长链非编码RNA LincRNA12879调控ABA介导的干旱胁迫应答机制研究

The phytohormone abscisic acid (ABA) plays an important role in abiotic stress response and tolerance of plants. In contrast with the role of protein-coding genes in plant ABA response pathway which has been well investigated, the role of lncRNA in plant ABA responses is unclear. To understand the ABA-dependent signal transduction mechanism in response to drought, we performed a genetic screen to isolate mutants defected in ABA responses from the lncRNA mutant library of Arabidopsis thaliana. We identified a novel lncRNA, lincRNA12879, which modulates plant responses to ABA and drought stress. The lincRNA12879 mutants not only showed markedly reduced sensitivity to ABA, but also showed hypersensitivity to drought stress. Furthermore, lincRNA12879 mainly enriched in nucleus, and it can affect the expression of neighboring gene At3g62500. Therefore, we propose that lincRNA12879 participates in plant responses to ABA and drought stress through cis-regulating At3g62500. We will functionally characterize the lincRNA12879 by combining genetic, physiology, biochemistry, bioinformatics and transcriptome approaches. Our findings will provide novel insights into molecular mechanism of lncRNA regulated gene expression in the process of plant ABA and abiotic stress response.

脱落酸（ABA）是一种重要的植物激素，在植物对非生物胁迫应答与抗逆性方面发挥着重要作用。相对于研究比较完善的参与植物ABA应答的蛋白基因，长链非编码RNA（lncRNA）在ABA应答中的作用研究较少。我们前期以拟南芥lncRNA突变体库为材料筛选ABA反应突变体时，鉴定到一个新的lncRNA，lincRNA12879，该lncRNA突变体不仅对ABA的敏感性减弱，且抗旱性也降低。另外还发现lincRNA12879的转录本主要富集于细胞核中，并且它能影响其相邻基因At3g62500的表达。因此推测lincRNA12879可能通过顺式调控其旁邻基因的表达来参与植物对ABA与干旱胁迫的应答。我们将通过遗传分析，并结合生理学、生物化学和高通量测序等手段深入研究lincRNA12879的功能。本项目研究成果对于理解非编码RNA在植物ABA与非生物胁迫应答过程中调控基因表达的分子机制有重要意义。

干旱是限制植物生长和影响农作物产量的重要非生物胁迫因素。植物体内许多长链非编码RNA（lncRNA）对外界胁迫极为敏感并调控植物对环境胁迫的适用，然而关于lncRNA调控植物干旱胁迫应答的机制尚不清楚。本研究以前期筛选到的对干旱胁迫敏感的长链非编码RNA突变体lincRNA12879入手，综合利用遗传学与分子生物学等手段，深入研究了lincRNA12879的生物学功能和作用机制。取得了以下结果：.1、表型分析发现lincRNA12879缺失突变体的气孔张合度要大于野生型且失水速率明显加快，这表明lincRNA12879通过调节拟南芥叶片的气孔张合度来减少蒸腾作用从而正调控植物干旱胁迫应答。.2、转录组测序分析发现在lincRNA12879突变体中有多个与干旱胁迫相关的基因的表达量发生改变。其中干旱胁迫正调控因子ANAC055与ATRZPF34在lincRNA12879突变体中表达下调，这表明lincRNA12879可通过调控其靶基因ANAC055与ATRZPF34的表达来影响植物干旱胁迫应答。.3、利用酵母三杂交技术筛选到3个与lincRNA12879相互作用的蛋白PABN1、PABN2与PABN3，它们都属于多腺苷酸结合蛋白。表型分析发现PABN1、PABN2和PABN3功能缺失均会导致拟南芥气孔张合度增大和失水速率加快，这表明这3个蛋白也是通过调节植物叶片的气孔张合度来参与调控拟南芥干旱胁迫应答。.4、lincRNA12879通过与多腺苷酸结合蛋白PABN1，PABN2与PABN3相互作用来影响植物干旱胁迫应答正调控因子ANAC055的转录与可变多聚腺苷酸化，从而正调控植物干旱胁迫应答。.本项目解析lincRNA12879在植物干旱胁迫应答过程中的功能与分子机制，丰富了植物干旱胁迫信号网络，同时也对研究植物中lncRNA的功能与机制有重要借鉴意义。.