Abstract: Glycosyltransferases play important roles in plants stress responses by glycosylating hormones and secondary metabolites. In order to unravel the effect of glycosyltransferase in potato resistance aginst Phytophthora infestans, a glycosyltransferase-like gene StKOB1 was cloned from potato cultivar ‘C88’, and its expression and function were analyzed. Using quantitative reverse transcriptase PCR, the expression pattern of StKOB1 in response to Phytophthora infestans, methyl jasmonic acid (MeJA), salicylic acid (SA), ethephon (ET) were analyzed. Transient expression of StKOB1 and virus-induced gene silencing (VIGS) of NbKOB1 were performed in N. benthamiana to investigate KOB1 function against P. infestans. The results indicated that StKOB1 protein contained one transmembrane domain (27~47 aa) and one glycosyltransferase function domain (115~381 aa). The expression of StKOB1 was induced by P. infestans and MeJA. Transient expression of StKOB1 didnt enhance disease resistance of N. benthamiana, while NbKOB1-silenced plants increased susceptibility to P. infestans. The results suggested that the StKOB1 was involved in potato defense to P. infestans.

Key words: potato, late blight, StKOB1, Nicotiana benthamiana, virus-induced gene silencing

摘要： 糖基转移酶通过参与多种物质糖基化修饰在植物抗逆胁迫方面发挥重要作用。为了解糖基转移酶基因在马铃薯晚疫病抗性中的作用，从马铃薯栽培种‘合作88’中克隆类糖基转移酶基因StKOB1，分析了该基因的表达特性及功能。通过实时定量PCR技术，分析StKOB1受晚疫病菌（Phytophthora infestans）、水杨酸、茉莉酸甲酯及乙烯利诱导表达模式，利用基因瞬时表达和病毒诱导的基因沉默（virus-induced gene silencing，VIGS）技术在本氏烟草中超量表达和沉默该基因，然后进行晚疫病抗性鉴定。结果表明，StKOB1蛋白结构域包含1个跨膜结构域（27~47 aa），1个糖基转移酶功能域（115~381 aa）。StKOB1基因受晚疫病菌和茉莉酸甲酯诱导表达。瞬时超量表达StKOB1基因未能增强植物抗病性，但与对照植株相比，NbKOB1沉默植株的抗病性显著降低。上述结果说明StKOB1参与晚疫病抗性调控。

关键词: 马铃薯, 晚疫病, StKOB1, 本氏烟草, 病毒诱导基因沉默