Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, ITBB, CATAS, Xueyuan Rd No 4, Haikou City, Hainan Province, People's Republic of China, 571101.
BMC Genet. 2018 Jul 13;19(1):45. doi: 10.1186/s12863-018-0627-6.
Glutathione S-transferases (GSTs) have been reported to regulate the plant tolerance to environmental stresses. Many plant GSTs exhibited the roles on promoting tolerance to drought stress, oxidative stress and plant hormones. The biological function of GSTs has been well characterized in Arabidopsis thaliana in response to exogenous environmental stresses. However, their regulation function under exogenous environmental stresses regulating leaf abscission in cassava (Manihot esculenta Crantz) remained unknown.
Here, 83 GSTs were identified from tropical plant cassava. The amino acid motifs and phylogenetic analyses indicated that MeGSTs were divided into 9 classes. The global expression analyses were carried out to analyze the gene expression patterns of MeGST in cassava abscission zones by comparing the MeGST genes expression patterns in both ethylene and drought induced cassava leaf abscission. Totally, 34 GSTs were detected to express in both ethylene and drought induced leaf abscission in cassava abscission zones. Comparison of GST expression profiling between ethylene and drought induced leaf abscission suggested that Tau GST genes showed with the similar expression in both treatments induced leaf abscission in cassava abscission zone. GO annotation indicated that all 17 Tau GST genes participated in the pathway of toxin catabolism (GO: 0009407). The expression levels of 17 Tau MeGST genes were analyzed in two cassava cultivars, 'SC124' and 'Arg7', the two cultivars exhibit different levels of leaf abscission when suffered from the same environmental stress. Higher expression levels of Tau MeGSTs were detected in the precocious abscission Arg7 cultivar, while lower expression levels in delayed abscission SC124 cultivar. All the results indicated that Tau MeGSTs have the function in regulation the cassava leaf abscission under environmental stresses.
Analysis of the expression patterns of GSTs in various abscission-promoting treatments in cassava abscission zones helps us to understand the possible roles of GSTs in cassava leaf abscission.
谷胱甘肽 S-转移酶（GSTs）已被报道可调节植物对环境胁迫的耐受性。许多植物 GSTs 表现出促进对干旱胁迫、氧化应激和植物激素的耐受性的作用。GSTs 在拟南芥中对外源环境胁迫的反应中的生物学功能已经得到很好的描述。然而，它们在调节木薯（Manihot esculenta Crantz）外源环境胁迫下叶片脱落中的调控功能仍不清楚。
从热带植物木薯中鉴定出 83 种 GSTs。氨基酸基序和系统发育分析表明，MeGSTs 分为 9 类。通过比较乙烯和干旱诱导的木薯叶片脱落中 MeGST 基因的表达模式，对木薯脱落区 MeGST 的基因表达模式进行了全局表达分析。总共检测到 34 个 GST 在乙烯和干旱诱导的木薯脱落区表达。乙烯和干旱诱导的叶片脱落中 GST 表达谱的比较表明，Tau GST 基因在两种处理诱导的叶片脱落中表现出相似的表达。GO 注释表明，所有 17 个 Tau GST 基因都参与了毒素代谢途径（GO: 0009407）。在两个木薯品种“SC124”和“Arg7”中分析了 17 个 Tau MeGST 基因的表达水平，这两个品种在受到相同环境胁迫时表现出不同程度的叶片脱落。在早熟脱落的 Arg7 品种中检测到 Tau MeGST 基因的较高表达水平，而在延迟脱落的 SC124 品种中则较低。所有结果表明，Tau MeGSTs 在环境胁迫下调节木薯叶片脱落中具有功能。
分析木薯脱落区各种促进脱落处理中 GSTs 的表达模式有助于我们理解 GSTs 在木薯叶片脱落中的可能作用。
