Cre-miR171在柑橘响应干旱胁迫中的作用

Effect of Cre-miR171 on Drought Stress Response in Citrus

干旱是影响柑橘生产的一个重要因素.为探究Cre-miR171在柑橘耐旱中的作用,本研究对其前体上游启动子顺式作用元件进行了分析,研究了其在柑橘组织及生长发育时期的表达特征,验证了Cre-miR171在柑橘中的靶基因,评价了干旱胁迫下Cre-miR171及其靶基因在根不同部位的表达模式,以及过表达Cre-miR171的拟南芥和柑橘的耐旱性.结果表明,Cre-miR171前体序列启动子区具有与应答及调控逆境胁迫相关的多种响应元件.在根发育的早期高表达,在侧根发生区的表达量高于根尖.通过生物信息分析及组织表达相关分析鉴定到了3个靶基因,CclSCL6,CclSCL22和CclSCL26,并利用烟草瞬时表达试验证实了这3个靶基因与Cre-miR171的靶向关系.在为期15 d的干旱胁迫处理中,Cre-miR171在侧根区和根尖的表达在处理的第10 d出现了明显的相反趋势,在根尖上调表达,在侧根区下调表达,3个靶基因的表达也呈现相应的变化.过表达Cre-miR171的拟南芥和柑橘对干旱的敏感性显著高于对照,过表达Cre-miR171的柑橘主根的伸长生长和侧根的发生受到了抑制.以上结果表明,Cre-miR171能影响柑橘根的伸长生长和侧根发生,负调控柑橘的耐旱性.

Drought is an important environmental factor affecting the citrus production.In order to explore the role of Cre-miR171 in citrus drought tolerance,this study analyzed the cis-acting elements of its precursor upstream promoter,studied the expression characteristics in different citrus tissues,and growth and development stages,verified the target genes of Cre-miR171,and evaluated the expression patterns of Cre-miR171 and its target genes in different parts of roots under drought stress,as well as the drought tolerance of Cre-miR171 overexpression Arabidopsis and citrus plants.The results showed that the promoter region of Cre-miR171 precursor sequence has a variety of elements related to regulation of stress response.Cre-miR171 was highly expressed in the early stage of root development,and the expression level in the lateral root area was higher than that in the root tip.Through bioinformatics analysis and tissue expression correlation analysis,three target genes,CclSCL6,CclSCL22 and CclSCL26,were identified.The targeting relationship between these three target genes and Cre-miR171 was confirmed by tobacco transient expression experiments.In a 15-day drought stress treatment,the expression of Cre-miR171 in the lateral root zone and root tip showed a significant opposite trend from the 10th day of treatment with up-regulated expression in the root tip and down-regulated expression in the lateral root zone.The expression of the three target genes also showed corresponding changes.The sensitivity of Arabidopsis and citrus plants overexpressing Cre-miR171 to drought was significantly higher than that of the control,and the elongation growth of main roots and the generation of lateral roots in citrus were inhibited.The above results indicated that Cre-miR171 can affect the elongation growth and lateral root formation,and negatively regulate the drought tolerance in citrus.