西瓜抗小西葫芦黄花叶病毒基因的连锁分子标记研究

 小西葫芦黄花叶病毒中国株系(Zucchini yellow mosaic virus Chinese strain,ZYMV-CH)是危害我国西瓜的主要病毒。本实验以抗病毒病西瓜野生种质P.I.595203与感病的普通西瓜自交系98R为亲本,采用单粒传方式得到109个E代株系,分别对亲本、F₁及109个F₃代株系群体进行了苗期抗ZYMV-CH接种鉴定,通过F₃代群体的抗感分离情况,推测得到F₂代各单株的基因型,采用集团分离分析法(bulked segregant analysis,BSA)在F₂代建立抗感基因池,以亲本、F₁和抗感基因池为模板,对640条RAPD引物进行PCR扩增筛选,其中引物AK13在亲本、F₁和抗感基因池之间扩增出一条多态性片段(644bp),在F₂代群体上验证该多态性条带与ZYMV-CH的抗性基因呈现连锁关系,遗传连锁距离为8cM,定名为AK13_-644,该连锁标记在ZYMV-CH抗性转育后代自交系上得到了验证。最终将此RAPD标记成功转化成SCAR标记SCAK13_-644,该标记可以作为西瓜抗病毒病辅助选择的分子标记。

Identification of the molecular markers linked to the resistance gene to Zucchini yellow mosaic virus Chinese strain in watermelon

Zucchini yellow mosaic virus Chinese strain (ZYMV-CH) is a major virus that causes severe losses in watermelon. The 109 lines of F3 derived from the single cross of the resistant wild germplasm P. I. 595203 and the susceptible inbred 98R were identified for their resistance to ZYMV-CH. The genotypes of 109 F2 individuals were assumed by the segregation of F3 population resistance. Using bulked segregant analysis (BSA), 640 RAPD primers were screened in resistant and susceptible parents,F1 and bulks. We found that a 644 bp fragment specifically amplified with RAPD primer AK13 which were present in P. I. 595203 and the resistant gene bulk but absent in 98R and the susceptible gene bulk. It was confirmed that the marker AK13-644 was linked to the gene resistant to ZYMV-CH in P. I. 595203 by screening 109 F2 individuals and the linkage distance was 8 cM. The RAPD marker AK13-644 was confirmed in the introgressed resistant inbreds, and was transformed into SCAR marker SCAK13-644 successfully. The result showed that this marker could be useful for marker-assisted selection in watermelon breeding for virus resistance.