中山杉不定根发育相关基因ThEIN3的克隆及初步功能分析OA

Taxodium hybrid'Zhongshanshan'relies on softwood cutting for asexual propagation.Elucidating the molecular mechanism of its adventitious root(AR)development and identifying key genes are of great significance for establishing an efficient genetic transformation system and improving propagation efficiency.To investigate the function of ethylene-insensitive 3(EIN3),a core transcription factor in the ethylene(ET)signal transduction pathway of T.hybrid'Zhongshanshan',during AR development,the ThEIN3 gene(GenBank No.PX209540)was cloned in this study.Its function was identified by overexpressing ThEIN3 in tobacco(Nicotiana benthamiana)through an Agrobacterium tumefacien-mediated expression system.The results showed that the full-length ThEIN3 gene was 2 073 bp,encoding 690 amino acids.It contained a typical conserved domain of the EIN3 superfamily and was localized in the nucleus.With the development of AR in T.hybrid'Zhongshanshan',the expression level of ThEIN3 was gradually down-regulated,and its expression in mature soft shoots was significantly higher than that in rejuvenated soft shoots(P＜0.05).Compared with wild-type tobacco(WT),the AR development of ThEIN3-overexpressing plants was inhibited.Hormone content measurements at the base of adventitious roots revealed a significant increase in the content of gibberellin A3(GA3)(P＜0.05),while the contents of indole-3-acetic acid(IAA)and trans-zeatin riboside(TZR)decreased.Further research on the molecular mechanism indicated that ThEIN3 might inhibit the occurrence of AR by coordinating key genes in the related hormone metabolism pathways.This study provides a foundation for further research on the regulatory mechanisms of AR development in T.hybrid'Zhongshanshan'and offers genetic resources and theoretical guidance for its molecular breeding.