番茄抗晚疫病基因Ph-3的分子标记开发及应用

Analysis of tomato late blight resistance marker based on the analogues of Ph-3 gene

番茄晚疫病由卵菌疫霉属的致病疫霉菌（Phytophthora infestans）侵染引起。病菌对番茄致病性强,侵染寄主后通过气流散发孢子,多次重复侵染植株,引起晚疫病爆发,对番茄生产造成严重危害[1]。利用抗晚疫病资源,培育番茄抗病品种是降低晚疫病危害的有效途径。

Tomato late blight is caused by Phytophthora infestans,which sends out the spore in airflow and infects plants repeatedly in the field.Under favourable conditions,P.infestans spreads rapidly and the susceptible host will be devastated in few days.Wild tomatoes with resistance genes such as Ph-1,Ph-2,Ph-3,Ph-4,Ph-5-1 and Ph-5-2,are useful germplasm resources to breed late blight-resistant tomatoes.To efficiently introduce the Ph-3 resistance gene,several DNA markers were developed,including RAPD,CAPS etc.Recently,the Ph-3 gene was cloned from CLN2037B,encoding a CC-NBS-LRR protein.In this article,we cloned the Ph-3 analogues from 4 tomato inbred lines （LQH-1,620-1,877-1,and QL-1） with sensitive response to late blight.The Ph-3 homology from LQH-1,620-1,and 877-1 were inserted by a 306 bp fragment,assumably leading to 3 stop codon mutations.The Ph-3 homologous gene from QL-1 encoding an 848 aa protein,was different from the Ph-3 resistance gene in both DNA and protein sequences.Utilizing the DNA differences between Ph-3/ph-3 analogues,we developed DNA markers to facilitate the screening of mass populations for potential resistant tomatoes to late blight.