立枯丝核菌不同融合群菌株GPD基因的克隆及序列特征分析

Characterization of Glyceraldehyde-3-phosphate Dehydrogenase Gene Sequences of Different Anastomosis Group Rhizoctonia solani

利用同源克隆的方法对11个立枯丝核菌标准融合群菌株的GPD基因进行了分离。分析发现不同融合群立枯丝核菌GPD基因在外显子数目、编码蛋白长度及内含子剪切方式等方面存在差异,如AG-2-2ⅢB、AG-2-2Ⅳ、AG-8三个融合群的GPD基因的外显子个数为10个,其他融合群均为11个;AG-8融合群的GPD基因的编码蛋白长度为267个氨基酸,其余融合群的GPD基因的编码蛋白长度约为340个氨基酸。AG-2-2ⅢB、AG-2-2Ⅳ、AG-8三个融合群的GPD基因在98、98、272氨基酸位点的内含子发生了缺失。基于蛋白序列的进化分析表明不同融合群之间GPD基因编码蛋白存在明显差异,可以有效地将不同融合群菌株区分开来;同时,不同物种之间GPD基因在进化上仍具有一定保守性,立枯丝核菌自身的GPD基因蛋白序列归为一类且与担子菌门同源性最高。这些结果表明进行保守基因序列差异分析是进行立枯丝核菌分类分群研究的新思路。

Full length cDNA sequences of glyceraldehyde-3-phosphate dehydrogenase （GPD） gene from 11 anastomosis groups （AGs） of Rhizoctonia solani were isolated by PCR-based strategies. The open reading frames （ORFs） of the GPD genes（from ATG to TGA） showed some differences in exon numbers, splicing modes and lengths of coding sequences. GPD genes from AG-2-2Ⅲ B, AG-2-2 IV and AG-8 have 10 exons, while those from the other AGs have 11 exons; GPD gene from AG-8 encodes a protein of 267 amino acids, those from the other AGs encode proteins with about 340 amino acids. Meanwhile, intron deletions were found in the GPD genes from AG-2-2 Ⅲ B, AG-2-2 IV and AG-8 at amino acid 98, 98 and 272, respectively. Phylogenetic analysis show that the GPD genes can effectively distinguish the different AGs. Further, the GPD genes from different AOs can differentiate all the AGs of R. solani from other fungi, implying the GPD gene is a useful alternative to the 5.8S rDNA-ITS gene for determination of phylogenetic relationships among different AGs and between Rhizoctonia and other fungi.