Sullenberger Matthew T, Foolad Majid R
Department of Plant Science and the Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University, Park, PA, United States.
Front Plant Sci. 2024 Nov 15;15:1482241. doi: 10.3389/fpls.2024.1482241. eCollection 2024.
Late blight (LB), caused by the oomycete , is one of the most devastating diseases of the cultivated tomato () worldwide. Attempts to control the disease through fungicide applications are becoming less effective, as new and aggressive genotypes of the pathogen emerge. Further, some new genotypes overcome the currently available resistance in tomato, necessitating the identification, characterization, and utilization of new sources of host resistance. In the present study, to detect QTLs underlying LB resistance in a recently-identified LB-resistant accession (PI 270442), an F population (n = 1,175) of a cross between PI 270442 and LB-susceptible tomato breeding line Fla. 8059 was screened for LB resistance and subjected to selective genotyping. A total of 19,839 single-nucleotide polymorphisms (SNPs) were identified from reduced representation libraries (RRLs) constructed from the parents, of which 212 were used to build a genetic linkage map and locate QTLs. Ten LB-resistance QTLs were identified in PI 270442 on chromosomes 1, 2, 5, 6, 10, 11 and 12, of which those on chromosomes 6, 10 and 11 were the strongest and co-localized with previously-reported LB-resistance QTLs. Genomic locations of the QTLs were compared with the tomato physical map, which resulted in the identification of several candidate genes that might be underpinning the LB resistance in PI 270442. The identified QTL-linked markers can be used in breeding programs to transfer resistance from PI 270442 into the cultivated tomato via marker-assisted breeding and to develop near-isogenic lines for fine mapping of the QTLs.
晚疫病（LB）由卵菌引起，是全球栽培番茄最具毁灭性的病害之一。随着病原菌新的侵袭性基因型出现，通过施用杀菌剂来控制该病的效果越来越差。此外，一些新基因型克服了番茄目前的抗性，因此有必要鉴定、表征和利用新的寄主抗性来源。在本研究中，为了检测最近鉴定出的晚疫病抗性材料（PI 270442）中晚疫病抗性的潜在数量性状位点（QTL），对PI 270442和晚疫病感病番茄育种系Fla. 8059杂交产生的F群体（n = 1175）进行了晚疫病抗性筛选并进行了选择性基因分型。从亲本构建的简化代表性文库（RRL）中鉴定出总共19839个单核苷酸多态性（SNP），其中212个用于构建遗传连锁图谱并定位QTL。在PI 270442的第1、2、5、6、10、11和12号染色体上鉴定出10个晚疫病抗性QTL，其中第6、10和11号染色体上的QTL最强，且与先前报道的晚疫病抗性QTL共定位。将这些QTL的基因组位置与番茄物理图谱进行比较，从而鉴定出几个可能是PI 270442晚疫病抗性基础的候选基因。所鉴定的与QTL连锁的标记可用于育种计划，通过标记辅助育种将抗性从PI 270442转移到栽培番茄中，并开发近等基因系用于QTL的精细定位。
