棉花OSCA基因家族全基因组鉴定及耐盐耐旱功能验证

摘要：棉花为纺织制造业提供了最多的天然纤维，但由于受土壤高盐环境的影响，其产量正在下降。OSCA（Hyperosmdality-gate calcium-permeable channels）参与感知细胞外渗透势的变化，从而诱导Ca2+浓度增加，调节渗透势。为了解棉花OSCA基因的特征和功能，本研究全基因组分析对棉花 OSCA 基因家族。在陆地棉、亚洲棉、雷蒙德氏棉中分别鉴定出35、21、22个OSCA基因成员，并根据其基因结构和系统发育关系分为4个不同的组。基因和蛋白质结构分析表明，35个GhOSCA家族基因均含有保守的RSN1_7TM（PF02714，DUF221）结构域。顺式作用元件分析表明，OSCA基因家族成员可能在响应热、低温、干旱、盐胁迫等方面发挥关键作用。通过RNA-seq和qRT-PCR分析表明，GhOSCA基因在不同组织的表达具有特异性，这表明GhOSCA家族成员在不同组织中发挥特定的作用来调节渗透压。GhOSCA1.1与AtOSCA1最为相似，在盐和干旱胁迫下表达显著上调，表明GhOSCA1.1可能是一个参与盐和干旱胁迫反应的关键基因。通过病毒诱导基因沉默（VIGS）技术分析了GhOSCA1.1的潜在功能。在干旱和盐胁迫下，与对照和空载相比，沉默植株均表现出严重萎蔫的现象。GhOSCA1.1基因沉默植株与空载植株相比，SOD活性和PRO含量降低，MDA含量升高，植株的耐旱耐盐性减弱，证明该基因是参与耐旱耐盐应答的关键基因。本研究对棉花OSCA基因家族进行系统分析，对于了解OSCA基因在棉花中编码蛋白质的功能具有重要意义，为进一步研究OSCA基因所发挥的分子作用奠定了基础，从而为盐和干旱胁迫条件下提高作物抗性提供了理论基础。

关键词：OSCA基因家族；陆地棉；VIGS；盐和干旱胁迫

作者：杨秀，许艳超，杨芳芳，MAGWANGA Richard Odongo，蔡小彦，王星星，王玉红，侯宇清，王坤波，刘方，周忠丽

[Background] Cotton (Gossypium hirsutum) provides the largest natural fiber for the textile manufacturing industries, but its production is on the decline due to the effects of salinity. Soil salt-alkalization leads to damage in cotton growth and a decrease in yields. Hyperosmolality-gated calcium-permeable channels (OSCA) have been found to be involved in the detection of extracellular changes which trigger an increase in cytosolic free calcium concentration. Hyperosmolality-induced calcium ion increases have been widely speculated to be playing a role in osmosensing in plants. However, the molecular nature of the corresponding calcium ion channels remains unclearly. In this research work, we describe the OSCA genes and their putative function in osmosensing in plants by carrying out genome-wide identification, characterization and functional analysis of the significantly up-regulated OSCA gene, GhOSCA1.1 through reverse genetics.

[Results] A total of 35, 21 and 22 OSCA genes were identified in G. hirsutum, G. arboreum, and G. raimondii genomes, respectively, and were classified into four different clades according to their gene structure and phylogenetic relationship. Gene and protein structure analysis indicated that 35 GhOSCA genes contained a conserved RSN1_7TM (PF02714) domain. Moreover, the cis-regulatory element analysis indicated that the OSCA genes were involved in response to abiotic stress. Furthermore, the knockdown of one of the highly up-regulated genes, Gh_OSCA1.1 showed that the virus-induced gene silenced (VIGS) plants were highly sensitive to dehydration and salinity stresses compared with the none VIGS plants as evident with higher concentration levels of oxidant enzymes compared with the antioxidant enzymes on the leaves of the stressed plants.

[Conclusions] This study provides the first systematic analysis of the OSCA gene family and will be important for understanding the putative functions of the proteins encoded by the OSCA genes in cotton. These results provide a new insight of defense responses in general and lay the foundation for further investigation of the molecular role played by the OSCA genes, thereby providing suitable approaches to improve crop performance under salinity and drought stress conditions.

[Title] Genome-wide identification of OSCA gene family and their potential function in the regulation of dehydration and salt stress inGossypium hirsutum

[Authors] Xiu YANG, Yanchao XU, Fangfang YANG, Richard Odongo MAGWANGA, Xiaoyan CAI, Xingxing WANG, Yuhong WANG, Yuqing HOU, Kunbo WANG, Fang LIU & Zhongli ZHOU

Journal of Cotton Research. 2019; 2:11

https://doi.org/10.1186/s42397-019-0028-z

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0028-z