SAUR41 亚家族的 SMALL AUXIN UP RNA 基因是脱落酸诱导的，可调节拟南芥幼苗的细胞扩张和耐盐性。
The SAUR41 subfamily of SMALL AUXIN UP RNA genes is abscisic acid inducible to modulate cell expansion and salt tolerance in Arabidopsis thaliana seedlings.
机构信息
Institute of Genetics and Regenerative Biology, College of Life Sciences, Zhejiang University, Hangzhou, China.
出版信息
Ann Bot. 2020 Apr 25;125(5):805-819. doi: 10.1093/aob/mcz160.
BACKGROUND AND AIMS
Most primary auxin response genes are classified into three families: AUX/IAA, GH3 and SAUR genes. Few studies have been conducted on Arabidopsis thaliana SAUR genes, possibly due to genetic redundancy among different subfamily members. Data mining on arabidopsis transcriptional profiles indicates that the SAUR41 subfamily members of SMALL AUXIN UP RNA genes are, strikingly, induced by an inhibitory phytohormone, abscisic acid (ABA). We aimed to reveal the physiological roles of arabidopsis SAUR41 subfamily genes containing SAUR40, SAUR41, SAUR71 and SAUR72.
METHODS
Transcriptional responses of arabidopsis SAUR41 genes to phytohormones were determined by quantitative real-time PCR. Knock out of SAUR41 genes was carried out with the CRISPR/Cas9 (clustered regulatory interspaced short palindromic repeats/CRISPR-associated protein 9) genome editing technique. The saur41/40/71/72 quadruple mutants, SAUR41 overexpression lines and the wild type were subjected to ultrastructural observation, transcriptome analysis and physiological characterization.
KEY RESULTS
Transcription of arabidopsis SAUR41 subfamily genes is activated by ABA but not by gibberellic acids and brassinosteroids. Quadruple mutations in saur41/40/71/72 led to reduced cell expansion/elongation in cotyledons and hypocotyls, opposite to the overexpression of SAUR41; however, an irregular arrangement of cell size and shape was observed in both cases. The quadruple mutants had increased transcription of calcium homeostasis/signalling genes in seedling shoots, and the SAUR41 overexpression lines had decreased transcription of iron homeostasis genes in roots and increased ABA biosynthesis in shoots. Notably, both the quadruple mutants and the SAUR41 overexpression lines were hypersensitive to salt stress during seedling establishment, whereas specific expression of SAUR41 under the ABA-responsive RD29A (Responsive to Desiccation 29A) promoter in the quadruple mutants rescued the inhibitory effect of salt stress.
CONCLUSIONS
The SAUR41 subfamily genes of arabidopsis are ABA inducible to modulate cell expansion, ion homeostasis and salt tolerance. Our work may provide new candidate genes for improvement of plant abiotic stress tolerance.
背景与目的
大多数初级生长素响应基因分为三类：AUX/IAA、GH3 和 SAUR 基因。由于不同亚家族成员之间存在遗传冗余，因此对拟南芥 SAUR 基因的研究较少。对拟南芥转录谱的数据挖掘表明，SMALL AUXIN UP RNA 基因的 SAUR41 亚家族成员显著受到抑制性植物激素脱落酸（ABA）的诱导。我们旨在揭示包含 SAUR40、SAUR41、SAUR71 和 SAUR72 的拟南芥 SAUR41 亚家族基因的生理作用。
方法
通过定量实时 PCR 确定拟南芥 SAUR41 基因对植物激素的转录反应。使用 CRISPR/Cas9（成簇规律间隔短回文重复/CRISPR 相关蛋白 9）基因组编辑技术敲除 SAUR41 基因。对 saur41/40/71/72 四重突变体、SAUR41 过表达系和野生型进行超微结构观察、转录组分析和生理特性分析。
主要结果
拟南芥 SAUR41 亚家族基因的转录被 ABA 激活，但不受赤霉素和油菜素内酯的影响。saur41/40/71/72 四重突变导致子叶和下胚轴的细胞扩张/伸长减少，与 SAUR41 的过表达相反；然而，两种情况下都观察到细胞大小和形状的不规则排列。四重突变体在幼苗茎中的钙稳态/信号转导基因的转录增加，而 SAUR41 过表达系在根中的铁稳态基因的转录减少，在茎中的 ABA 生物合成增加。值得注意的是，在幼苗建立过程中，四重突变体和 SAUR41 过表达系都对盐胁迫敏感，而在四重突变体中 ABA 响应 RD29A（响应干旱 29A）启动子下的 SAUR41 特异性表达挽救了盐胁迫的抑制作用。
结论
拟南芥的 SAUR41 亚家族基因被 ABA 诱导以调节细胞扩张、离子稳态和耐盐性。我们的工作可能为提高植物非生物胁迫耐受性提供新的候选基因。
Zotero 插件