Response of dehydrin JrDHN gene in walnut to drought stress
[Objective]This purpose was to investigate the physiological and molecular responses,as well as the molecular mechanisms,of Juglans hindsii×J.regia overexpressing line JrDHN during drought stress,to provide theoretical basis for breeding drought-resistant J.regia(walnut)cultivars.[Method]Healthy overexpressing walnut JrDHN were subjected to drought stress at different time points.The response of the overexpressing JrDHN line to drought stress was observed from various aspects including phenotype,antioxidant enzyme activity,and reactive oxygen species content.Quantitative PCR was conducted to analyze the expression levels of drought-related genes MYB,ADH,and CAM in plant tissues,exploring the molecular mechanism by which overexpression of JrDHN gene affects plant drought resistance.[Result]The results confirmed the overexpression of JrDHN gene in walnut seedlings,with expression levels in JrDHN1,2,3 being 2.55,1.72,and 1.49 times higher than the WT respectively.Phenotypic traits of the overexpressing JrDHN line were superior to WT after 1-4 weeks of drought treatment,with significantly lower stomatal aperture in the overexpressing JrDHN line compared to WT after 2 weeks of drought treatment.The activities of antioxidant enzymes(SOD,POD,CAT)showed an initial increase followed by a decrease trend,reaching maximum values at 2 weeks,with SOD and POD activities in JrDHN1 significantly higher than WT(P＜0.01),and CAT activity showing significant difference(P＜0.05).Chlorophyll content reached its minimum after 4 weeks of drought treatment,with significantly higher levels in the overexpressing JrDHN line compared to WT.Levels of MDA,H2O2,and O2·-increased gradually with prolonged drought stress,reaching maximum values at 4 weeks,with significantly lower levels in JrDHN1 compared to WT.Expression levels of drought-related genes MYB,ADH,CAM showed an initial increase followed by a decrease trend,with significantly higher levels in the overexpressing JrDHN line compared to WT after 2 weeks.[Conclusion]The overexpressing JrDHN transgenic walnut seedlings exhibited superior phenotype,photosynthetic capacity,and antioxidant capacity under PEG-simulated drought stress compared to WT.Overexpression of JrDHN gene in walnut seedlings effectively enhanced the activity of antioxidant enzyme system,scavenged reactive oxygen species,reduced cell damage,thereby improving plant drought resistance.[Ch,8 fig.1 tab.34 ref.]
万方数据
维普
