ARR21基因在拟南芥生长发育和离体再生过程中的功能分析

Functional Analysis of the ARR21 Gene in Arabidopsis thaliana during Growth and Development and in Vitro Regeneration

为了揭示细胞分裂素信号途径关键因子ARR21的功能,对拟南芥中B型ARR家族基因进行进化关系分析,通过构建ARR21基因过表达和缺失突变体,分析该基因在调控幼苗生长发育和离体再生中的作用。结果表明,拟南芥中编码12个B型ARR,其中,ARR21和ARR13亲缘关系较近;过量表达ARR21基因以及缺失DDK结构域后组成型表达ARR21均严重阻碍了幼苗的生长发育,表现为根系较短,真叶不能伸展;而arr21、arr13单突变体和arr13/21双突变体幼苗生长发育完全正常。进一步离体再生结果表明,过量表达ARR21ΔDDK基因可显著提高离体再生效率,但ARR21基因功能缺失对离体再生无显著影响,arr13单突变体和arr13/21双突变体离体再生效率均低于野生型,暗示ARR13和ARR21基因可能存在功能冗余。研究结果可为进一步解析细胞分裂素信号转导途径在植物生长发育和离体再生过程中的功能奠定基础。

To explore the function of ARR21,a key factor of cytokinin signaling pathway,the paper analyzed the evolutionary relationship between the type-B ARR genes in Arabidopsis thaliana,and the role of ARR21 gene in regulating seedling growth and in vitro regeneration by constructing overexpression and deletion mutants of ARR21.The results showed that there were 12 type-B ARRs in Arabidopsis thaliana among which ARR21 and ARR13 were closely related.Both overexpression of ARR21 and constitutive expression of ARR21 without DDK domain severely hindered the growth and development of seedlings.Those mutants'root system was short and true leaves could not extend.But the growth and development of seedlings in arr21 single mutant,arr13 single mutant and arr13/21 double mutant were completely normal.In addition,the function of ARR21 gene in vitro regeneration was further analyzed,and the results showed that overexpression of ARR21ΔDDK gene significantly increased in vitro regeneration efficiency,but the deletion mutant arr21 had no significant effect on in vitro regeneration efficiency.In vitro regeneration efficiency of arr13 and arr13/21 were lower than that of wild type,suggesting that there might be functional redundancy in ARR13 and ARR21 genes.This study result will lay a foundation for further understanding the function of cytokinin signal transduction pathway in plant growth and development and in vitro regeneration.