Bacterial soft rot (BSR) caused by subsp. () is a serious bacterial disease which negatively impact yield and quality in cucumber. However, the genetic mechanism of BSR resistance in cucumber has not been reported. Here, we investigated the BSR resistance of 119 cucumber core germplasm worldwide at the seedling stage and identified 26 accessions highly resistant to BSR. A total of 1 642 740 single-nucleotide polymorphisms (SNPs) were used to conduct GWAS, and five loci associated with BSR resistance were detected on four chromosomes: , , , and . Based on haplotype analysis, sequence polymorphisms, functional annotation and qRT-PCR analysis, six candidate genes were identified within the five loci. , , , , , and each had nonsynonymous SNPs, and were significantly up-regulated in the resistant genotypes after inoculation. And in the susceptible genotype was significantly up-regulated after inoculation. The identification of these candidate genes lays a foundation for understanding the genetic mechanism of BSR resistance in cucumber. Generally, our study mined genes associated with BSR resistance in cucumber seedlings and will assist the breeding of BSR-resistant cucumber cultivars.

中文翻译：

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全基因组关联研究确定了黄瓜幼苗细菌性软腐病抗性的候选基因


由亚种引起的细菌性软腐病（BSR）。 ()是一种严重的细菌性疾病，对黄瓜产量和品质产生负面影响。然而，黄瓜抗BSR的遗传机制尚未见报道。本研究对全球119份黄瓜核心种质苗期BSR抗性进行了调查，鉴定出26份对BSR高度抗性的材料。总共使用 1 642 740 个单核苷酸多态性 (SNP) 进行 GWAS，在 4 条染色体上检测到 5 个与 BSR 抗性相关的位点： 、 、 和 。基于单倍型分析、序列多态性、功能注释和qRT-PCR分析，在5个位点内鉴定出6个候选基因。 、 、 、 、 、 和 均具有非同义SNP，并且在接种后抗性基因型中显着上调。并且在易感基因型接种后显着上调。这些候选基因的鉴定为了解黄瓜BSR抗性遗传机制奠定了基础。一般来说，我们的研究挖掘了黄瓜幼苗中与 BSR 抗性相关的基因，将有助于抗 BSR 黄瓜品种的选育。