Rapid identification of the Leptosphaeria maculans avirulence gene AvrLm2 using an intraspecific comparative genomics approach
Rapid identification of the Leptosphaeria maculans avirulence gene AvrLm2 using an intraspecific comparative genomics approach
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DOI：
10.1111/mpp.12228
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发表时间：
2015-09-01
影响因子：
4.9
通讯作者：
Borhan, M. Hossein
中科院分区：
文献类型：
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作者：
Ghanbarnia, Kaveh;Fudal, Isabelle;Borhan, M. Hossein
甘蓝型油菜(Brassica Napus)黑斑病病原菌Leptosphaeria maculans的5个无毒基因已通过图位克隆获得。在本研究中，使用比较基因组学方法克隆了先前定位的AvrLm2。由于缺乏与AvrLm2表型一致的存在-缺失基因多态，对36株黄斑葡萄球菌进行了重新测序，并分析了MAP区间内预测的小分泌蛋白编码基因的单核苷酸多态(SNPs)。在LmCys1中发现了三个与AvrLm2表型一致的SNPs，以前被认为是一个假定的效应编码基因。用候选AvrLm2等位基因LmCys1与一个致病分离物互补，恢复了含Rlm2的甘蓝型油菜品系的致病表型。AvrLm2编码一种小的富含半胱氨酸的蛋白质，与公共数据库中的其他蛋白质相似性较低。与其他毒力基因不同，AvrLm2位于基因组富含AT等值线的一个小GC岛上，在强毒分离物中从未被发现完全删除。
Five avirulence genes from Leptosphaeria maculans, the causal agent of blackleg of canola (Brassica napus), have been identified previously through map-based cloning. In this study, a comparative genomic approach was used to clone the previously mapped AvrLm2. Given the lack of a presence-absence gene polymorphism coincident with the AvrLm2 phenotype, 36 L.maculans isolates were resequenced and analysed for single-nucleotide polymorphisms (SNPs) in predicted small secreted protein-encoding genes present within the map interval. Three SNPs coincident with the AvrLm2 phenotype were identified within LmCys1, previously identified as a putative effector-coding gene. Complementation of a virulent isolate with LmCys1, as the candidate AvrLm2 allele, restored the avirulent phenotype on Rlm2-containing B.napus lines. AvrLm2 encodes a small cysteine-rich protein with low similarity to other proteins in the public databases. Unlike other avirulence genes, AvrLm2 resides in a small GC island within an AT-rich isochore of the genome, and was never found to be deleted completely in virulent isolates.