In this paper,the fault-tolerant formation control(FTFC)problem is investigated for a group of uncertain nonholonomic mobile robots with limited communication ranges and unpredicted actuator faults,where the communica...In this paper,the fault-tolerant formation control(FTFC)problem is investigated for a group of uncertain nonholonomic mobile robots with limited communication ranges and unpredicted actuator faults,where the communication between the robots is in a directed one-to-one way.In order to guarantee the connectivity preservation and collision avoidance among the robots,some properly chosen performance functions are incorporated into the controller to per-assign the asymmetrical bounds for relative distance and bearing angle between each pair of adjacent mobile robots.Particularly,the resultant control scheme remains at a costeffective level because its design does not use any velocity information from neighbors,any prior knowledge of system nonlinearities or any nonlinear approximator to account for them despite the presence of modeling uncertainties,unknown external disturbances,and unexpected actuator faults.Meanwhile,each follower is derived to track the leader with the tracking errors regarding relative distance and bearing angle subject to prescribed transient and steady-state performance guarantees,respectively.Moreover,all the closed-loop signals are ensured to be ultimately uniformly bounded.Finally,a numerical example is simulated to verify the effectiveness of this methodology.展开更多
As an important spice species in Rutaceae, the Sichuan pepper (Zanthoxylum armatum) can provide pungent and numbing taste, as well as aroma in its mature fruit. Here we assembled a chromosome-level genome of green pri...As an important spice species in Rutaceae, the Sichuan pepper (Zanthoxylum armatum) can provide pungent and numbing taste, as well as aroma in its mature fruit. Here we assembled a chromosome-level genome of green prickly ash which was widely cultivated in a major production area including Chongqing and Sichuan province, China. We generated 712 Gb (~112×) PacBio long reads and 511 Gb (~82×) Hi-C data, and yielded an assembly of 99 pseudochromosomes with total size of 5.32 Gb and contig N50 of 796 kb. The genomic analyses and cytogenetic experiments both indicated that the cultivarZhuye Huajiao’ was a triploid. We identified a Zanthoxylum-specific whole genome duplication event emerging about 24.8 million years ago (Mya). We also detected a transposition burst event (0.3-0.4 Mya) responsible for the large genome size of Z. armatum. Metabolomic analysis of the Zanthoxylum fruits during development stages revealed profiles of39 volatile aroma compounds and 528 secondary metabolites, from which six types of sanshools were identified. Based on metabolomic and transcriptomic network analysis, we screened candidate genes encoding long chain acyl-CoA synthetase, fatty acid desaturase,branched-chain amino acid aminotransferase involved in sanshool biosynthesis and three genes encoding terpene synthase during fruit development. The multi-omics data provide insights into the evolution of Zanthoxylum and molecular basis of numbing and aroma flavor of Sichuan pepper.展开更多
Chlorophylls and carotenoids are essential and bene fi cial substances for both plant and human health.Identifying the regulatory network of these pigments is necessary for improving fruit quality.In a previous study,...Chlorophylls and carotenoids are essential and bene fi cial substances for both plant and human health.Identifying the regulatory network of these pigments is necessary for improving fruit quality.In a previous study,we identi fi ed an R2R3-MYB transcription factor,SlMYB72,that plays an important role in chlorophyll and carotenoid metabolism in tomato fruit.Here,we demonstrated that the SlMYB72-interacting protein SlZHD17,which belongs to the zinc-fi nger homeodomain transcription factor family,also functions in chlorophyll and carotenoid metabolism.Silencing SIZHD 17 in tomato improved multiple bene fi cial agronomic traits,including dwar fi sm,accelerated fl owering,and earlier fruit harvest.More importantly,downregulating SIZHD17 in fruits resulted in larger chloroplasts and a higher chlorophyll content.Dual-luciferase,yeast one-hybrid and electrophoretic mobility shift assays clari fi ed that SlZHD17 regulates the chlorophyll biosynthesis gene SIPOR-B and chloroplast developmental regulator SITKN2 in a direct manner.Chlorophyll degradation and plastid transformation were also retarded after suppression of SIZHD17 in fruits,which was caused by the inhibition of SISGR1,a crucial factor in chlorophyll degradation.On the other hand,the expression of the carotenoid biosynthesis genes SIPSY1 and SIZISO was also suppressed and directly regulated by SlZHD17,which induced uneven pigmentation and decreased the lycopene content in fruits with SIZHD17 suppression at the ripe stage.Furthermore,the protein-protein interactions between SlZHD17 and other pigment regulators,including SlARF4,SlBEL11,and SlTAGL1,were also presented.This study provides new insight into the complex pigment regulatory network and provides new options for breeding strategies aiming to improve fruit quality.展开更多
Flower and fruit abscission is a highly programmed physiological process,which is closely related to the yield of horticultural plants.The coordination of many regulatory factors associated with metabolic and signalin...Flower and fruit abscission is a highly programmed physiological process,which is closely related to the yield of horticultural plants.The coordination of many regulatory factors associated with metabolic and signaling pathways plays a key role in the flower and fruit shedding.Hormones,peptides,carbohydrates,polyamines or cell wall modifying proteins regulate flower and fruit shedding.This article reviewed the recent studies of flower and fruit abscission,including the molecular regulation mechanism of abscission zone formation,typical structure and location of abscission zones,and other factors affecting flower and fruit abscission,such as stresses,hormones,peptides,carbohydrates,polyamines and cell wall modifying proteins.Overall,the review summarizes the developmental mechanism and the diversity of abscission zones,and the key factors affecting flower and fruit abscission of horticultural plants,aiming to provide guidance for studying the molecular regulatory mechanism of flower and fruit abscission.展开更多
Genetic transformation with mature material as the explants could shorten the transgenic period and avoid seed dependence compared with genetic transformation using the epicotyl seedling stem segments as the receptor....Genetic transformation with mature material as the explants could shorten the transgenic period and avoid seed dependence compared with genetic transformation using the epicotyl seedling stem segments as the receptor. Here, we constructed an Agrobacterium tumefaciensmediated transformation for generation of marker-free transgenic plants from navel orange(Citrus sinensis Osbeck) mature stems using a CreloxP recombination system. To efficiently recover the regenerated buds from mature tissues, five recovery methods were compared: in vitro micrografting of 0.1-0.5(1-2 weeks), > 0.5 cm(3-4 weeks) and > 1 cm long lignified bud and in vitro micrografting of explants with a bud and rooting regenerated bud. The data showed that in vitro micrografting of > 1 cm long regenerated bud with expanded leaves after one month of continuous culture for lignification was the optimal solution for plant recovery from mature tissues. Transgenic plants without selectable marker genes were created from navel orange(Citrus sinensis Osbeck) tissue using a transformation vector PLI-35SPR1aCB containing a Cre/loxP system recombination together with genes encoding the selectable marker isopentenyl transferase(IPT) and an anti-bacterial peptide(PR1aCB).Using IPT positive selection, the transformation efficiency determined by PCR was 0.9%, and in total, 20 transgenic plants were obtained.Southern blotting confirmed further their transgenicity. PCR and sequencing analysis demonstrated that both the Cre and IPT genes had been successfully removed from the transgenic plants(deletion efficiency 100%). Over all, using Cre/loxP system recombination together with the IPT positive selection, marker-free transgenic plants can be recovered efficiently from mature tissues of navel orange(Citrus sinensis Osbeck), which provides a potential method for production of transgenic plants from citrus mature tissue.展开更多
The formation and development of pollen are among the most critical processes for reproduction and genetic diversity in the life cycle of f lowering plants.The present study found that SlMYB72 was highly expressed in ...The formation and development of pollen are among the most critical processes for reproduction and genetic diversity in the life cycle of f lowering plants.The present study found that SlMYB72 was highly expressed in the pollen and tapetum of tomato f lowers.Downregulation of SlMYB72 led to a decrease in the amounts of seeds due to abnormal pollen development compared with wild-type plants.Downregulation of SlMYB72 delayed tapetum degradation and inhibited autophagy in tomato anther.Overexpression of SlMYB72 led to abnormal pollen development and delayed tapetum degradation.Expression levels of some autophagy-related genes(ATGs)were decreased in SlMYB72 downregulated plants and increased in overexpression plants.SlMYB72 was directly bound to ACCAAC/ACCAAA motif of the SlATG7 promoter and activated its expression.Downregulation of SlATG7 inhibited the autophagy process and tapetum degradation,resulting in abnormal pollen development in tomatoes.These results indicated SlMYB72 affects the tapetum degradation and pollen development by transcriptional activation of SlATG7 and autophagy in tomato anther.The study expands the understanding of the regulation of autophagy by SlMYB72,uncovers the critical role that autophagy plays in pollen development,and provides potential candidate genes for the production of male-sterility in plants.展开更多
Damage is one of the most important characteristics of rock failure.Studying the damage mechanism of rock blasting under the guiding effect of the water jet slot and revealing the mechanism of controlled blasting with...Damage is one of the most important characteristics of rock failure.Studying the damage mechanism of rock blasting under the guiding effect of the water jet slot and revealing the mechanism of controlled blasting with water jet assistance are crucial.In this study,a rock-like material was chosen as the research object for the calibration experiment of the numerical model.The numerical simulation models were then established by ANSYS/LS-DYNA,and the blastinduced damage mechanism under the guiding effect of the water jet slot was analyzed according to the blasting theory.The results indicated that explosive energy accumulates toward the direction of the slot as the guiding effect of the water jet slot,which allows the rock mass in the direction of the slot bear more damage.Meanwhile,the rock mass in the middle of the connection line between two blast-holes bears more damage under the combination of the effect of the explosion stress wave and guiding effect of water the jet slot on the detonation gas during double-slotted borehole blasting,which results in the formation of a gourd-shaped blast-induced damage area.In addition,the influence of the water jet slot on blast-induced damage varies depending on the blasting-process stage.展开更多
Genetic manipulation of genes to upregulate specific branches of metabolic pathways is a method that is commonly used to improve fruit quality.However,the use of a single gene to impact several metabolic pathways is d...Genetic manipulation of genes to upregulate specific branches of metabolic pathways is a method that is commonly used to improve fruit quality.However,the use of a single gene to impact several metabolic pathways is difficult.Here,we show that overexpression of the single gene SlMYB75(SlMYB75-OE)is effective at improving multiple fruit quality traits.In these engineered fruits,the anthocyanin content reached 1.86mg g−1 fresh weight at the red-ripe stage,and these SlMYB75-OE tomatoes displayed a series of physiological changes,including delayed ripening and increased ethylene production.In addition to anthocyanin,the total contents of phenolics,flavonoids and soluble solids in SlMYB75-OE fruits were enhanced by 2.6,4,and 1.2 times,respectively,compared to those of wild-type(WT)fruits.Interestingly,a number of aroma volatiles,such as aldehyde,phenylpropanoid-derived and terpene volatiles,were significantly increased in SlMYB75-OE fruits,with some terpene volatiles showing more than 10 times higher levels than those in WT fruits.Consistent with the metabolic assessment,transcriptomic profiling indicated that the genes involved in the ethylene signaling,phenylpropanoid and isoprenoid pathways were greatly upregulated in SlMYB75-OE fruits.Yeast one-hybrid and transactivation assays revealed that SlMYB75 is able to directly bind to the MYBPLANT and MYBPZM cis-regulatory elements and to activate the promoters of the LOXC,AADC2 and TPS genes.The identification of SlMYB75 as a key regulator of fruit quality attributes through the transcriptional regulation of downstream genes involved in several metabolic pathways opens new avenues towards engineering fruits with a higher sensory and nutritional quality.展开更多
GRAS proteins are plant-specific transcription factors that play crucial roles in plant development and stress responses.However,their involvement in the ripening of economically important fruits and their transcripti...GRAS proteins are plant-specific transcription factors that play crucial roles in plant development and stress responses.However,their involvement in the ripening of economically important fruits and their transcriptional regulatory mechanisms remain largely unclear.Here,we demonstrated that SlGRAS4,encoding a transcription factor of the GRAS family,was induced by the tomato ripening process and regulated by ethylene.Overexpression of SlGRAS4 accelerated fruit ripening,increased the total carotenoid content and increased PSY1 expression in SlGRAS4-OE fruit compared to wild-type fruit.The expression levels of key ethylene biosynthesis genes(SlACS2,SlACS4,SlACO1,and SlACO3)and crucial ripening regulators(RIN and NOR)were increased in SlGRAS4-OE fruit.The negative regulator of tomato fruit ripening,SlMADS1,was repressed in OE fruit.Exogenous ethylene and 1-MCP treatment revealed that more endogenous ethylene was derived in SlGRAS4-OE fruit.More obvious phenotypes were observed in OE seedlings after ACC treatment.Yeast one-hybrid and dual-luciferase assays confirmed that SlGRAS4 can directly bind SlACO1 and SlACO3 promoters to activate their transcription,and SlGRAS4 can also directly repress SlMADS1 expression.Our study identified that SlGRAS4 acts as a new regulator of fruit ripening by regulating ethylene biosynthesis genes in a direct manner.This provides new knowledge of GRAS transcription factors involved in regulating fruit ripening.展开更多
Auxin response factors(ARFs)are involved in auxin-mediated transcriptional regulation in plants.In this study,we performed functional characterization of SlARF6A in tomato.SlARF6A is located in the nucleus and exhibit...Auxin response factors(ARFs)are involved in auxin-mediated transcriptional regulation in plants.In this study,we performed functional characterization of SlARF6A in tomato.SlARF6A is located in the nucleus and exhibits transcriptional activator activity.Overexpression of SlARF6A increased chlorophyll contents in the fruits and leaves of tomato plants,whereas downregulation of SlARF6A decreased chlorophyll contents compared with those of wild-type(WT)plants.Analysis of chloroplasts using transmission electron microscopy indicated increased sizes of chloroplasts in SlARF6A-overexpressing plants and decreased numbers of chloroplasts in SlARF6A-downregulated plants.Overexpression of SlARF6A increased the photosynthesis rate and accumulation of starch and soluble sugars,whereas knockdown of SlARF6A resulted in opposite phenotypes in tomato leaves and fruits.RNA-sequence analysis showed that regulation of SlARF6A expression altered the expression of genes involved in chlorophyll metabolism,photosynthesis and sugar metabolism.SlARF6A directly bound to the promoters of SlGLK1,CAB,and RbcS genes and positively regulated the expression of these genes.Overexpression of SlARF6A also inhibited fruit ripening and ethylene production,whereas downregulation of SlARF6A increased fruit ripening and ethylene production.SlARF6A directly bound to the SAMS1 promoter and negatively regulated SAMS1 expression.Taken together,these results expand our understanding of ARFs with regard to photosynthesis,sugar accumulation and fruit development and provide a potential target for genetic engineering to improve fruit nutrition in horticulture crops.展开更多
CRISPR/Cas9-induced genome editing is a powerful tool for studying gene function in a variety of organisms,including plants.Using multi-sgRNAs to target one or more genes is helpful to improve the efficacy of gene edi...CRISPR/Cas9-induced genome editing is a powerful tool for studying gene function in a variety of organisms,including plants.Using multi-sgRNAs to target one or more genes is helpful to improve the efficacy of gene editing and facilitate multi-gene editing.Here,we describe a CRISPR/Cas9 system which can be conveniently developed as a CRISPR kit.SgRNA expression cassettes can be rapidly generated by one-step PCR using our CRISPR kit.In our kit,there are two binary vectors pHNCas9 and pHNCas9HT.The binary vector pHNCas9 was constructed to allow to assemble up to eight sgRNA expression cassettes by one-step Golden Gate cloning.Another binary vector pHNCas9HT can be used to generate a large number of single target constructs by directly transforming ligation reactions products into A.tumefaciens without several procedures,such as PCR and plasmid extraction.The two binary vectors are designed according to the principles of standard BioBrick assembly to be used as an open-source tool.For example,we used BioBrick as a visual T-DNA tag.We also developed a primer design aid to complement the system.With this primer design aid,researchers can rapidly obtain primers and GC content,and sgRNA sequence of target site.Our CRISPR/Cas9 system can perform single-and multi-site editing and multiple gene editing to produce various types of mutations in tomato.This rapid and user-friendly CRISPR/Cas9 system for tomato can be potentially used for mutagenesis of important crop species for genetic improvement and is suitable for research into the function of genes.展开更多
Abscission,a cell separation process,is an important trait that in fluences grain and fruit yield.We previously reported that BEL1-LIKE HOMEODOMAIN 4(SIBL4)is involved in chloroplast development and cell wall metaboli...Abscission,a cell separation process,is an important trait that in fluences grain and fruit yield.We previously reported that BEL1-LIKE HOMEODOMAIN 4(SIBL4)is involved in chloroplast development and cell wall metabolism in tomato fruit.In the present study,we showed that silencing SIBL4 resulted in the enlargement and pre-abscission of the tomato(Solanum lycopersicum cv.Micro-TOM)fruit pedicel.The anatomic analysis showed the presence of more epidermal cell layers and no obvious abscission zone(AZ)in the SlBL4 RNAi lines compared with the wild-type plants.RNA-seq analysis indicated that the regulation of abscission by SlBL4 was associated with the altered abundance of genes related to key meristems,auxin transporters,signaling components,and cell wall metabolism.Furthermore,SlBL4 positively affected the auxin concentration in the abscission zone.A dual-luciferase reporter assay revealed that SlBL4 activated the transcription of the JOINTLESS,OVATE,PIN1,and LAX3 genes.We reported a novel function ofSlBL4,which plays key roles in fruit pedicel organogenesis and abscission in tomatoes.展开更多
As a class of powerful molecular tool,antisense oligonucleotides(ASOs)are not only broadly used in protein and RNA biology,but also a highly selective therapeutic strategy for many diseases.Although the concept that A...As a class of powerful molecular tool,antisense oligonucleotides(ASOs)are not only broadly used in protein and RNA biology,but also a highly selective therapeutic strategy for many diseases.Although the concept that ASO reagents only reduce expression of the targeted gene in a post-transcriptional manner has long been established,the effect and mechanism of ASO reagents on RNA polymerase II(Pol II)transcription are largely unknown.This raised question is particularly important for the appropriate use of ASOs and the valid interpretation of ASO-mediated experiments.In this study,our results show that linear RNA ASO attenuates transcription of nascent transcripts by inducing premature transcription termination which is combinatorially controlled by Integrator,exosome,and Rat1 in Drosophila.However,circular RNA(circRNA)ASO transfection does not affect transcription activity of the encoded gene.These data suggest that the ASO technique can be applied to study a circRNA-mediated but not linear RNA-mediated function for its encoded gene locus.展开更多
Maize is an essential source of nutrition for humans and animals and is rich in various metabolites that determine its quality.Different maize varieties show significant differences in metabolite content.Two kinds of ...Maize is an essential source of nutrition for humans and animals and is rich in various metabolites that determine its quality.Different maize varieties show significant differences in metabolite content.Two kinds of waxy maize parental materials,S181 and 49B,created by the Chongqing Academy of Agricultural Sciences,are widely grown in China.S181 shows higher starch and sugar contents than 49B.This study generated metabolic profiles to assess the differences between the two varieties.A total of 674 metabolites that were significantly differentially expressed between the two varieties were identified by gas chromatography and untargeted metabolomics technology.These metabolites were associated with 21 categories,including antioxidant metabolites.Moreover,6415 differentially expressed genes(DEGs)were identified by RNA-seq.Interestingly,these DEGs comprised starch and sugar synthesis pathway genes and 72 different transcription factor families.Among these,six families that were reported to play an essential role in plant antioxidant action accounted for 39.2%of the transcription factor families.Using the Kyoto Encyclopedia of Genes and Genomes(KEGG)classification,the DEGs were mainly involved in amino acid biosynthesis,glycolysis/glucose metabolism,and the synthetic and metabolic pathways of antioxidant active substances.Furthermore,the correlation analysis of transcriptome and metabolomics identified five key transcription factors(ZmbHLH172,ZmNAC44,ZmNAC-like18,ZmS1FA2,ZmERF172),one ubiquitin ligase gene(ZmE25A)and one sucrose synthase gene(ZmSS1).They likely contribute to the quality traits of waxy corn through involvement in the metabolic regulatory network of antioxidant substances.Thus,our results provide new insights into maize quality-related antioxidant metabolite networks and have potential applications for waxy corn breeding.展开更多
Object servoing is becoming more and more important for service robots. Because of the nonholonomicconstraints of a differential-drive service robot and the possibly changed pose of amovable object, it is challenging ...Object servoing is becoming more and more important for service robots. Because of the nonholonomicconstraints of a differential-drive service robot and the possibly changed pose of amovable object, it is challenging to design an object servoing scheme for the differential-driveservice robot such that it can asymptotically park at a predefined relative pose to that of the movableobject. In this paper, a novel object servoing scheme is proposed for the differential-driveservice robots using switched control. Each relative online pose is first estimated by using featuresof the movable object, the estimated pose is an input of an object servoing friendly parkingcontroller. The linear velocity and angular speed are then determined by the proposed controller.Simulation results validate the performance of the proposed object servoing scheme. Due to itslow online computational cost, the proposed scheme can be applied for the real-time tasks ofdifferential-drive service robots to movable objects.展开更多
The ethylene response factors(ERFs)belong to the APETALA2/ethylene response factor(AP2/ERF)superfamily and act downstream of the ethylene signalling pathway to regulate the expression of ethylene responsive genes.In d...The ethylene response factors(ERFs)belong to the APETALA2/ethylene response factor(AP2/ERF)superfamily and act downstream of the ethylene signalling pathway to regulate the expression of ethylene responsive genes.In different species,ERFs have been reported to be involved in plant development,flower abscission,fruit ripening,and defense responses.In this review,based on the new progress made by recent studies,we summarize the specific role and mode of action of ERFs in regulating different aspects of ripening in both climacteric and non-climacteric fruits,and provide new insights into the role of ethylene in non-climacteric fruit ripening.展开更多
基金supported in part by the National KeyResearch and Development Program of China under Grant 2021ZD0201300Fundamental Research Funds for the Central Universities under Project 2021CDJXKJC001in part by the Chongqing Human Resources and Social Security Bureau under Grant cx2021114.
文摘In this paper,the fault-tolerant formation control(FTFC)problem is investigated for a group of uncertain nonholonomic mobile robots with limited communication ranges and unpredicted actuator faults,where the communication between the robots is in a directed one-to-one way.In order to guarantee the connectivity preservation and collision avoidance among the robots,some properly chosen performance functions are incorporated into the controller to per-assign the asymmetrical bounds for relative distance and bearing angle between each pair of adjacent mobile robots.Particularly,the resultant control scheme remains at a costeffective level because its design does not use any velocity information from neighbors,any prior knowledge of system nonlinearities or any nonlinear approximator to account for them despite the presence of modeling uncertainties,unknown external disturbances,and unexpected actuator faults.Meanwhile,each follower is derived to track the leader with the tracking errors regarding relative distance and bearing angle subject to prescribed transient and steady-state performance guarantees,respectively.Moreover,all the closed-loop signals are ensured to be ultimately uniformly bounded.Finally,a numerical example is simulated to verify the effectiveness of this methodology.
基金supported by the Projects for Innovative Research Groups of Chongqing Universities (Grant No.CXQT21028)Chongqing talent program for Zexiong Chen+2 种基金Scientific Technological Research Program of Chongqing Municipal Education Commission (Grant No.KJZD-K201901303)National Natural Science Foundation of China (Grant No.31925034)National Key Research and Development Project (Grant No.2019YFD1001200)。
文摘As an important spice species in Rutaceae, the Sichuan pepper (Zanthoxylum armatum) can provide pungent and numbing taste, as well as aroma in its mature fruit. Here we assembled a chromosome-level genome of green prickly ash which was widely cultivated in a major production area including Chongqing and Sichuan province, China. We generated 712 Gb (~112×) PacBio long reads and 511 Gb (~82×) Hi-C data, and yielded an assembly of 99 pseudochromosomes with total size of 5.32 Gb and contig N50 of 796 kb. The genomic analyses and cytogenetic experiments both indicated that the cultivarZhuye Huajiao’ was a triploid. We identified a Zanthoxylum-specific whole genome duplication event emerging about 24.8 million years ago (Mya). We also detected a transposition burst event (0.3-0.4 Mya) responsible for the large genome size of Z. armatum. Metabolomic analysis of the Zanthoxylum fruits during development stages revealed profiles of39 volatile aroma compounds and 528 secondary metabolites, from which six types of sanshools were identified. Based on metabolomic and transcriptomic network analysis, we screened candidate genes encoding long chain acyl-CoA synthetase, fatty acid desaturase,branched-chain amino acid aminotransferase involved in sanshool biosynthesis and three genes encoding terpene synthase during fruit development. The multi-omics data provide insights into the evolution of Zanthoxylum and molecular basis of numbing and aroma flavor of Sichuan pepper.
基金This work was sponsored by the National Natural Science Foundation of China(No.32002100,31772370,31972470).
文摘Chlorophylls and carotenoids are essential and bene fi cial substances for both plant and human health.Identifying the regulatory network of these pigments is necessary for improving fruit quality.In a previous study,we identi fi ed an R2R3-MYB transcription factor,SlMYB72,that plays an important role in chlorophyll and carotenoid metabolism in tomato fruit.Here,we demonstrated that the SlMYB72-interacting protein SlZHD17,which belongs to the zinc-fi nger homeodomain transcription factor family,also functions in chlorophyll and carotenoid metabolism.Silencing SIZHD 17 in tomato improved multiple bene fi cial agronomic traits,including dwar fi sm,accelerated fl owering,and earlier fruit harvest.More importantly,downregulating SIZHD17 in fruits resulted in larger chloroplasts and a higher chlorophyll content.Dual-luciferase,yeast one-hybrid and electrophoretic mobility shift assays clari fi ed that SlZHD17 regulates the chlorophyll biosynthesis gene SIPOR-B and chloroplast developmental regulator SITKN2 in a direct manner.Chlorophyll degradation and plastid transformation were also retarded after suppression of SIZHD17 in fruits,which was caused by the inhibition of SISGR1,a crucial factor in chlorophyll degradation.On the other hand,the expression of the carotenoid biosynthesis genes SIPSY1 and SIZISO was also suppressed and directly regulated by SlZHD17,which induced uneven pigmentation and decreased the lycopene content in fruits with SIZHD17 suppression at the ripe stage.Furthermore,the protein-protein interactions between SlZHD17 and other pigment regulators,including SlARF4,SlBEL11,and SlTAGL1,were also presented.This study provides new insight into the complex pigment regulatory network and provides new options for breeding strategies aiming to improve fruit quality.
基金funded by the National Natural Science Foundation of China(Grant Nos.31972470,32002100,31772370)Key research and development project of Sichuan Provincial Science and Technology Department(Grant No.2021YFQ0071)。
文摘Flower and fruit abscission is a highly programmed physiological process,which is closely related to the yield of horticultural plants.The coordination of many regulatory factors associated with metabolic and signaling pathways plays a key role in the flower and fruit shedding.Hormones,peptides,carbohydrates,polyamines or cell wall modifying proteins regulate flower and fruit shedding.This article reviewed the recent studies of flower and fruit abscission,including the molecular regulation mechanism of abscission zone formation,typical structure and location of abscission zones,and other factors affecting flower and fruit abscission,such as stresses,hormones,peptides,carbohydrates,polyamines and cell wall modifying proteins.Overall,the review summarizes the developmental mechanism and the diversity of abscission zones,and the key factors affecting flower and fruit abscission of horticultural plants,aiming to provide guidance for studying the molecular regulatory mechanism of flower and fruit abscission.
基金supported by the Fundamental Research Funds for the Central Universities (Grant No. XDJK 2018B016)the National Natural Sciences Foundation of China (Grant No. 31972393)+1 种基金he earmarked fund for China Agriculture Research System (Grant No. CARS-26)the Natural Science Foundation of Chongqing (Grant No. cstc2020jcyj-msxmX1064)。
文摘Genetic transformation with mature material as the explants could shorten the transgenic period and avoid seed dependence compared with genetic transformation using the epicotyl seedling stem segments as the receptor. Here, we constructed an Agrobacterium tumefaciensmediated transformation for generation of marker-free transgenic plants from navel orange(Citrus sinensis Osbeck) mature stems using a CreloxP recombination system. To efficiently recover the regenerated buds from mature tissues, five recovery methods were compared: in vitro micrografting of 0.1-0.5(1-2 weeks), > 0.5 cm(3-4 weeks) and > 1 cm long lignified bud and in vitro micrografting of explants with a bud and rooting regenerated bud. The data showed that in vitro micrografting of > 1 cm long regenerated bud with expanded leaves after one month of continuous culture for lignification was the optimal solution for plant recovery from mature tissues. Transgenic plants without selectable marker genes were created from navel orange(Citrus sinensis Osbeck) tissue using a transformation vector PLI-35SPR1aCB containing a Cre/loxP system recombination together with genes encoding the selectable marker isopentenyl transferase(IPT) and an anti-bacterial peptide(PR1aCB).Using IPT positive selection, the transformation efficiency determined by PCR was 0.9%, and in total, 20 transgenic plants were obtained.Southern blotting confirmed further their transgenicity. PCR and sequencing analysis demonstrated that both the Cre and IPT genes had been successfully removed from the transgenic plants(deletion efficiency 100%). Over all, using Cre/loxP system recombination together with the IPT positive selection, marker-free transgenic plants can be recovered efficiently from mature tissues of navel orange(Citrus sinensis Osbeck), which provides a potential method for production of transgenic plants from citrus mature tissue.
基金supported by the National Natural Science Foundation of China(32172596)the Technology Innovation and Application Development Project in Chongqing(cstc2021jscxcylhX0115)+3 种基金the Chongqing Talents Innovation Leading Talents Project(cstc2022ycjh-bgzxm0018)the Tianfu Scholar Program of Sichuan Province(Department of Human Resources and Social Security of Sichuan Province 2021-58)d the Fundamental Research Funds for the Central Universities(2021CDJZYJH002)The Graduate Research and Innovation Foundation of Chongqing,China(CYB22048).
文摘The formation and development of pollen are among the most critical processes for reproduction and genetic diversity in the life cycle of f lowering plants.The present study found that SlMYB72 was highly expressed in the pollen and tapetum of tomato f lowers.Downregulation of SlMYB72 led to a decrease in the amounts of seeds due to abnormal pollen development compared with wild-type plants.Downregulation of SlMYB72 delayed tapetum degradation and inhibited autophagy in tomato anther.Overexpression of SlMYB72 led to abnormal pollen development and delayed tapetum degradation.Expression levels of some autophagy-related genes(ATGs)were decreased in SlMYB72 downregulated plants and increased in overexpression plants.SlMYB72 was directly bound to ACCAAC/ACCAAA motif of the SlATG7 promoter and activated its expression.Downregulation of SlATG7 inhibited the autophagy process and tapetum degradation,resulting in abnormal pollen development in tomatoes.These results indicated SlMYB72 affects the tapetum degradation and pollen development by transcriptional activation of SlATG7 and autophagy in tomato anther.The study expands the understanding of the regulation of autophagy by SlMYB72,uncovers the critical role that autophagy plays in pollen development,and provides potential candidate genes for the production of male-sterility in plants.
基金support for this work was provided by the Sichuan Natural Science Foundation Project(Youth Science Foundation Project)(No.2022NSFSC1089)the Natural Science Foundation of Southwest University of Science and Technology(No.18zx7124).
文摘Damage is one of the most important characteristics of rock failure.Studying the damage mechanism of rock blasting under the guiding effect of the water jet slot and revealing the mechanism of controlled blasting with water jet assistance are crucial.In this study,a rock-like material was chosen as the research object for the calibration experiment of the numerical model.The numerical simulation models were then established by ANSYS/LS-DYNA,and the blastinduced damage mechanism under the guiding effect of the water jet slot was analyzed according to the blasting theory.The results indicated that explosive energy accumulates toward the direction of the slot as the guiding effect of the water jet slot,which allows the rock mass in the direction of the slot bear more damage.Meanwhile,the rock mass in the middle of the connection line between two blast-holes bears more damage under the combination of the effect of the explosion stress wave and guiding effect of water the jet slot on the detonation gas during double-slotted borehole blasting,which results in the formation of a gourd-shaped blast-induced damage area.In addition,the influence of the water jet slot on blast-induced damage varies depending on the blasting-process stage.
基金supported by the National Key Research and Development Program(2016YFD0400101)the National Natural Science Foundation of China(31572175,31772370)+1 种基金the Fundamental Research Funds for the Central Universities(2018CDXYSM0021)the Committee of Science and Technology of Chongqing(cstckjcxljrc15).
文摘Genetic manipulation of genes to upregulate specific branches of metabolic pathways is a method that is commonly used to improve fruit quality.However,the use of a single gene to impact several metabolic pathways is difficult.Here,we show that overexpression of the single gene SlMYB75(SlMYB75-OE)is effective at improving multiple fruit quality traits.In these engineered fruits,the anthocyanin content reached 1.86mg g−1 fresh weight at the red-ripe stage,and these SlMYB75-OE tomatoes displayed a series of physiological changes,including delayed ripening and increased ethylene production.In addition to anthocyanin,the total contents of phenolics,flavonoids and soluble solids in SlMYB75-OE fruits were enhanced by 2.6,4,and 1.2 times,respectively,compared to those of wild-type(WT)fruits.Interestingly,a number of aroma volatiles,such as aldehyde,phenylpropanoid-derived and terpene volatiles,were significantly increased in SlMYB75-OE fruits,with some terpene volatiles showing more than 10 times higher levels than those in WT fruits.Consistent with the metabolic assessment,transcriptomic profiling indicated that the genes involved in the ethylene signaling,phenylpropanoid and isoprenoid pathways were greatly upregulated in SlMYB75-OE fruits.Yeast one-hybrid and transactivation assays revealed that SlMYB75 is able to directly bind to the MYBPLANT and MYBPZM cis-regulatory elements and to activate the promoters of the LOXC,AADC2 and TPS genes.The identification of SlMYB75 as a key regulator of fruit quality attributes through the transcriptional regulation of downstream genes involved in several metabolic pathways opens new avenues towards engineering fruits with a higher sensory and nutritional quality.
基金the Natural Science Foundation of Chongqing,China(cstc2019jcyj-bshX0008 to Y.L.)funding provided by the National Key Research and Development Program(2016YFD0400101)the National Natural Science Foundation of China(No.31772370,31972470)to Z.L.
文摘GRAS proteins are plant-specific transcription factors that play crucial roles in plant development and stress responses.However,their involvement in the ripening of economically important fruits and their transcriptional regulatory mechanisms remain largely unclear.Here,we demonstrated that SlGRAS4,encoding a transcription factor of the GRAS family,was induced by the tomato ripening process and regulated by ethylene.Overexpression of SlGRAS4 accelerated fruit ripening,increased the total carotenoid content and increased PSY1 expression in SlGRAS4-OE fruit compared to wild-type fruit.The expression levels of key ethylene biosynthesis genes(SlACS2,SlACS4,SlACO1,and SlACO3)and crucial ripening regulators(RIN and NOR)were increased in SlGRAS4-OE fruit.The negative regulator of tomato fruit ripening,SlMADS1,was repressed in OE fruit.Exogenous ethylene and 1-MCP treatment revealed that more endogenous ethylene was derived in SlGRAS4-OE fruit.More obvious phenotypes were observed in OE seedlings after ACC treatment.Yeast one-hybrid and dual-luciferase assays confirmed that SlGRAS4 can directly bind SlACO1 and SlACO3 promoters to activate their transcription,and SlGRAS4 can also directly repress SlMADS1 expression.Our study identified that SlGRAS4 acts as a new regulator of fruit ripening by regulating ethylene biosynthesis genes in a direct manner.This provides new knowledge of GRAS transcription factors involved in regulating fruit ripening.
基金supported by the National Key R&D Program of China(2016YFD0400100)the Project of Chongqing Science and Technology Commission(CSTC2015JCYJA80018)the National Natural Science Foundation of China(31272165).
文摘Auxin response factors(ARFs)are involved in auxin-mediated transcriptional regulation in plants.In this study,we performed functional characterization of SlARF6A in tomato.SlARF6A is located in the nucleus and exhibits transcriptional activator activity.Overexpression of SlARF6A increased chlorophyll contents in the fruits and leaves of tomato plants,whereas downregulation of SlARF6A decreased chlorophyll contents compared with those of wild-type(WT)plants.Analysis of chloroplasts using transmission electron microscopy indicated increased sizes of chloroplasts in SlARF6A-overexpressing plants and decreased numbers of chloroplasts in SlARF6A-downregulated plants.Overexpression of SlARF6A increased the photosynthesis rate and accumulation of starch and soluble sugars,whereas knockdown of SlARF6A resulted in opposite phenotypes in tomato leaves and fruits.RNA-sequence analysis showed that regulation of SlARF6A expression altered the expression of genes involved in chlorophyll metabolism,photosynthesis and sugar metabolism.SlARF6A directly bound to the promoters of SlGLK1,CAB,and RbcS genes and positively regulated the expression of these genes.Overexpression of SlARF6A also inhibited fruit ripening and ethylene production,whereas downregulation of SlARF6A increased fruit ripening and ethylene production.SlARF6A directly bound to the SAMS1 promoter and negatively regulated SAMS1 expression.Taken together,these results expand our understanding of ARFs with regard to photosynthesis,sugar accumulation and fruit development and provide a potential target for genetic engineering to improve fruit nutrition in horticulture crops.
基金supported by the National Key Research and Development Program of China(2016YFD0400101),the National Basic Research Program of China(2013CB127101)the National Natural Science Foundation of China(31572175,31401924)the Project of Chongqing Science and Technology Commission(cstckjcxljrc15).
文摘CRISPR/Cas9-induced genome editing is a powerful tool for studying gene function in a variety of organisms,including plants.Using multi-sgRNAs to target one or more genes is helpful to improve the efficacy of gene editing and facilitate multi-gene editing.Here,we describe a CRISPR/Cas9 system which can be conveniently developed as a CRISPR kit.SgRNA expression cassettes can be rapidly generated by one-step PCR using our CRISPR kit.In our kit,there are two binary vectors pHNCas9 and pHNCas9HT.The binary vector pHNCas9 was constructed to allow to assemble up to eight sgRNA expression cassettes by one-step Golden Gate cloning.Another binary vector pHNCas9HT can be used to generate a large number of single target constructs by directly transforming ligation reactions products into A.tumefaciens without several procedures,such as PCR and plasmid extraction.The two binary vectors are designed according to the principles of standard BioBrick assembly to be used as an open-source tool.For example,we used BioBrick as a visual T-DNA tag.We also developed a primer design aid to complement the system.With this primer design aid,researchers can rapidly obtain primers and GC content,and sgRNA sequence of target site.Our CRISPR/Cas9 system can perform single-and multi-site editing and multiple gene editing to produce various types of mutations in tomato.This rapid and user-friendly CRISPR/Cas9 system for tomato can be potentially used for mutagenesis of important crop species for genetic improvement and is suitable for research into the function of genes.
基金the National Natural Science Foundation of China(31601763 and 31972470)the Inner Mon golia Univer sity High-Level Tale nt Research Program(12000-15031934).
文摘Abscission,a cell separation process,is an important trait that in fluences grain and fruit yield.We previously reported that BEL1-LIKE HOMEODOMAIN 4(SIBL4)is involved in chloroplast development and cell wall metabolism in tomato fruit.In the present study,we showed that silencing SIBL4 resulted in the enlargement and pre-abscission of the tomato(Solanum lycopersicum cv.Micro-TOM)fruit pedicel.The anatomic analysis showed the presence of more epidermal cell layers and no obvious abscission zone(AZ)in the SlBL4 RNAi lines compared with the wild-type plants.RNA-seq analysis indicated that the regulation of abscission by SlBL4 was associated with the altered abundance of genes related to key meristems,auxin transporters,signaling components,and cell wall metabolism.Furthermore,SlBL4 positively affected the auxin concentration in the abscission zone.A dual-luciferase reporter assay revealed that SlBL4 activated the transcription of the JOINTLESS,OVATE,PIN1,and LAX3 genes.We reported a novel function ofSlBL4,which plays key roles in fruit pedicel organogenesis and abscission in tomatoes.
基金the Natural Science Foundation of Chongqing,China(cstc2019jcyj-msxmX0085)the Innovation Support Program for Overseas Returned Scholars of Chongqing,China(cx2019142)+1 种基金the Fundamental Research Funds for the Central Universities of China(2020CDJQY-A076)the 100 Talent Program of Chongqing University(0304001104433)。
文摘As a class of powerful molecular tool,antisense oligonucleotides(ASOs)are not only broadly used in protein and RNA biology,but also a highly selective therapeutic strategy for many diseases.Although the concept that ASO reagents only reduce expression of the targeted gene in a post-transcriptional manner has long been established,the effect and mechanism of ASO reagents on RNA polymerase II(Pol II)transcription are largely unknown.This raised question is particularly important for the appropriate use of ASOs and the valid interpretation of ASO-mediated experiments.In this study,our results show that linear RNA ASO attenuates transcription of nascent transcripts by inducing premature transcription termination which is combinatorially controlled by Integrator,exosome,and Rat1 in Drosophila.However,circular RNA(circRNA)ASO transfection does not affect transcription activity of the encoded gene.These data suggest that the ASO technique can be applied to study a circRNA-mediated but not linear RNA-mediated function for its encoded gene locus.
基金supported by the General Program of Natural Science Foundation of Chongqing(cstc2019jcyj msxmx0468)Chongqing Talents Program—Basic Research and Frontier Exploration(cstc2021ycjh bgzxm0152)+1 种基金Chongqing Agricultural Development Fund Project—Resource Plant New Variety Breeding and Application(NKY-2020AB015)the Fundamental Research Funds for the Central Universities(2022CDJXY-004),China.
文摘Maize is an essential source of nutrition for humans and animals and is rich in various metabolites that determine its quality.Different maize varieties show significant differences in metabolite content.Two kinds of waxy maize parental materials,S181 and 49B,created by the Chongqing Academy of Agricultural Sciences,are widely grown in China.S181 shows higher starch and sugar contents than 49B.This study generated metabolic profiles to assess the differences between the two varieties.A total of 674 metabolites that were significantly differentially expressed between the two varieties were identified by gas chromatography and untargeted metabolomics technology.These metabolites were associated with 21 categories,including antioxidant metabolites.Moreover,6415 differentially expressed genes(DEGs)were identified by RNA-seq.Interestingly,these DEGs comprised starch and sugar synthesis pathway genes and 72 different transcription factor families.Among these,six families that were reported to play an essential role in plant antioxidant action accounted for 39.2%of the transcription factor families.Using the Kyoto Encyclopedia of Genes and Genomes(KEGG)classification,the DEGs were mainly involved in amino acid biosynthesis,glycolysis/glucose metabolism,and the synthetic and metabolic pathways of antioxidant active substances.Furthermore,the correlation analysis of transcriptome and metabolomics identified five key transcription factors(ZmbHLH172,ZmNAC44,ZmNAC-like18,ZmS1FA2,ZmERF172),one ubiquitin ligase gene(ZmE25A)and one sucrose synthase gene(ZmSS1).They likely contribute to the quality traits of waxy corn through involvement in the metabolic regulatory network of antioxidant substances.Thus,our results provide new insights into maize quality-related antioxidant metabolite networks and have potential applications for waxy corn breeding.
文摘Object servoing is becoming more and more important for service robots. Because of the nonholonomicconstraints of a differential-drive service robot and the possibly changed pose of amovable object, it is challenging to design an object servoing scheme for the differential-driveservice robot such that it can asymptotically park at a predefined relative pose to that of the movableobject. In this paper, a novel object servoing scheme is proposed for the differential-driveservice robots using switched control. Each relative online pose is first estimated by using featuresof the movable object, the estimated pose is an input of an object servoing friendly parkingcontroller. The linear velocity and angular speed are then determined by the proposed controller.Simulation results validate the performance of the proposed object servoing scheme. Due to itslow online computational cost, the proposed scheme can be applied for the real-time tasks ofdifferential-drive service robots to movable objects.
基金This research was supported by the National Key R&D Program of China(2016YFD0400100)the National Natural Science Foundation of China(31772372).
文摘The ethylene response factors(ERFs)belong to the APETALA2/ethylene response factor(AP2/ERF)superfamily and act downstream of the ethylene signalling pathway to regulate the expression of ethylene responsive genes.In different species,ERFs have been reported to be involved in plant development,flower abscission,fruit ripening,and defense responses.In this review,based on the new progress made by recent studies,we summarize the specific role and mode of action of ERFs in regulating different aspects of ripening in both climacteric and non-climacteric fruits,and provide new insights into the role of ethylene in non-climacteric fruit ripening.
