Conserved exitrons of FLAGELLIN-SENSING 2 (FLS2) across dicot plants and their functions
Conserved exitrons of FLAGELLIN-SENSING 2 (FLS2) across dicot plants and their functions
复制标题
双子叶植物中 FLAGELLIN-SENSING 2 (FLS2) 的保守退出子及其功能
DOI：
10.1016/j.plantsci.2020.110507
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发表时间：
2020-07-01
期刊：
影响因子：
5.2
通讯作者：
Xiong, Qin
中科院分区：
文献类型：
--
作者：
Cheng, Qiang;Xiao, Hongju;Xiong, Qin
模式识别受体基因的选择性剪接调节哺乳动物的免疫信号传导，但在植物中其作用仍不清楚。在这里，我们在九个科的所有受检双子叶植物中的 FLAGELLIN-SENSING 2 (FLS2) 基因的第一个注释外显子中检测到了选择性剪接的内含子（外显子）。 5' 剪接位点 (SS) 区域是保守的，并且具有罕见的同义替换。点突变和基因交换表明退出子剪接的位置和效率主要取决于FLS2基因的核苷酸序列。携带 5'SS 的不变密码子中的单核苷酸突变显着改变了杨树和番茄 FLS2 转录本的积累，表明 FLS2 的 5'-近端退出子在基因表达中充当刺激内含子。杨柳科 FLS2 中退出子的 3' SS 是多种多样的，可以通过 1-2 个核苷酸突变而改变。杨树和烟草FLS2的替代转录物（AT）编码小分泌蛋白，是由flg22特异性诱导的，并且来自烟草FLS2的一种这样的AT抑制flg22诱导的反应。我们的结果表明，FLS2 基因的退出子通过内含子介导的增强（IME）机制调节转录本的积累，并且一些 AT 具有编码 FLS2 通路抑制子的潜力。
The alternative splicing of pattern recognition receptor genes regulates immune signalling in mammals, but in plants its role is still unknown. Here, we detected alternatively spliced introns (exitrons) in the first annotated exons of FLAGELLIN-SENSING 2 (FLS2) genes in all the examined dicot plants across nine families. The 5' splice site (SS) regions were conserved and with rare synonymous substitutions. Point mutations and gene swaps indicated that the position and efficiency of exitron splicing primarily depended on the nucleotide sequences of FLS2 genes. Single-nucleotide mutations in the invariable codon carrying 5' SS dramatically altered the accumulation of poplar and tomato FLS2 transcripts, indicating the 5'-proximal exitrons of FLS2 function as stimulatory introns on gene expression. The 3' SSs of exitrons are diverse and can be changed by 1-2 nucleotide mutations in Salicaceae FLS2. The alternative transcripts (ATs) of poplar and tobacco FLS2, which encode small secreted proteins, were specifically induced by flg22, and one such AT from tobacco FLS2 suppressed flg22-induced response. Our results indicated that the exitrons of FLS2 genes regulate the accumulation of transcripts by an intron mediated enhancement (IME) mechanism and some ATs have the potential to encode suppressors for FLS2 pathway.