Drought tolerance levels and antioxidant protection mechanisms were evaluated for 21 traditional rice varieties of Assam, India, along with Sahbhagi Dhan （drought tolerant） and IR64 （drought sensitive） as controls...Drought tolerance levels and antioxidant protection mechanisms were evaluated for 21 traditional rice varieties of Assam, India, along with Sahbhagi Dhan （drought tolerant） and IR64 （drought sensitive） as controls. Drought was imposed in hydroponic culture with polyethylene glycol 6000 （PEG6000） that was initially standardized with different concentrations. All the rice varieties showed apparent decreases in growth characteristics under drought stress （initially at 15% for 7 d followed by 20% PEG6000 for 7 d in Yoshida medium）. On the basis of standard evaluation score （SES）, eight rice varieties showed high drought tolerance which were carried forward for further biochemical analyses. Based on different morpho- physiological parameters, SN03 （Bora）, SN04 （Prosad Bhog）, SN05 （Kola Joha）, SN06 （Helash Bora）, SN08 （Salihoi Bao）, SN12 （Kola Amona）, SN20 （Ronga Bora） and SN21 （Sok-Bonglong） were identified as promising drought tolerant varieties. The non-enzymatic antioxidants activities viz., glutathione, ascorbate and enzymatic antioxidant activities such as superoxide dismutase （SOD）, catalase （CAT）, guaiacol peroxidase （GPX）, ascorbate peroxidase （APX）, glutathione reductase （GR） in shoots and roots of all the selected varieties revealed significant level of protection mechanisms as compared with controls. Enhancement in activities of the overall antioxidant enzymes including SOD, GPX, CAT, GR and APX under drought stress reflects their role in the adaptation process under water stress.展开更多
Tea (Camellia sinensis) is one of the most important economic crops. Being perennial in nature, tea plant often experiences natural drought, which affects its growth and productivity. The present investigation was und...Tea (Camellia sinensis) is one of the most important economic crops. Being perennial in nature, tea plant often experiences natural drought, which affects its growth and productivity. The present investigation was undertaken to understand the mechanism of post-drought stress recovery on rehydration and the effect of nutrients in the recovery process of the selected clones of Camellia sinensis L. (TV-1, TV-20, TV-29 & TV-30). The results demonstrated that decrease in relative water content (RWC), dry mass of leaf and antioxidants like-ascorbate and glutathione in all the tested clones, as a result of imposed water stress, which caused damage was not permanent. Increase in phenolic content with decrease in O2-, H2O2 and lipid peroxidation was indication of the recovery of stress induced oxidative damage following the post stress rehydration. Further, the post drought recovery was enhanced by foliar spray of K, Ca, Mn & B. Differential activities of enzymes like SOD, CAT, POX, GR and PPO in response to foliar spray of nutrients in rehydrated plant improved the recovery process. The present study reveals that the tested nutrients (K, Ca, Mn & B) showed some positive response in influencing growth and antioxidative responses during post drought recovery process, where K and Ca showed comparatively better effect in improving post drought recovery potential in tea plant.展开更多
NAC(NAM/ATAF1/2/CUC2)transcription factors are central switches of growth and stress responses in plants.However,unpredictable interspecies conservation of function and regulatory targets makes the well-studied NAC or...NAC(NAM/ATAF1/2/CUC2)transcription factors are central switches of growth and stress responses in plants.However,unpredictable interspecies conservation of function and regulatory targets makes the well-studied NAC orthologs inapt for pulse engineering.The knowledge of suitable NAC candidates in hardy pulses like cowpea(Vigna unguiculata(L.)Walp.)is still in infancy,hence warrants immediate biotechnological intervention.Here,we showed that overexpression of two native NAC genes(VuNAC1and VuNAC2)promoted germinative,vegetative,and reproductive growth and conferred multiple abiotic stress tolerance in a commercial cowpea variety.The transgenic lines displayed increased leaf area,thicker stem,nodule-rich denser root system,early flowering,higher pod production(~3.2-fold and~2.1-fold),and greater seed weight(10.3%and 6.0%).In contrast,transient suppression of VuNAC1/2 caused severe growth retardation and flower inhibition.The overexpressor lines showed remarkable tolerance to major yielddeclining terminal stresses,such as drought,salinity,heat,and cold,and recovered growth and seed production by boosting photosynthetic activity,water use efficiency,membrane integrity,Na^(+)/K^(+)homeostasis,and antioxidant activity.The comparative transcriptome study indicated consolidated activation of genes involved in chloroplast development,photosynthetic complexes,cell division and expansion,cell wall biogenesis,nutrient uptake and metabolism,stress response,abscisic acid,and auxin signaling.Unlike their orthologs,VuNAC1/2 direct synergistic transcriptional tuning of stress and developmental signaling to avoid unwanted trade-offs.Their overexpression governs the favorable interplay of photosynthesis and reactive oxygen species regulation to improve stress recovery,nutritional sufficiency,biomass,and production.This unconventional balance of strong stress tolerance and agronomic quality is useful for translational crop research and molecular breeding of pulses.展开更多
Hydrogen peroxide （H202） is a reactive oxygen species that affects cell signaling in various plant defense responses and induces programmed cell death. To identify the new components associated with H202 signaling a...Hydrogen peroxide （H202） is a reactive oxygen species that affects cell signaling in various plant defense responses and induces programmed cell death. To identify the new components associated with H202 signaling and tolerance, we conducted a genome-wide association study （GWAS） on the root growth of 133 Arabidopsis thaliana accessions grown in the presence of toxic H2O2 levels. The most significant SNPs were associated with a cluster of chromosome 4 genes encoding an aquaporin NODULIN 26-LIKE INTRINSIC PROTEIN 1; 1 （NIP1;1）, an NB-ARC domain-containing disease resistance protein （AT4G19050）, and a putative membrane lipoprotein （AT4G19070）. The expression level of NIP1;1 was relatively high in A. thaliana accessions sensitive to H2O2. Additionally, overexpression of NIP1;1 in a tolerant accession （e.g., Col-0） increased the sensitivity of transgenic plants to H2O2. An in planta β-glucuronidase reporter assay revealed that variations in the NIP1;1 promoter were responsible for the differences of its expression level in H2O2-tolerant and -sensitive accessions. Cell death was extensive and H2O2 levels were high in the roots of H2O2-sensitive and NIP1;1-overexpressing accessions. Together, our results indicate that the aquaporin NIP1;1 is a key determinant of the sensitivity ofA. thaliana to H2O2, and contributes to the phenotypic variations detected by our GWAS.展开更多
Biochar is a carbon-rich material obtained after thermochemical conversion of biomass under no oxygen environment.The effect of biochar amendment on soil properties,such as water retention,infiltration and desiccation...Biochar is a carbon-rich material obtained after thermochemical conversion of biomass under no oxygen environment.The effect of biochar amendment on soil properties,such as water retention,infiltration and desiccation crack potential was studied in the recent years.However,the effect of biochar or feedstock type on these properties is not explicit.This study investigates the effect of two different(in terms of feedstock)types of biochar on the water retention,infiltration and desiccation crack-ing behavior of compacted silty sand.Water retention characteristics,infiltration rate and the progression of desiccation cracks were measured after compacting soil amended with 5-10%(w/w)biochar produced from water hyacinth(WHB)and mesquite.Measurements were also taken for an unpyrolyzed material coir pith(CP,sourced from coconut husk)-amended soil for comparing the results of biochar-amended soil.The results show that the amendment of 5%to 10%biochar increased the maximum water holding capacity(θs),air entry value(AEV)and water content at 1500 kPa(θ1500)of the soil,whereas decreased the infiltration rate and peak crack intensity factor(CIF)of the soil.Moreover,the application of CP increased the infiltration rate.The amendment of WHB showed the highest increment in AEV andθ1500 and the highest decrement in infiltration rate and CIF compared to the other amendments.Based on the results,it is advisable to use the WHB-amended soil in bioengineered structures that could promote the growth of vegetation by higher water retention and could reduce the potential of leachate formation by decreasing water infiltration and desiccation crack potential.展开更多
基金supported by UGC,Maulana Azad National Fellowship for Minority Students,Government of India
文摘Drought tolerance levels and antioxidant protection mechanisms were evaluated for 21 traditional rice varieties of Assam, India, along with Sahbhagi Dhan （drought tolerant） and IR64 （drought sensitive） as controls. Drought was imposed in hydroponic culture with polyethylene glycol 6000 （PEG6000） that was initially standardized with different concentrations. All the rice varieties showed apparent decreases in growth characteristics under drought stress （initially at 15% for 7 d followed by 20% PEG6000 for 7 d in Yoshida medium）. On the basis of standard evaluation score （SES）, eight rice varieties showed high drought tolerance which were carried forward for further biochemical analyses. Based on different morpho- physiological parameters, SN03 （Bora）, SN04 （Prosad Bhog）, SN05 （Kola Joha）, SN06 （Helash Bora）, SN08 （Salihoi Bao）, SN12 （Kola Amona）, SN20 （Ronga Bora） and SN21 （Sok-Bonglong） were identified as promising drought tolerant varieties. The non-enzymatic antioxidants activities viz., glutathione, ascorbate and enzymatic antioxidant activities such as superoxide dismutase （SOD）, catalase （CAT）, guaiacol peroxidase （GPX）, ascorbate peroxidase （APX）, glutathione reductase （GR） in shoots and roots of all the selected varieties revealed significant level of protection mechanisms as compared with controls. Enhancement in activities of the overall antioxidant enzymes including SOD, GPX, CAT, GR and APX under drought stress reflects their role in the adaptation process under water stress.
文摘Tea (Camellia sinensis) is one of the most important economic crops. Being perennial in nature, tea plant often experiences natural drought, which affects its growth and productivity. The present investigation was undertaken to understand the mechanism of post-drought stress recovery on rehydration and the effect of nutrients in the recovery process of the selected clones of Camellia sinensis L. (TV-1, TV-20, TV-29 & TV-30). The results demonstrated that decrease in relative water content (RWC), dry mass of leaf and antioxidants like-ascorbate and glutathione in all the tested clones, as a result of imposed water stress, which caused damage was not permanent. Increase in phenolic content with decrease in O2-, H2O2 and lipid peroxidation was indication of the recovery of stress induced oxidative damage following the post stress rehydration. Further, the post drought recovery was enhanced by foliar spray of K, Ca, Mn & B. Differential activities of enzymes like SOD, CAT, POX, GR and PPO in response to foliar spray of nutrients in rehydrated plant improved the recovery process. The present study reveals that the tested nutrients (K, Ca, Mn & B) showed some positive response in influencing growth and antioxidative responses during post drought recovery process, where K and Ca showed comparatively better effect in improving post drought recovery potential in tea plant.
基金supported by a research grant from the Program Support Grant Phase-II from the Department of Biotechnology,Government of India to L.S. (BT/PR13560/COE/34/44/2015)。
文摘NAC(NAM/ATAF1/2/CUC2)transcription factors are central switches of growth and stress responses in plants.However,unpredictable interspecies conservation of function and regulatory targets makes the well-studied NAC orthologs inapt for pulse engineering.The knowledge of suitable NAC candidates in hardy pulses like cowpea(Vigna unguiculata(L.)Walp.)is still in infancy,hence warrants immediate biotechnological intervention.Here,we showed that overexpression of two native NAC genes(VuNAC1and VuNAC2)promoted germinative,vegetative,and reproductive growth and conferred multiple abiotic stress tolerance in a commercial cowpea variety.The transgenic lines displayed increased leaf area,thicker stem,nodule-rich denser root system,early flowering,higher pod production(~3.2-fold and~2.1-fold),and greater seed weight(10.3%and 6.0%).In contrast,transient suppression of VuNAC1/2 caused severe growth retardation and flower inhibition.The overexpressor lines showed remarkable tolerance to major yielddeclining terminal stresses,such as drought,salinity,heat,and cold,and recovered growth and seed production by boosting photosynthetic activity,water use efficiency,membrane integrity,Na^(+)/K^(+)homeostasis,and antioxidant activity.The comparative transcriptome study indicated consolidated activation of genes involved in chloroplast development,photosynthetic complexes,cell division and expansion,cell wall biogenesis,nutrient uptake and metabolism,stress response,abscisic acid,and auxin signaling.Unlike their orthologs,VuNAC1/2 direct synergistic transcriptional tuning of stress and developmental signaling to avoid unwanted trade-offs.Their overexpression governs the favorable interplay of photosynthesis and reactive oxygen species regulation to improve stress recovery,nutritional sufficiency,biomass,and production.This unconventional balance of strong stress tolerance and agronomic quality is useful for translational crop research and molecular breeding of pulses.
文摘Hydrogen peroxide （H202） is a reactive oxygen species that affects cell signaling in various plant defense responses and induces programmed cell death. To identify the new components associated with H202 signaling and tolerance, we conducted a genome-wide association study （GWAS） on the root growth of 133 Arabidopsis thaliana accessions grown in the presence of toxic H2O2 levels. The most significant SNPs were associated with a cluster of chromosome 4 genes encoding an aquaporin NODULIN 26-LIKE INTRINSIC PROTEIN 1; 1 （NIP1;1）, an NB-ARC domain-containing disease resistance protein （AT4G19050）, and a putative membrane lipoprotein （AT4G19070）. The expression level of NIP1;1 was relatively high in A. thaliana accessions sensitive to H2O2. Additionally, overexpression of NIP1;1 in a tolerant accession （e.g., Col-0） increased the sensitivity of transgenic plants to H2O2. An in planta β-glucuronidase reporter assay revealed that variations in the NIP1;1 promoter were responsible for the differences of its expression level in H2O2-tolerant and -sensitive accessions. Cell death was extensive and H2O2 levels were high in the roots of H2O2-sensitive and NIP1;1-overexpressing accessions. Together, our results indicate that the aquaporin NIP1;1 is a key determinant of the sensitivity ofA. thaliana to H2O2, and contributes to the phenotypic variations detected by our GWAS.
文摘Biochar is a carbon-rich material obtained after thermochemical conversion of biomass under no oxygen environment.The effect of biochar amendment on soil properties,such as water retention,infiltration and desiccation crack potential was studied in the recent years.However,the effect of biochar or feedstock type on these properties is not explicit.This study investigates the effect of two different(in terms of feedstock)types of biochar on the water retention,infiltration and desiccation crack-ing behavior of compacted silty sand.Water retention characteristics,infiltration rate and the progression of desiccation cracks were measured after compacting soil amended with 5-10%(w/w)biochar produced from water hyacinth(WHB)and mesquite.Measurements were also taken for an unpyrolyzed material coir pith(CP,sourced from coconut husk)-amended soil for comparing the results of biochar-amended soil.The results show that the amendment of 5%to 10%biochar increased the maximum water holding capacity(θs),air entry value(AEV)and water content at 1500 kPa(θ1500)of the soil,whereas decreased the infiltration rate and peak crack intensity factor(CIF)of the soil.Moreover,the application of CP increased the infiltration rate.The amendment of WHB showed the highest increment in AEV andθ1500 and the highest decrement in infiltration rate and CIF compared to the other amendments.Based on the results,it is advisable to use the WHB-amended soil in bioengineered structures that could promote the growth of vegetation by higher water retention and could reduce the potential of leachate formation by decreasing water infiltration and desiccation crack potential.
