Silencing a candidate nematode effector gene corresponding to the tomato resistance gene Mi-1 leads to acquisition of virulence
Silencing a candidate nematode effector gene corresponding to the tomato resistance gene Mi-1 leads to acquisition of virulence
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DOI：
10.1094/mpmi-21-5-0576
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发表时间：
2008-05-01
影响因子：
3.5
通讯作者：
Williamson, Valerie M.
中科院分区：
文献类型：
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作者：
Gleason, Cynthia A.;Liu, Qingli L.;Williamson, Valerie M.
番茄中的 Mi-1 基因可有效抵抗多种根结线虫，包括爪哇根结线虫。经过温室选择后，从无毒菌株的培养物中获得了可以用 Mi-1 在番茄上繁殖的爪哇小孢子菌株。 DNA印迹和扩增片段长度多态性(AFLP)分析表明这两种线虫菌株密切相关。 cDNA AFLP 的表达模式几乎相同，但 cDNA 片段 Cg-1 存在于无毒株中，但不存在于强毒株中。 DNA印迹显示，Cg-1对应于一个小基因家族的成员，与无毒株相比，强毒株中缺失一个或多个拷贝。除了转录本 3' 端附近存在组蛋白茎环外，Cg-1 与 GenBank 中的其他序列没有相似性。最长的开放阅读框为 32 个氨基酸，起始于预测转录本中的第四个 AUG。当 Mi-1 无毒菌株的线虫幼体浸泡在与预测的 Cg-1 转录物部分相对应的 dsRNA 中时，它们产生了对携带 Mi-1 基因的番茄有毒的后代，强烈表明 Cg-1 是线虫中 Mi-1 介导的抗性所必需的。
The Mi-1 gene in tomato confers effective resistance against several species of root-knot nematode, including Meloidogyne javanica. A strain of M. javanica that can reproduce on tomato with Mi-1 was obtained from a culture of an avirulent strain after greenhouse selection. DNA blots and amplified fragment length polymorphism (AFLP) analysis indicated that the two nematode strains are closely related. Expression patterns visualized as cDNA AFLPs were nearly identical except for a cDNA fragment, Cg-1, that was present in the avirulent strain but not in the virulent strain. DNA blots showed that Cg-1 corresponds to a member of a small gene family with one or more copies missing in the virulent strain compared with the avirulent strain. Except for the presence of a histone stem loop near the 3' end of the transcript, Cg-1 shows no similarity to other sequences in GenBank. The longest open reading frame is 32 amino acids and initiates at the fourth AUG in the predicted transcript. When nematode juveniles of the Mi-1-avirullent strain were soaked in dsRNA corresponding to part of the predicted Cg-1 transcript, they produced progeny that were virulent on tomato carrying the Mi-1 gene, strongly suggesting that Cg-1 is required in the nematode for Mi-1-mediated resistance.