巨桉糖基转移酶基因EgrGATL1序列特征及表达分析

EgrGATL1（Eucgr.I01882）是巨桉Eucalyptus grandis糖基转移酶GT8家族中GATL子类GATL-a子组的成员，多参与细胞壁组分如果胶、木聚糖等的生物合成。实时定量聚合酶链式反应（qRT-PCR）分析表明:EgrGATL1在木质部和韧皮部的相对表达量较高；不同低温（-8，-4，0，4，8℃）和4℃不同时间（0，2，6，12，24，48 h）处理对EgrGATL1都有强烈诱导作用。4℃不同时间处理下，EgrGATL1基因共表达产物主要参与代谢途径分析数据库（KEGG）中的糖代谢和氨基酸代谢途径。干旱胁迫对EgrGATL1有诱导作用；100 μmol·L-1茉莉酸甲酯（MeJA）处理对EgrGATL1表达呈现瞬时诱导效应；200 mmol·L-1氯化钠（NaCl）和100 μmol·L-1脱落酸（ABA）对其表达有抑制作用，而且随处理时间延长，2种处理对EgrGATL1的抑制规律有很强同步性。这些结果说明:EgrGATL1有可能通过参与细胞壁组分生物合成和ABA等植物生长调节剂活性调控，在巨桉低温、干旱和高盐等非生物逆境响应过程中发挥一定作用。

Glycosyltransferases gene EgrGATL1 in Eucalyptus grandis

In Eucalyptus grandis, EgrGATL1 (Eucgr. I01882), a member of the glycosyltransferases 8 family belongs to the GATL subfamily, which contributes to the biosynthesis of cell wall components such as pectin and xylan, is classified as the GATL-a subgroup. In this study, the protein sequence of EgrGATL1 was analyzed and cis-elements were searched in the promoter sequence of this gene with MathInspector software. Real time fluorescence quantitative Polymerase Chain Reaction(qRT-PCR) method was used to evaluate expression pattern of EgrGATL1 under treatments of low temperatures (-8, -4, 0, 4, 8℃), time course at 4℃ (0, 2, 6, 12, 24, 48 h), drought, 100 μmol·L-1 MeJA, 200 mmol·L-1 NaCl and 100 μmol·L-1 ABA. In addition, a KEGG analysis was used to test co-expression genes of EgrGATL1 under treatment of time course at 4℃. The protein sequence analysis showed EgrGATL1 contains a typical GT8 domain. Results of expression in different tissues showed that expression of EgrGATL1 was higher in xylem and phloem than in roots and leaves. Low temperature (-8, -4, 0, 4, 8℃) and time course treatment at 4℃ both can promote the expression of EgrGATL1. With KEGG analysis, 25 genes co-expressed with EgrGATL1 can match to KEGG pathways, 11 genes belong to the sugar metabolism pathways and 8 genes were distributed to amino acid metabolism pathways. EgrGATL1 was also induced by drought and showed transient induction with the 100 μmol·L-1 MeJA treatment. And, there is no significant difference between the expression patterns of EgrGATL1 with treatments of 200 mmol·L-1 NaCl and 100 μmol·L-1 ABA. Thus, EgrGATL1 was possibly involved in cell wall remodeling and with activity of hormones such as ABA, thereby implying a possible role in low temperature, drought, and salinity stress responses in E. grandis.