荔枝HSP70家族鉴定及其响应非生物胁迫的表达分析

Identification and expression analysis of the HSP70 gene family under abiotic stresses in Litchi chinensis

摘要:

HSP70蛋白作为热激蛋白(heat shock protein, HSP)家族重要成员之一，在植物的生长发育、逆境胁迫等过程中发挥着重要作用。为探究荔枝(Litchi chinensis) HSP70基因家族成员在应对低温、高温、干旱及盐胁迫环境时的作用，利用生物信息学方法鉴定荔枝全基因组中的HSP70基因家族，并通过实时荧光定量PCR (quantitative real-time PCR, qRT-PCR)技术检测HSP70家族成员在不同非生物胁迫处理下的表达模式。结果显示，LcHSP70基因家族共包含18个成员，不均匀地分布在荔枝的10条染色体上，其蛋白包含479-851个不等的氨基酸，等电点介于5.07-6.95之间，分子质量为52.44-94.07 kDa。LcHSP70蛋白在细胞核、细胞质、内质网、线粒体和叶绿体中有分布。系统进化分析发现LcHSP70蛋白分布在5个亚族，分别为Ⅰ、Ⅱ、Ⅲ、Ⅳ和Ⅵ亚族。LcHSP70s启动子区域拥有多种与植物生长发育、激素响应及逆境响应相关的顺式作用元件。转录组数据分析显示，LcHSP70s存在明显的组织表达特异性，总体上可分为普遍性表达和特异性表达。非生物胁迫表达分析显示，该基因家族成员均可以对低温、高温、干旱和盐胁迫作出不同程度的反应，且在不同时间表达差异显著。上述研究结果为进一步探究荔枝HSP70基因家族的功能奠定了基础。

Abstract:

HSP70 protein, as an important member of the heat shock protein (HSP) family, plays an important role in plant growth, development, and response to biotic and abiotic stresses. In order to explore the role of HSP70 gene family members in Litchi chinensis under low temperature, high temperature, drought, and salt stress, bioinformatics methods were used to identify the HSP70 gene family members within the entire L. chinensis genome. The expression of these genes under various abiotic stresses was then detected using quantitative real-time PCR (qRT-PCR). The results showed that the LcHSP70 gene family consisted of 18 members, which were unevenly distributed across ten L. chinensis chromosomes. The LcHSP70 protein contained 479-851 amino acids, with isoelectric points ranging from 5.07 to 6.95, and molecular weights from 52.44 kDa to 94.07 kDa. The predicted subcellular localization showed that LcHSP70 protein was present in the nucleus, cytoplasm, endoplasmic reticulum, mitochondria, and chloroplast. Phylogenetic analysis divided the LcHSP70 proteins into five subgroups, namely Ⅰ, Ⅱ, Ⅲ, Ⅳ, and Ⅵ. The promoter regions of the LcHSP70 genes contained various cis-acting elements related to plant growth, development, hormone response, and stress response. Moreover, the expression of LcHSP70 genes displayed distint tissue-specific expression level, categorized into universal expression and specific expression. From the selected 6 LcHSP70 genes (i.e., LcHSP70-1, LcHSP70-5, LcHSP70-10, LcHSP70-14, LcHSP70-16, and LcHSP70-18), their relative expression levels were assessed under different abiotic stresses using qRT-PCR. The results indicated that the gene family members exhibited diverse responses to low temperature, high temperature, drought, and salt stress, with significant variations in their expression levels across different time periods. These results provide a foundation for further exploration of the function of the LcHSP70 gene family.