西瓜抗炭疽病的遗传分析和抗性基因定位研究

Genetic Analysis and Molecular Mapping of Watermelon Anthrucnose Resistance Gene Rco-1

西瓜炭疽病(Anthracnose)是由瓜类炭疽病菌(Colletotrichumorbiculare)引起的真菌性病害。本研究以抗病自交系PI189225和感病自交系Black Diamond杂交并自交获得F1、F2、F3为材料,采用炭疽病菌生理小种1接种,对西瓜抗炭疽病生理小种1进行遗传规律分析和基因定位研究。研究结果表明,西瓜炭疽病抗性基因由显性单基因控制,抗病对感病为显性,将此基因命名为Rco-1。用分离群体分组分析法(BSA)和AFLP分子标记技术对PI189225中的抗炭疽病基因进行分子标记鉴定,并利用MAPMAKER/Exp version 3.0软件进行了标记与目的基因间的遗传距离计算,发现E4/M19、E1/M8、E29/M5与抗炭疽病基因Rco-1连锁,遗传距离分别为34.8、23.4、6.9cM。为采用分子标记辅助选育抗炭疽病西瓜新品种奠定了基础。

Anthracnose, caused by Colletotrichum orbiculare, is an important disease of watermelon worldwide. Thus far, genes related to the resistance to this disease remain largely unknown. In the current study, the heredity and molecular genetic mapping of the resistance to Colletotrichum orbiculare race 1 were explored. The F1 , F2 populations and an F3 family derived from the cross between the watermelon cultivar PI189225 （resistant） and Black Diamond （susceptible） were inoculated with the CoUetotrichum orbiculare race I. Results showed that a single dominant gene conferred Anthracnose resistance in PI189225, which was temporarily designated as Rco - 1. DNA markers linked to Rco - 1 were identified by bulked segregant analysis （BSA） using the amplified fragment length polymorphism （AFLP） technique. Three AFLP markers （E4/M19, El/M8 and E29/MS） were identified as linked to Rco - 1 with the genetic distance being 34.8cM, 23.4cM and 6.9cM, respectively. These marker are useful to tag the Rco - 1 locus and thus will facilitate marker-assisted selection for resistance to anthracnose.