 8th subculture.The relationships between physiological characteristics and subculture numbers or rooting rate were as follows：The levels of endogenous IAA in microshoots gradually increased,and endogenous levels of ABA,CTK and GA3 in microshoots decreased slightly after serial subcultures.The level of IAA was highly correlated with subculture numbers and rooting rates.The ratios of IAA/ABA and IAA/CTK both acutely raised with increasing rooting rate during successive subcultures and had high correlations with rooting rate.The activity of IAAO and POD are significantly negatively related with subculture numbers,and the activity of PPO increased after subcultures.展开更多
The effects of neodymium nitrate （Nd^3＋） on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3＋ （5 μmol/L） to culture medium significantly increased rooting fre...The effects of neodymium nitrate （Nd^3＋） on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3＋ （5 μmol/L） to culture medium significantly increased rooting frequency. Histological investigation showed that Nd^3＋ did not change the process of root initiation. Nd^3＋ did not influence total endogenous cytokinin levels, but significantly increased the level of endogenous indole-3-acetic acid （IAA） in the base of shoot cuttings. Compared to the control, the ratio of IAA/cytokinins was very high in the Nd^3＋ treatment. These results suggested that the enhanced rooting frequency may be related to the increase in endogenous IAA level in Nd^3＋ treatment. Analysis of enzyme activities showed that the enhanced accumulation of the endogenous IAA by Nd^3＋ should not be attributed to inhibition of IAA decomposition by IAA oxidase or promotion of cytokinin decomposition by cytokinin oxidase. Besides, Nd^3＋ increased the ratio of reduced glutathione （GSH） and oxidized glutathione （GSSG） in the process of adventitious rooting while the ratio of ascorbate （ASC） to dehydroascorbate （DHA） was not affected.展开更多
Optimization of in vitro adventitious root induction contributes to the development of a large-scale production system of hybrid clone seedlings of larch(Larix spp.).We used orthogonal testing to investigate the facto...Optimization of in vitro adventitious root induction contributes to the development of a large-scale production system of hybrid clone seedlings of larch(Larix spp.).We used orthogonal testing to investigate the factors that affect the rooting of hybrid larch shoots-activated carbon,vitamin B1,sucrose,glycine,glutamic acid(Glu),cysteine,pH,and induction time in the dark and indole-3-butyric acid(IBA).Variance analysis showed that the effects of sucrose concentration on rooting rate,survival rate,and average root number,pH on the average number of roots;and Glu on survival rate were all significant(p<0.05)when compared to the mock treatments.Among all of the 45 treatments,the highest rooting rate was 90%,the highest survival rate was 100%,and the highest average root number was 11.8.The theoretically optimal procedure of in vitro root induction of hybrid larch shoots is shoot induction on L9 modified medium(pH 6.7)containing 2 mg.L^(-1)naphthalene acetic acid,0.25 mg.L^(-1)IBA,1/3 macroelements,7.5 g.L^(-1)sucrose,and 5 mg.L^(-1)Glu for 8 days,and then root induction on L9 modified medium without auxin.展开更多
The fibrous root system in cereals comprises primarily adventitious roots （ARs）, which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development...The fibrous root system in cereals comprises primarily adventitious roots （ARs）, which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development is still limited. We report here the isolation of four rice （Oryza sativa L.） mutants, from different genetic backgrounds, all of which were defective in AR formation. These mutants exhibited reduced numbers of lateral roots （LRs） and partial loss of gravitropism. The mutants also displayed enhanced sensitivity to N-l-naphthylphthalamic acid, an inhibitor of polar auxin transport （PAT）, indicating that the mutations affected auxin transport. Positional cloning using one of the four mutants revealed that it was caused by loss-of-function of a guanine nucleotide exchange factor for ADP- ribosylation factor （OsGNOM1）. RT-PCR and analysis of promoter：：GUS transgenic plants showed that OsGNOM1 is expressed in AR primordia, vascular tissues, LRs, root tips, leaves, anthers and lemma veins, with a distribution pattern similar to that of auxin. In addition, the expressions of OsPIN2, OsPIN5b and OsPIN9 were altered in the mutants. Taken together, these findings indicate that OsGNOM1 affects the formation of ARs through regulating PAT.展开更多
Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mech- nisms of the adventitious rooting and the regulation of rooting processes are the principles ...Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mech- nisms of the adventitious rooting and the regulation of rooting processes are the principles and techniques of plant propagation and improvement. Microstructures and fluctuations of phytohormones in the adventitious rooting were studied with the etiolated soft- wood shoots of Paeonia suffkuticosa ＇Yinfen Jinlin＇. There are no pre-primordia in the shoots of the cultivar. Adventitious roots are produced in five stages： shoot selection, primordium initiation, primordium growth, conducting tissue differentiation and root protru- sion. Primordia initiated in the cortex. The contents of the endogenous hormones, IAA, ABA and GA, were 5.842, 0.873 and 1.043 nmol·g^-1 FW on the bases of shoots, respectively. CTKs which included isopentenyl adenine （iPA）, zeatin riboside （ZR） and dihy- drozeatin riboside （DHZR） were 0.949, 0.695 and 2.034 nmol·g^-1 FW, respectively. DHZR is active among CTKs. The ratio of IAA to GA, CTK and ABA clearly increased at the stage of primordium initiation, while they showed low levels at the stages of primor- dium growth. The ratios were restored at the shoot levels at the stage of root protrusion. IBA provoked primordia initiation in the cortex, the vascular cambium, the pith and even in the callus induced on the base of shoots. ]AA levels in the treated shoots increased gradually to its highest level （three times of control） at the stage of conducting tissue differentiation. The ratios of IAA to GA, CTK and ABA clearly decreased at the stage of primordium initiation. The ratio of IAA to ABA is regulated at 10：1.展开更多
This paper reviews the internal influence factors of adventitious root, in- ducing oxidase activity, endogenous hormones, rooting inhibiting substances, and fu- ture research ideas are also proposed.
The plant-specific WUSCHEL-related homeobox(WOX)genes are crucial for plant growth and development.Here,we systematically identified the MdWOX gene family in apple at the genome-wide level,and analyzed the phylogeneti...The plant-specific WUSCHEL-related homeobox(WOX)genes are crucial for plant growth and development.Here,we systematically identified the MdWOX gene family in apple at the genome-wide level,and analyzed the phylogenetic relationships,conserved motifs,gene structure,and syntenic relationships of the MdWOX genes.A total of 18 MdWOX genes were identified and phylogenetic analysis placed them into three clades.The phylogenetic relationships among the WOXs were further supported by the analyses of gene structure and conserved motifs.Chromosomal distribution and synteny analysis revealed that whole-genome and segmental duplications have played key roles in MdWOX gene family expansion.Moreover,the MdWOX genes exhibit tissue-specific expression patterns and MdWOX4a,MdWOX4b,MdWOX5b,MdWOX11/12a,and MdWOX11/12b may play essential roles in adventitious root development.The adventitious rooting ability was enhanced in MdWOX4b transgenic tobacco lines.The results of this study provide useful information for future functional studies on MdWOXs in the development of apple rootstocks.展开更多
The effect of stock-plant etiolation on adventitious rooting of single-node leafy cuttings (SNCs) made from coppice shoots from different age groups of donor plants were investigated for teak (Tectona grandis Linn. f....The effect of stock-plant etiolation on adventitious rooting of single-node leafy cuttings (SNCs) made from coppice shoots from different age groups of donor plants were investigated for teak (Tectona grandis Linn. f.). When donor plants age were 1-, 2-, 3-, 4-, and 5-year-old, they were coppiced and maintained in the dark for etiolation, while a parallel set was kept in normal light in an open environment. After 20 days, coppice shoots were made into SNCs which were cultured under intermittent mist for rooting. Stock-plant etiolation significantly increased percent rooting, shoot and root length, and number of roots per SNC, but callusing at the base of SNCs decreased. Etiolated SNCs have shown 71.7% rooting, whereas for controls (non-etiolated), the response was 41.7%. The effect of aging on callusing, rooting and sprouting of etiolated and non-etiolated coppice shoots cuttings varied widely. Aging of donor plants decreased rooting and sprouting capability in SNCs and increased callusing at the base of etiolated cuttings. The results showed that stock-plant etiolation in 1-, 2-, 3-, 4-, and 5-year-old donor plants hastened rooting potential by rejuvenation of coppice shoots.展开更多
[ Objective] The aim was to establish efficient regeneration system of tomato so as to study the genetic transformation of chloroplast in tomato. [ Meth- od] The tomato seeds were sterilized and cultured into plantlet...[ Objective] The aim was to establish efficient regeneration system of tomato so as to study the genetic transformation of chloroplast in tomato. [ Meth- od] The tomato seeds were sterilized and cultured into plantlets. Then, the leaves were cut from plantlets and placed in the MS with 3.0 mg/L 6-BA ＋ 0.3 mg/L IAA to induce callus. Finally, the effect of different hormones and concentrations on induction of adventitious buds from tomato callus and rooting was compared. [Result] The best medium for the induction of differentiation of adventitious buds from callus was： MS ＋ 2.0 mg/L 6-BA ＋ 0.3 mg/L sugar. The best medium for rooting was： 1/2MS ＋ 1.0 mg/L IAA. [ Conclusion] Appropriate sdection of hormone concentrations is the key to establish efficient regeneration system for tomato.展开更多
In several countries in monsoon Asia, soybean crops are cultivated in upland fields converted from paddies. In such fields, excess soil water often induces extensive damage followed by lower nutrient uptake by this cr...In several countries in monsoon Asia, soybean crops are cultivated in upland fields converted from paddies. In such fields, excess soil water often induces extensive damage followed by lower nutrient uptake by this crop. In this study, the effects of flooding during the early growth stage of pot-grown soybeans on arbuscular mycorrhizal (AM) colonization and root nodule formation were investigated. Twenty days after sowing cv. Fukuyutaka, half of the pots were flooded (flooding) and the other half were left unflooded (irrigation). The plants were sampled after 39 days of flooding. Typical morphological alterations to flooding were found, including an enlarged hypocotyl diameter and partial cracking of the surface tissues, and adventitious roots developed on the soil surface. The primary and lateral roots were shorter and the adventitious roots were longer in flooding than in irrigation. In flooding, the ratio of the aerenchyma area to the stele area was 82.5% in adventitious roots. The AM colonization ratio in flooding was significantly lower than in irrigation. The ratio in flooding was markedly low in the primary and lateral roots, but it was not necessarily low in the adventitious roots. Root nodules were formed on the adventitious roots but not on the primary and lateral roots, especially in flooding. These results showing different rates of AM colonization and root nodule formation between the two different types of roots improve the understanding of responses of soybeans grown in paddy-rotated upland fields.展开更多
An efficient in vitro method for rapid vegetative propagation of Bienertia sinuspersici, one of four terrestrial species of family Chenopodiaceae capable of performing C4 photosynthesis within a single cell, was devel...An efficient in vitro method for rapid vegetative propagation of Bienertia sinuspersici, one of four terrestrial species of family Chenopodiaceae capable of performing C4 photosynthesis within a single cell, was developed. Cuttings of B. sinuspersici were used to examine the effects of Murashige and Skoog (MS) media strength and auxins on adventitious root formation. Half-strength MS medium was determined to be ideal for adventitious root formation in Bienertia cuttings. Although cuttings cultured in medium containing 5.0 mg/L α-naphthalene acetic acid (NAA) promoted the highest number of adventitious roots, cuttings cultured in medium supplemented with 1.0 mg/L indole-3-butyric acid (IBA) produced the longest adventitious roots and had the highest survival rate upon transplanting to soil. Histological analysis revealed variations in the root anatomy generated by the various auxins which may affect adventitious root formation and subsequent establishment of cuttings in soil. Overall, the established procedure provides a simple and cost-effective means for the rapid propagation of the single-cell C4 species B. sinuspersici.展开更多
In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radia...In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radiata. However, the capability of produce adventitious roots in gymnosperms decreases with aging. While it is true that some efforts have been made to identify markers or/and regulators of the aging process and adventitious rooting, molecular mechanisms that regulate both processes are scarcely known, especially at protein level. This research evaluated qualitative and quantitative changes in protein accumulation during the adventitious rooting process of P. radiata stem cuttings, with different rooting capabilities. Beside, an analysis of morpho-anatomical changes was performed in stem cuttings with high and low rooting capabilities, during the adventitious rooting process. It was observed that juvenile 1-year-old stem cuttings rooted in a 100%, while aged stem cuttings (3-year-old) presented only a 20% of rooting. According to the results of differential protein accumulation, univariate and multivariate analysis indicated that in total, 114 and 89 proteins were differentially accumulated in juvenile and aged cuttings, respectively. Also, identification of such proteins showed the presence of proteins related to cell wall organization and the presence of a protein related with proper distribution of auxin PIN transporter, both key in the new meristem formation process during adventitious rooting.展开更多
Polar auxin transport (PAT) is critical in plant growth and development, especially polar differentiation and pattern formation. Lots of studies have been performed in dicots while relative less in monocots. Using two...Polar auxin transport (PAT) is critical in plant growth and development, especially polar differentiation and pattern formation. Lots of studies have been performed in dicots while relative less in monocots. Using two kinds of PAT inhibitors, 2, 3, 5-triiodobenzoic acid (TIBA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA), it was shown that PAT is important for rice (Oryza sativa L. cv. Zhonghua 11) root development, including elongation of the primary roots, initiation and elongation of lateral roots, and formation of adventitious roots. Inhibition of PAT resulted in the shortened primary roots, less and shortened lateral and adventitious roots. Exogenously supplemented NAA can partially rescue the formation of adventitious roots but not lateral roots, while low concentration of NAA (0.1 mumol/L) could not rescue either of them, suggesting the possible different mechanisms of lateral and adventitious root initiations. Treatment of 30 mumol/L TIBA did not completely inhibit the initiation of lateral roots, and survival capacities of which were demonstrated through cross section experiments revealing the presence of primordial of lateral roots at different stages. Further studies through localized application of PAT inhibitors indicated that auxin flow, transported from coleoptiles to the base, is not only responsible for the auxin contents in stem nodes but also critical for initiation and elongation of adventitious roots.展开更多
基金financially supported by the National Natural Science Foundation of China(32372675,32372657,32102359)the National Key Research and Development Project,China(2023YFD2301002)+5 种基金the Young Talent Fund of Association for Science and Technology in Shaanxi,China(20240218)the Science and Technology Major Project of Xinjiang Production and Construction Corps,China(2023AB077)the Chinese Universities Scientific Fund(2452023005)the China Apple Research System(CARS-27)the Cyrus Tang Foundationthe Fundamental Research Funds for the Central Universities,China。
文摘Potassium nitrate(KNO_(3))promotes adventitious root(AR)formation in apple stem cuttings.However,evidence for the possible involvement of cytokinin(CK)in KNO_(3)-mediated AR formation in apples is still lacking.In this study,we cultured GL-3 apple microshoots in different treatment combinations.While the T1(KNO_(3)9.4 mmol L^(-1)+6-benzyl adenine(6-BA)2.22μmol L^(-1))and T3(6-BA 2.22μmol L^(-1))treatments completely inhibited AR formation,the control,T2(KNO_(3)9.4 mmol L^(-1)),and T4(KNO_(3)9.4 mmol L^(-1)+lovastatin(Lov)1.24μmol L^(-1))treatments developed ARs.However,T4-treated microshoots developed fewer and shorter ARs,indicating that optimum CK synthesis is needed for normal AR growth.This also suggests that these fewer and shorter ARs developed because of the presence of KNO_(3) in the same medium.The anatomy of the stem basal part indicated that the inhibition of CK biosynthesis delayed AR primordia formation.The endogenous levels of indole-3-acetic acid(IAA)and zeatin riboside(ZR)were higher in T2-treated microshoots,while the abscisic acid(ABA),gibberellic acid 3(GA_(3)),and brassinosteroid(BR)levels were higher in T4-treated microshoots.The expression levels of MdNRT1.1and MdNRT2.1 were higher in T2-treated microshoots at 3 and 8 days,while MdRR2 and MdCKX5 were higher at 8 and 16 days,respectively.Furthermore,higher IAA levels increased MdWOX11 expression,which in turn increased MdLBD16 and MdLBD29 expression in response to T2.The combined expression of these genes stimulated adventitious rooting by upregulating cell cycle-related genes(MdCYCD1;1 and MdCYCD3;1)in response to T2 treatment.This study shows that specific genes and hormonal pathways contribute to KNO_(3)-CK-mediated adventitious rooting in apples.
基金supported by Jiangsu Provincial Basic Research Program(Natural Science Foundation,Grant No.BK20241175)The project of Agriculture Ministry Key Laboratory of Agricultural Engineering in the Middle and Lower Reaches of Yangtze River[Grant No.(23)3104]Jiangsu Agricultural Science and Technology Innovation Fund[Grant No.CX(21)2022]。
文摘Root regeneration is an important factor influencing the healing rate of graft union and the survival of double-root-cutting grafting.To date,little information is available on how to enhance root regeneration of rootstock in grafted watermelon(Citrullus lanatus)seedlings.In this study,the effects of different light treatments on root regeneration were determined.This revealed that addition of far-red light(Fr)could significantly expedite root formation in the rootstock.Moreover,the results of transcriptome analysis revealed that plant hormone pathway and auxinrelated genes were greatly induced by Fr,especially for auxin-response proteins(including CmIAA11,CmIAA17,and CmAUX28),Small auxinup RNA genes(including CmSAUR20 and CmSAUR50)and the auxin efflux transporter(CmPIN3).In addition,the expression of Phytochrome Interacting Factor(PIFs),such as CmPIF1,CmPIF3 and CmPIF7,was remarkably increased by Fr.These genes may act together to activate auxinrelated pathways under Fr treatment.Based on the results of HPLC-MS/MS analysis,the concentrations of different auxin-types in adventitious root were significantly influenced by Fr.Furthermore,the better growth of rootstock root displayed superior vasculature transport activity of the graft union with Fr treatment,which was determined by the acid magenta dyeing experiment.Therefore,all the results suggested that Fr could induce AR formation in rootstocks,which may be associated with the auxin accumulation by regulating the transcriptional level of auxinrelated and PIF genes.The findings of this study demonstrated a practicable way to shorten the healing period of graftings and improve the quality of grafted watermelon seedlings,which will provide a theoretical basis for the speeding development of industrialized seedlings production.
基金supported by the National Natural Science Foundation of China(Grant No.32101479)。
文摘Inducing adventitious root(AR)formation in mature walnut species(Juglans L.)is challenging.However,the AR formation of mature trees can be improved by rejuvenation.In rejuvenated cuttings,exogenous indole-3-butyric acid(IBA)is essential for AR formation,and the underlying mechanism is still not well understood.Therefore,we utilized transcriptome sequencing to investigate the mechanism of IBA-induced AR formation.Our results revealed that,in comparison to the control group,IBA treatment(9 mmol·L^(-1))significantly increased the endogenous indole-3-acetic acid(IAA)content,leading to an enhanced rooting rate.We performed RNA sequencing to identify differentially expressed genes(DEGs)between the IBA-treated and control(CK)groups at 1,2,3,and 5 days after cutting(DAC).The results showed that,compared to the control cuttings,there were 1539,889,785,and 984 up-regulated genes and 2791,2936,3017,and 1752 down-regulated genes,at 1,2,3,and 5 DAC,respectively.Analysis of RNA-seq data revealed that G-type ATP-binding cassette 36/37(ABCG36/37)and ATP-binding cassette subfamily D 1(ABCD1),associated with IBA transport,were down-regulated in the rejuvenation cuttings.In contrast,PIN-FORMED(PIN)and PINOID(PID),associated with auxin efflux,were up-regulated.We identified 49 auxin/indole-3-acetic acid(AUX/IAA)-encoding genes,including IAA1,IAA3,IAA5,IAA6,IAA8,IAA11,IAA12,IAA19,and IAA20,which were up-regulated at 1-5 DAC in the rejuvenated cuttings.This study highlights that the overexpression of JrWOX5/11 in poplar significantly enhance AR growth,as evidenced by increased root length,surface area,volume,and quantity.Moreover,the co-expression network analysis involving JrWOX11 and JrWOX5 in walnut cuttings elucidates complex genetic interactions,underscoring their pivotal role in the formation of AR.Our data supported the following molecular mechanism of IBA-induced adventitious root formation.Firstly,IBA is converted to free IAA in peroxisomes.Then,the highly concentrated IAA in the procambium and parenchyma cells induces WUSCHEL-related homeobox 11(WOX11)expression at two days.Finally,WOX11 acts redundantly to up-regulate WOX5,initiating the development of root primordia cells.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFD1000101,2019YFD1000803)Shaanxi Apple Industry Science and Technology Project(Grant No.2020zdzx03-01-04)+1 种基金Tang Scholar by Cyrus Tang Foundation(Grant No.C200022002)The China Apple Research System(Grant No.CARS-27).
文摘Adventitious root formation is a bottleneck during vegetative proliferation.Potassium(K^(+))is an essential macronutrient for plants.K^(+)accumulation from the soil and its distribution to the different plant organs is mediated by K^(+)transporters named K^(+)transporter(KT),K^(+)uptake(KUP),or high-affinity K^(+)(HAK).This study aimed to identify members of the HAK gene family in apples and to characterize the effects of K^(+)supply on adventitious root formation and on the expression of HAK genes and the genes that putatively control auxin transport,signaling,and cell fate during adventitious root formation.In this study,34 HAK genes(MdHAKs)were identified in the apple(Malus×domestica‘Golden Delicious’)genome.A phylogenetic analysis divided MdHAKs into four clusters(Ⅰ,Ⅱ,Ⅲ,andⅣ),comprising 16,1,4,and 13 genes,respectively.The syntenic relationships revealed that 62.5%of the total MdHAK genes arise from genomic duplication events.Chromosome location,domain structure,motif analysis,and physico-chemical characteristics were subsequently investigated.Furthermore,the application of K^(+)indicated the emergence of adventitious roots at 8 d and produced more adventitious roots at 16 d than the K^(+)-free control(CK)treatment.In addition,various MdHAKs showed root-specific expression in B9 apple rootstock stem cuttings and enhanced expression during the initiation and emergence stages of adventitious root formation in response to K^(+)treatment.Additionally,K^(+)treatment enhanced the expression levels of MdPIN1,MdPIN2,and MdAUX1.Further data indicated that a higher expression of MdWOX11,MdLBD16,and MdLBD29 and of cell cycle-related genes contributed to the auxin-stimulated adventitious root formation in response to K^(+).
文摘Plant regeneration is a self-repair of the plant body in response to adverse conditions or damaged structures,and root regeneration allows the plant body to better adapt to its environment by supplementing the roots’structure.Previous research has shown that adventitious roots can be made to occur from scratch in two ways.Studies that simulate adventitious root regeneration through natural conditions allow the regeneration process to be broadly divided into three stages:the perception of early signals,the massive accumulation of auxin,and the transformation of cell fate.The strength of regeneration,in turn,is influenced by wounding,stress,hormones,etc.This study mainly reviews the molecular mechanisms of de novo adventitious roots and discusses how the environment,hormones,and its own development in Arabidopsis thaliana.
文摘Plants are a rich source of valuable secondary metabolites and in the recent years plant cell, tissue and organ cultures have been developed as an important alternative sources for the production of these compounds. Adventitious roots have been successfully induced in many plant species and cultured for the production of high value secondary metabolites of pharmaceutical, nutraceutical and industrial importance. Adoption of elicitation methods have shown improved synthesis of secondary metabolites in adventitious root cultures. Development of large-scale culture methods using bioreactors has opened up feasibilities of production of secondary metabolites at the industrial levels. In the present review we summarize the progress made in recent past in the area of adventitious root cultures for the production of secondary metabolites.
文摘duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed adventitious roots and a deeply distributed main root system. To detect water movement between the main root system and adventitious roots, we adopted heat pulse sensors using the Heat Ratio Method, a high precision method for measuring low sap flow rates. Two sensors were implanted in each individual in the stem between the main root system and adventitious roots, and another two in lateral stems distal to all the roots. Positive sap flows during nighttime, even under saturated air moisture conditions, were detected only between the main root system and adventitious roots under drought conditions, and the rate of flow increased as drought progressed and decreased or disappeared after rain events. The results demonstrated the existence of water movement from the main root system to adventitious roots, and combined with the high contribution of nighttime sap flow to transpiration （11%-16%） the results indicate that it also involves the process of hydraulic lift, a water movement from moist subsoil to dry surface soils. Integrated water use strategy between the main root system and adventitious roots via the process of hydraulic lift of soil water maximizes water acquisition efficiency from both subsoil water and water from rain pulses on the soil surface; this increases survivability in the water-limited environment of semiarid areas.
基金supported by Special Scientific Research Fund for Doctor Subjects of Universities(NO20060022010)China National key Tech R&D Program (No2006BAD18B0202)
文摘Microshoots of Castanea mollissima cv.＇yanshanhong＇ in vitro acquired an enhanced rooting capability with increasing numbers of subculture.In this study,we investigated the effect of successive subculture on adventitious root formation in vitro by the determination of the endogenous hormone level and the enzyme activity.The levels of indoleacetic acid（IAA）,abscisic acid（ABA）,cytokinins（CTK） and gibberellic acid（GA3） were determined by high performance liquid chromatography（HPLC）,and the activities of indoleacetic acid oxidase（IAAO）,peroxidase oxidase（POD）,and polyphenol oxidase（PPO） were measured by ultraviolet-spectrophotometer assay after the induction of rooting at 2nd,4th,6th and 8th subculture.The relationships between physiological characteristics and subculture numbers or rooting rate were as follows：The levels of endogenous IAA in microshoots gradually increased,and endogenous levels of ABA,CTK and GA3 in microshoots decreased slightly after serial subcultures.The level of IAA was highly correlated with subculture numbers and rooting rates.The ratios of IAA/ABA and IAA/CTK both acutely raised with increasing rooting rate during successive subcultures and had high correlations with rooting rate.The activity of IAAO and POD are significantly negatively related with subculture numbers,and the activity of PPO increased after subcultures.
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (20060359006)
文摘The effects of neodymium nitrate （Nd^3＋） on the adventitious rooting of Dendrobium densiflorum shoot cuttings were studied. The addition of Nd^3＋ （5 μmol/L） to culture medium significantly increased rooting frequency. Histological investigation showed that Nd^3＋ did not change the process of root initiation. Nd^3＋ did not influence total endogenous cytokinin levels, but significantly increased the level of endogenous indole-3-acetic acid （IAA） in the base of shoot cuttings. Compared to the control, the ratio of IAA/cytokinins was very high in the Nd^3＋ treatment. These results suggested that the enhanced rooting frequency may be related to the increase in endogenous IAA level in Nd^3＋ treatment. Analysis of enzyme activities showed that the enhanced accumulation of the endogenous IAA by Nd^3＋ should not be attributed to inhibition of IAA decomposition by IAA oxidase or promotion of cytokinin decomposition by cytokinin oxidase. Besides, Nd^3＋ increased the ratio of reduced glutathione （GSH） and oxidized glutathione （GSSG） in the process of adventitious rooting while the ratio of ascorbate （ASC） to dehydroascorbate （DHA） was not affected.
基金This research was funded by The National Key Research and Development Program of China(Project No.2017YFD0600401).
文摘Optimization of in vitro adventitious root induction contributes to the development of a large-scale production system of hybrid clone seedlings of larch(Larix spp.).We used orthogonal testing to investigate the factors that affect the rooting of hybrid larch shoots-activated carbon,vitamin B1,sucrose,glycine,glutamic acid(Glu),cysteine,pH,and induction time in the dark and indole-3-butyric acid(IBA).Variance analysis showed that the effects of sucrose concentration on rooting rate,survival rate,and average root number,pH on the average number of roots;and Glu on survival rate were all significant(p<0.05)when compared to the mock treatments.Among all of the 45 treatments,the highest rooting rate was 90%,the highest survival rate was 100%,and the highest average root number was 11.8.The theoretically optimal procedure of in vitro root induction of hybrid larch shoots is shoot induction on L9 modified medium(pH 6.7)containing 2 mg.L^(-1)naphthalene acetic acid,0.25 mg.L^(-1)IBA,1/3 macroelements,7.5 g.L^(-1)sucrose,and 5 mg.L^(-1)Glu for 8 days,and then root induction on L9 modified medium without auxin.
基金Acknowledgments This work was supported by the Key Basic Research Special Foundation of China （2005CB20900）, the National High Technology Research and Development Program （2007AA021403, 2006AA10Z 175）, the National Natural Science Foundation of China （30471118 and 30770191） and the Specialized Research Fund for the Doctoral Program of Higher Education （20070335081）.
文摘The fibrous root system in cereals comprises primarily adventitious roots （ARs）, which play important roles in nutrient and water uptake. Current knowledge regarding the molecular mechanism underlying AR development is still limited. We report here the isolation of four rice （Oryza sativa L.） mutants, from different genetic backgrounds, all of which were defective in AR formation. These mutants exhibited reduced numbers of lateral roots （LRs） and partial loss of gravitropism. The mutants also displayed enhanced sensitivity to N-l-naphthylphthalamic acid, an inhibitor of polar auxin transport （PAT）, indicating that the mutations affected auxin transport. Positional cloning using one of the four mutants revealed that it was caused by loss-of-function of a guanine nucleotide exchange factor for ADP- ribosylation factor （OsGNOM1）. RT-PCR and analysis of promoter：：GUS transgenic plants showed that OsGNOM1 is expressed in AR primordia, vascular tissues, LRs, root tips, leaves, anthers and lemma veins, with a distribution pattern similar to that of auxin. In addition, the expressions of OsPIN2, OsPIN5b and OsPIN9 were altered in the mutants. Taken together, these findings indicate that OsGNOM1 affects the formation of ARs through regulating PAT.
文摘Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mech- nisms of the adventitious rooting and the regulation of rooting processes are the principles and techniques of plant propagation and improvement. Microstructures and fluctuations of phytohormones in the adventitious rooting were studied with the etiolated soft- wood shoots of Paeonia suffkuticosa ＇Yinfen Jinlin＇. There are no pre-primordia in the shoots of the cultivar. Adventitious roots are produced in five stages： shoot selection, primordium initiation, primordium growth, conducting tissue differentiation and root protru- sion. Primordia initiated in the cortex. The contents of the endogenous hormones, IAA, ABA and GA, were 5.842, 0.873 and 1.043 nmol·g^-1 FW on the bases of shoots, respectively. CTKs which included isopentenyl adenine （iPA）, zeatin riboside （ZR） and dihy- drozeatin riboside （DHZR） were 0.949, 0.695 and 2.034 nmol·g^-1 FW, respectively. DHZR is active among CTKs. The ratio of IAA to GA, CTK and ABA clearly increased at the stage of primordium initiation, while they showed low levels at the stages of primor- dium growth. The ratios were restored at the shoot levels at the stage of root protrusion. IBA provoked primordia initiation in the cortex, the vascular cambium, the pith and even in the callus induced on the base of shoots. ]AA levels in the treated shoots increased gradually to its highest level （three times of control） at the stage of conducting tissue differentiation. The ratios of IAA to GA, CTK and ABA clearly decreased at the stage of primordium initiation. The ratio of IAA to ABA is regulated at 10：1.
文摘This paper reviews the internal influence factors of adventitious root, in- ducing oxidase activity, endogenous hormones, rooting inhibiting substances, and fu- ture research ideas are also proposed.
基金funded by the National Natural Science Foundation of China(31801824)the Breeding Plan of Shandong Provincial Qingchuang Research Team,China(2019)the Scientific Research Funds for Highlevel Personnel of Qingdao Agricultural University,China(663/1118036 and 663/1119046)。
文摘The plant-specific WUSCHEL-related homeobox(WOX)genes are crucial for plant growth and development.Here,we systematically identified the MdWOX gene family in apple at the genome-wide level,and analyzed the phylogenetic relationships,conserved motifs,gene structure,and syntenic relationships of the MdWOX genes.A total of 18 MdWOX genes were identified and phylogenetic analysis placed them into three clades.The phylogenetic relationships among the WOXs were further supported by the analyses of gene structure and conserved motifs.Chromosomal distribution and synteny analysis revealed that whole-genome and segmental duplications have played key roles in MdWOX gene family expansion.Moreover,the MdWOX genes exhibit tissue-specific expression patterns and MdWOX4a,MdWOX4b,MdWOX5b,MdWOX11/12a,and MdWOX11/12b may play essential roles in adventitious root development.The adventitious rooting ability was enhanced in MdWOX4b transgenic tobacco lines.The results of this study provide useful information for future functional studies on MdWOXs in the development of apple rootstocks.
文摘The effect of stock-plant etiolation on adventitious rooting of single-node leafy cuttings (SNCs) made from coppice shoots from different age groups of donor plants were investigated for teak (Tectona grandis Linn. f.). When donor plants age were 1-, 2-, 3-, 4-, and 5-year-old, they were coppiced and maintained in the dark for etiolation, while a parallel set was kept in normal light in an open environment. After 20 days, coppice shoots were made into SNCs which were cultured under intermittent mist for rooting. Stock-plant etiolation significantly increased percent rooting, shoot and root length, and number of roots per SNC, but callusing at the base of SNCs decreased. Etiolated SNCs have shown 71.7% rooting, whereas for controls (non-etiolated), the response was 41.7%. The effect of aging on callusing, rooting and sprouting of etiolated and non-etiolated coppice shoots cuttings varied widely. Aging of donor plants decreased rooting and sprouting capability in SNCs and increased callusing at the base of etiolated cuttings. The results showed that stock-plant etiolation in 1-, 2-, 3-, 4-, and 5-year-old donor plants hastened rooting potential by rejuvenation of coppice shoots.
文摘[ Objective] The aim was to establish efficient regeneration system of tomato so as to study the genetic transformation of chloroplast in tomato. [ Meth- od] The tomato seeds were sterilized and cultured into plantlets. Then, the leaves were cut from plantlets and placed in the MS with 3.0 mg/L 6-BA ＋ 0.3 mg/L IAA to induce callus. Finally, the effect of different hormones and concentrations on induction of adventitious buds from tomato callus and rooting was compared. [Result] The best medium for the induction of differentiation of adventitious buds from callus was： MS ＋ 2.0 mg/L 6-BA ＋ 0.3 mg/L sugar. The best medium for rooting was： 1/2MS ＋ 1.0 mg/L IAA. [ Conclusion] Appropriate sdection of hormone concentrations is the key to establish efficient regeneration system for tomato.
文摘In several countries in monsoon Asia, soybean crops are cultivated in upland fields converted from paddies. In such fields, excess soil water often induces extensive damage followed by lower nutrient uptake by this crop. In this study, the effects of flooding during the early growth stage of pot-grown soybeans on arbuscular mycorrhizal (AM) colonization and root nodule formation were investigated. Twenty days after sowing cv. Fukuyutaka, half of the pots were flooded (flooding) and the other half were left unflooded (irrigation). The plants were sampled after 39 days of flooding. Typical morphological alterations to flooding were found, including an enlarged hypocotyl diameter and partial cracking of the surface tissues, and adventitious roots developed on the soil surface. The primary and lateral roots were shorter and the adventitious roots were longer in flooding than in irrigation. In flooding, the ratio of the aerenchyma area to the stele area was 82.5% in adventitious roots. The AM colonization ratio in flooding was significantly lower than in irrigation. The ratio in flooding was markedly low in the primary and lateral roots, but it was not necessarily low in the adventitious roots. Root nodules were formed on the adventitious roots but not on the primary and lateral roots, especially in flooding. These results showing different rates of AM colonization and root nodule formation between the two different types of roots improve the understanding of responses of soybeans grown in paddy-rotated upland fields.
文摘An efficient in vitro method for rapid vegetative propagation of Bienertia sinuspersici, one of four terrestrial species of family Chenopodiaceae capable of performing C4 photosynthesis within a single cell, was developed. Cuttings of B. sinuspersici were used to examine the effects of Murashige and Skoog (MS) media strength and auxins on adventitious root formation. Half-strength MS medium was determined to be ideal for adventitious root formation in Bienertia cuttings. Although cuttings cultured in medium containing 5.0 mg/L α-naphthalene acetic acid (NAA) promoted the highest number of adventitious roots, cuttings cultured in medium supplemented with 1.0 mg/L indole-3-butyric acid (IBA) produced the longest adventitious roots and had the highest survival rate upon transplanting to soil. Histological analysis revealed variations in the root anatomy generated by the various auxins which may affect adventitious root formation and subsequent establishment of cuttings in soil. Overall, the established procedure provides a simple and cost-effective means for the rapid propagation of the single-cell C4 species B. sinuspersici.
文摘In forest production systems, vegetative propagation of elite clones through adventitious rooting is a common practice. In Chile, adventitious rooting is the main methodology for vegetative reproduction of Pinus radiata. However, the capability of produce adventitious roots in gymnosperms decreases with aging. While it is true that some efforts have been made to identify markers or/and regulators of the aging process and adventitious rooting, molecular mechanisms that regulate both processes are scarcely known, especially at protein level. This research evaluated qualitative and quantitative changes in protein accumulation during the adventitious rooting process of P. radiata stem cuttings, with different rooting capabilities. Beside, an analysis of morpho-anatomical changes was performed in stem cuttings with high and low rooting capabilities, during the adventitious rooting process. It was observed that juvenile 1-year-old stem cuttings rooted in a 100%, while aged stem cuttings (3-year-old) presented only a 20% of rooting. According to the results of differential protein accumulation, univariate and multivariate analysis indicated that in total, 114 and 89 proteins were differentially accumulated in juvenile and aged cuttings, respectively. Also, identification of such proteins showed the presence of proteins related to cell wall organization and the presence of a protein related with proper distribution of auxin PIN transporter, both key in the new meristem formation process during adventitious rooting.
文摘Polar auxin transport (PAT) is critical in plant growth and development, especially polar differentiation and pattern formation. Lots of studies have been performed in dicots while relative less in monocots. Using two kinds of PAT inhibitors, 2, 3, 5-triiodobenzoic acid (TIBA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA), it was shown that PAT is important for rice (Oryza sativa L. cv. Zhonghua 11) root development, including elongation of the primary roots, initiation and elongation of lateral roots, and formation of adventitious roots. Inhibition of PAT resulted in the shortened primary roots, less and shortened lateral and adventitious roots. Exogenously supplemented NAA can partially rescue the formation of adventitious roots but not lateral roots, while low concentration of NAA (0.1 mumol/L) could not rescue either of them, suggesting the possible different mechanisms of lateral and adventitious root initiations. Treatment of 30 mumol/L TIBA did not completely inhibit the initiation of lateral roots, and survival capacities of which were demonstrated through cross section experiments revealing the presence of primordial of lateral roots at different stages. Further studies through localized application of PAT inhibitors indicated that auxin flow, transported from coleoptiles to the base, is not only responsible for the auxin contents in stem nodes but also critical for initiation and elongation of adventitious roots.
