Liu Zhao, Ge Xiaoyang, Yang Zuoren, Zhang Chaojun, Zhao Ge, Chen Eryong, Liu Ji, Zhang Xueyan, Li Fuguang
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
BMC Genet. 2017 Jun 12;18(1):54. doi: 10.1186/s12863-017-0517-3.
Sucrose non-fermenting-1-related protein kinase 2 (SnRK2) is a plant-specific serine/threonine kinase family involved in the abscisic acid (ABA) signaling pathway and responds to osmotic stress. A genome-wide analysis of this protein family has been conducted previously in some plant species, but little is known about SnRK2 genes in upland cotton (Gossypium hirsutum L.). The recent release of the G. hirsutum genome sequence provides an opportunity to identify and characterize the SnRK2 kinase family in upland cotton.
We identified 20 putative SnRK2 sequences in the G. hirsutum genome, designated as GhSnRK2.1 to GhSnRK2.20. All of the sequences encoded hydrophilic proteins. Phylogenetic analysis showed that the GhSnRK2 genes were classifiable into three groups. The chromosomal location and phylogenetic analysis of the cotton SnRK2 genes indicated that segmental duplication likely contributed to the diversification and evolution of the genes. The gene structure and motif composition of the cotton SnRK2 genes were analyzed. Nine exons were conserved in length among all members of the GhSnRK2 family. Although the C-terminus was divergent, seven conserved motifs were present. All GhSnRK2s genes showed expression patterns under abiotic stress based on transcriptome data. The expression profiles of five selected genes were verified in various tissues by quantitative real-time RT-PCR (qRT-PCR). Transcript levels of some family members were up-regulated in response to drought, salinity or ABA treatments, consistent with potential roles in response to abiotic stress.
This study is the first comprehensive analysis of SnRK2 genes in upland cotton. Our results provide the fundamental information for the functional dissection of GhSnRK2s and vital availability for the improvement of plant stress tolerance using GhSnRK2s.
蔗糖非发酵-1相关蛋白激酶2（SnRK2）是植物特有的丝氨酸/苏氨酸激酶家族，参与脱落酸（ABA）信号通路并对渗透胁迫作出响应。此前已在一些植物物种中对该蛋白家族进行了全基因组分析，但对于陆地棉（Gossypium hirsutum L.）中的SnRK2基因了解甚少。陆地棉基因组序列的近期发布为鉴定和表征陆地棉中的SnRK2激酶家族提供了契机。
我们在陆地棉基因组中鉴定出20个假定的SnRK2序列，命名为GhSnRK2.1至GhSnRK2.20。所有序列均编码亲水性蛋白。系统发育分析表明，GhSnRK2基因可分为三组。棉花SnRK2基因的染色体定位和系统发育分析表明，片段重复可能促成了这些基因的多样化和进化。对棉花SnRK2基因的基因结构和基序组成进行了分析。GhSnRK2家族的所有成员中九个外显子的长度是保守的。尽管C端存在差异，但存在七个保守基序。基于转录组数据，所有GhSnRK2s基因在非生物胁迫下均表现出表达模式。通过定量实时RT-PCR（qRT-PCR）在不同组织中验证了五个选定基因的表达谱。一些家族成员的转录水平在干旱、盐度或ABA处理下上调，这与它们在响应非生物胁迫中的潜在作用一致。
本研究是对陆地棉中SnRK2基因的首次全面分析。我们的结果为GhSnRK2s的功能解析提供了基础信息，并为利用GhSnRK2s提高植物胁迫耐受性提供了重要依据。
