过表达PtrMYB002基因抑制拟南芥生长并提高其抗旱性OA

This study addressed the issue of growth suppression and mortality in poplar caused by increasing global drought,focusing on the R2R3-MYB transcription factor PtrMYB002 from Populus trichocarpa.Utilizing methods including gene cloning,expression vector construction,genetic transformation of Arabidopsis thaliana,and transient transformation in poplar,combined with bioinformatics analysis,subcellular localization,phenotypic observation,physiological index measurement,and gene expression analysis,we investigated its role in regulating plant growth and drought tolerance.The results showed that PtrMYB002 was localized in the nucleus and its expression was significantly induced by drought and ABA treatment.Overexpression of PtrMYB002 gene significantly inhibited the cotyledon area,hypocotyl length,root length,rosette diameter,above-ground fresh mass,and inflorescenced stem height in Arabidopsis,but enhanced its drought tolerance.Under drought conditions,the transgenic lines exhibited significantly higher net CO2 assimilation rate,electron transport rate(ETR),actual photochemical efficiency(Y(Ⅱ)),photochemical quenching coefficient(qP),and non-photochemical quenching coefficient(NPQ),while the stomatal conductance,transpiration rate,and relative electrical conductivity were significantly lower compared to the wild-type(WT).Concurrently,the expression levels of drought-responsive genes AtRD29A and AtDREB2 were significantly upregulated in the transgenic lines.Furthermore,in the'84K'poplar with transient overexpression of PtrMYB002 gene,the expression levels of PagRD29A and PagDREB2B genes were significantly higher than that in the control group,indicating that this regulatory mechanism was likely conserved in poplar.In conclusion,the overexpression of PtrMYB002 gene suppressed growth in Arabidopsis while enhancing its drought tolerance,demonstrating a potential role of the gene in participation of"growth and defense trade-off"strategy,and provided new genetic resources and a theoretical basis for molecular breeding of drought-tolerant poplar.