文心兰WRKY转录因子在印度梨形孢诱导的抗软腐病作用中的响应分析

Response analysis of WRKY transcription factors in resistance to soft rot induced by Piriformospora indica in Oncidium

从文心兰侵染软腐病转录组库中鉴定出72条WRKY蛋白序列,长度分布110~719个氨基酸,平均长度319.8个氨基酸。72条文心兰WRKY蛋白序列中14条被分到Ⅰ组、42条序列被分到Ⅱ组、16条序列被分到Ⅲ组,其中Ⅱ组还可以进一步分为7个亚组;72条序列均至少含有1个WRKY结构域和C2H2型锌指基序,来自I组的序列含有2个WRKY结构域。通过对筛选的12条文心兰WRKY基因进行荧光定量分析,发现其表达基本验证高通量表达模式,并可分成三种,来自第一种与第三种的OncWRKY44 (Ⅰ)、OncWRKY69 (Ⅱg)与OncWRKY70 (Ⅱg) 3个WRKY基因可以被外源水杨酸与茉莉酸甲酯诱导,并在共生植株的侵染位点中呈现最高表达量,它们可能是参与印度梨形孢诱导的系统抗性的重要节点基因。

In this paper, based on transcriptome library of Oncidium after soft rot infection, 72 WRKY protein sequences were identified, with a length distribution of 110–719 amino acids, an average length of 319.8 amino acids. Among the 72 WRKY protein sequences, 14 sequences were classified into group Ⅰ, 42sequences were classified into group Ⅱ, and 16 sequences were classified into group Ⅲ. Group Ⅱ could be further divided into 7 subgroups. Those 72 protein sequences contain at least one WRKY domain and C2H2 type zinc finger motif, of which the sequences from group I contain two WRKY domains. 12 WRKY genes were screened for fluorescence quantitative PCR analysis, results showed that the expression pattern of those 12 WRKY genes basically verified the high-throughput expression pattern, and the responses pattern could be divided into three types. Among them, OncWRKY44(Ⅰ), OncWRKY69(Ⅱg) and OncWRKY70(Ⅱg) 3 WRKY genes from the first and third types could be induced by salicylic acid and methyl jasmonate,and showed the highest expression level in the infection site of symbiotic plants, which may be important node genes involved in the induced system resistance brought by Piriformospora indica.