Instituto Valenciano de Investigaciones Agrarias (IVIA), Apartado Oficial, 46113 Moncada, Valencia, Spain.
Mol Plant Pathol. 2013 Sep;14(7):663-77. doi: 10.1111/mpp.12037. Epub 2013 May 14.
Sharka disease, caused by Plum pox virus (PPV), is the most important viral disease affecting Prunus species. A major PPV resistance locus (PPVres) has been mapped to the upper part of apricot (Prunus armeniaca) linkage group 1. In this study, a physical map of the PPVres locus in the PPV-resistant cultivar 'Goldrich' was constructed. Bacterial artificial chromosome (BAC) clones belonging to the resistant haplotype contig were sequenced using 454/GS-FLX Titanium technology. Concurrently, the whole genome of seven apricot varieties (three PPV-resistant and four PPV-susceptible) and two PPV-susceptible apricot relatives (P. sibirica var. davidiana and P. mume) were obtained using the Illumina-HiSeq2000 platform. Single nucleotide polymorphisms (SNPs) within the mapped interval, recorded from alignments against the peach genome, allowed us to narrow down the PPVres locus to a region of ∼196 kb. Searches for polymorphisms linked in coupling with the resistance led to the identification of 68 variants within 23 predicted transcripts according to peach genome annotation. Candidate resistance genes were ranked combining data from variant calling and predicted functions inferred from sequence homology. Together, the results suggest that members of a cluster of meprin and TRAF-C homology domain (MATHd)-containing proteins are the most likely candidate genes for PPV resistance in apricot. Interestingly, MATHd proteins are hypothesized to control long-distance movement (LDM) of potyviruses in Arabidopsis, and restriction for LDM is also a major component of PPV resistance in apricot. Although the PPV resistance gene(s) remains to be unambiguously identified, these results pave the way to the determination of the underlying mechanism and to the development of more accurate breeding strategies.
李痘病由李痘病毒（PPV）引起，是危害李属植物的最重要的病毒性病害。一个主要的 PPV 抗性位点（PPVres）已被定位在杏（Prunus armeniaca）连锁群 1 的上部。本研究构建了抗性品种‘Goldrich’中 PPVres 位点的物理图谱。使用 454/GS-FLX Titanium 技术对属于抗性单倍型 Contig 的细菌人工染色体（BAC）克隆进行测序。同时，利用 Illumina-HiSeq2000 平台获得了 7 个杏品种（3 个抗 PPV、4 个感 PPV）和 2 个感 PPV 的杏近缘种（P. sibirica var. davidiana 和 P. mume）的全基因组序列。在与桃基因组比对的记录中，在映射区间内发现的单核苷酸多态性（SNP）使我们能够将 PPVres 位点缩小到约 196 kb 的区域。与抗性连锁的多态性搜索导致根据桃基因组注释在 23 个预测转录本中鉴定出 68 个变体。根据变异调用和序列同源性推断的预测功能，对候选抗性基因进行排名。综合结果表明，类糜蛋白酶和 TRAF-C 同源结构域（MATHd）蛋白簇的成员是杏中抗 PPV 的最可能候选基因。有趣的是，MATHd 蛋白被假设控制着拟南芥中 potyvirus 的长距离运动（LDM），而 LDM 的限制也是杏中抗 PPV 的主要组成部分。尽管 PPV 抗性基因（s）仍未明确鉴定，但这些结果为确定其潜在机制和开发更准确的育种策略铺平了道路。
