The Rpi-blb2 gene from Solanum bulbocastanum is an Mi-1 gene homolog conferring broad-spectrum late blight resistance in potato
The Rpi-blb2 gene from Solanum bulbocastanum is an Mi-1 gene homolog conferring broad-spectrum late blight resistance in potato
复制标题
DOI：
10.1111/j.1365-313x.2005.02527.x
复制
发表时间：
2005-10-01
期刊：
影响因子：
7.2
通讯作者：
Allefs, S
中科院分区：
文献类型：
--
作者：
van der Vossen, EAG;Gros, J;Allefs, S
随着毒力更强的、作物专用的和抗农药的病原菌菌株的迅速出现，开发对卵霉菌病原菌具有持久抗性的马铃薯和番茄作物的必要性日益增加。在这里，我们描述了球顶茄衍生的Rpi-blb2基因的位置克隆，该基因即使存在于马铃薯背景中也具有广谱的晚疫病抗性。Rpi-blb2的焦点最初是在几个四倍体回交群体中定位的，这些回交群体来自高度抗性的复杂种间杂交种ABPT（涉及的四种茄属植物：S. acaule， S. bulbocastanum， S. phureja和S. tuberosum的缩写），与番茄的Mi-1基因在6号染色体上的同一区域，该区域具有对线虫、蚜虫和白蝇的抗性。由于四倍体材料的重组受到抑制，我们对一个二倍体种内castanum F1群体进行了精细定位。利用二倍体abpt衍生克隆和抗性葡萄球菌亲本克隆制备的细菌人工染色体文库，利用抗性相关标记筛选Rpi-blb2位点的物理图谱。对跨越Rpi-blb2位点的ABPT-和S. bulbocastanum-衍生BAC克隆的分子分析表明，它至少含有15个Mi-1基因同源物（migs）。其中，5个基因被确定为Rpi-blb2的候选者。互补分析表明，一个ABPT-基因和一个球皮葡萄来源的MiGH基因能够对番茄和葡萄的易感表型进行互补。对这两个基因的序列分析表明它们是相同的。Rpi-blb2蛋白与Mi-1蛋白有82%的序列同源性。与Mi-1位点相比，Rpi-blb2位点的显著扩增表明染色体内重组或不等交叉在Rpi-blb2位点的进化中发挥了重要作用。两个相关基因组中Rpi-blb2/Mi-1位点的进化动态对比可能反映了相互作用病原体的相反进化潜力。
The necessity to develop potato and tomato crops that possess durable resistance against the oomycete pathogen Phytophthora infestans is increasing as more virulent, crop-specialized and pesticide resistant strains of the pathogen are rapidly emerging. Here, we describe the positional cloning of the Solanum bulbocastanum-derived Rpi-blb2 gene, which even when present in a potato background confers broad-spectrum late blight resistance. The Rpi-blb2 focus was initially mapped in several tetraploid backcross populations, derived from highly resistant complex interspecific hybrids designated ABPT (an acronym of the four Solanum species involved: S. acaule, S. bulbocastanum, S. phureja and S. tuberosum), to the same region on chromosome 6 as the Mi-1 gene from tomato, which confers resistance to nematodes, aphids and white flies. Due to suppression of recombination in the tetraploid material, fine mapping was carried out in a diploid intraspecific S. bulbocastanum F1 population. Bacterial artificial chromosome (BAC) libraries, generated from a diploid ABPT-derived clone and from the resistant S. bulbocastanum parent clone, were screened with markers linked to resistance in order to generate a physical map of the Rpi-blb2 locus. Molecular analyses of both ABPT- and S. bulbocastanum-derived BAC clones spanning the Rpi-blb2 locus showed it to harbor at least 15 Mi-1 gene homologs (MiGHs). Of these, five were genetically determined to be candidates for Rpi-blb2. Complementation analyses showed that one ABPT- and one S. bulbocastanum-derived MiGH were able to complement the susceptible phenotype in both S. tuberosum and tomato. Sequence analyses of both genes showed them to be identical. The Rpi-blb2 protein shares 82% sequence identity to the Mi-1 protein. Significant expansion of the Rpi-blb2 locus compared to the Mi-1 locus indicates that intrachromosomal recombination or unequal crossing over has played an important role in the evolution of the Rpi-blb2 locus. The contrasting evolutionary dynamics of the Rpi-blb2/Mi-1 loci in the two related genomes may reflect the opposite evolutionary potentials of the interacting pathogens.