紫花苜蓿MsJUB1基因克隆、亚细胞定位及转录自激活分析OA

JUNGBRUNNEN1(JUB1),a member of the NAC transcription factor family,plays a key role in delaying senescence and mediating responses to stress.However,the function in Medicago sativa remains largely unclear.In this study,the MsJUB1 gene was successfully cloned from the alfalfa cultivar GIB.The open reading frame was 936 bp in length and encoded 311 amino acids.Bioinformatics analysis indicated that the protein was a stable hydrophilic protein lacking both a signal peptide and a transmembrane domain.Analysis of cis acting elements showed that the promotor region of MsJUB1 contained multiple stress and hormone responsive elements,including those associated with defense and stress response,abscisic acid,methyl jasmonate,and gibberellin.Subcellular localization analysis demonstrated that MsJUB1 was localized in the nucleus,and yeast two-hybrid assays confirmed that it possessed transcrip-tional autoactivation activity.RT-qPCR analysis further showed that under NaCl treatment,MsJUB1 expression in the roots,stems and leaves of salt tolerant cultivar GIB initially decreased and then increased significantly with prolonged stress exposure.In contrast,expression in the roots and stems of the salt sensi-tive cultivar LS first increased and then declined,whereas expression in the leaves of LS decreased continu-ously over time.These expression patterns suggested that MsJUB1 was involved in salt stress response in M.sativa.