Multiple translocation of the AVR-Pita effector gene among chromosomes of the rice blast fungus Magnaporthe oryzae and related species.
Multiple translocation of the AVR-Pita effector gene among chromosomes of the rice blast fungus Magnaporthe oryzae and related species.
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DOI：
10.1371/journal.ppat.1002147
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发表时间：
2011-07
期刊：
影响因子：
6.7
通讯作者：
Tosa Y
中科院分区：
文献类型：
--
作者：
Chuma I;Isobe C;Hotta Y;Ibaragi K;Futamata N;Kusaba M;Yoshida K;Terauchi R;Fujita Y;Nakayashiki H;Valent B;Tosa Y
稻瘟病菌是水稻稻瘟病的病原体，是一个世界性的毁灭性问题。这种真菌破坏了新开发的商业品种所赋予的抗性。为了解决稻瘟病菌如何如此迅速地适应新的抗性基因，我们检测了AVR-Pita的染色体定位，AVR-Pita是一个亚端粒基因家族，对应于Pita抗性基因，在不同的稻瘟病菌菌株中。病原菌（包括小麦和谷子病原菌）及其相关物种。我们发现AVR-Pita（AVR-Pita 1和AVR-Pita 2）在其基因组位置上高度可变，发生在第1、3、4、5、6、7号染色体和额外染色体上，特别是在水稻感染菌株中。当用M.除此之外，大多数AVR-Pita同源物都能引起Pita介导的抗性，即使是来自非水稻菌株的同源物也能引起Pita介导的抗性。AVR-Pita的侧翼是一个逆转录转座子，这可能有助于其在基因组中的多次易位。另一方面，缺乏无毒活性的家族成员AVR-Pita 3在绝大多数分离株中稳定地位于7号染色体上。这些结果表明，AVR-Pita在水稻分离物中的基因组位置的多样性是Pita在水稻中识别的结果。我们提出了一个模型，AVR-Pita的多重易位可能与其频繁的损失和恢复介导的个体之间的转移在无性群体。该模型表明AVR-Pita的高迁移率是其快速适应Pita的关键机制。一些真菌植物病原体的动态适应可以通过使用群体作为适应单位的无毒基因的缺失和恢复来实现。由稻瘟病菌引起的稻瘟病是全球水稻生产的严重威胁。几十种抗性基因可用于疾病控制，但真菌在田间2或3年内迅速进化以克服抗性基因。抗性需要识别相应的病原体“无毒效应物”，即宿主植物中真菌分泌的蛋白质或小分子。抗性基因的破坏涉及无毒效应子的突变，使其不再被抗性基因产物识别。我们描述了进化过程与亚端粒无毒效应AVR-Pita对应的水稻抗性基因Pita。比较感染水稻的无性真菌群体中的个体，AVR-Pita经常易位到不同的染色体上，包括不稳定的额外染色体。AVR-Pita发生在不同的染色体定位在人群中的杂草和谷子作物缺乏Pita，但这个位置是稳定的，在每个人口的个人。家族成员AVR-Pita 3缺乏相应的水稻抗性基因，在病原体的所有宿主适应群体中在单个染色体上显示出非常稳定的定位。AVR-Pita的易位可能与该基因在无性病原体群体中个体之间的频繁转移有关，该群体响应于Pita的零星部署的选择。
Magnaporthe oryzae is the causal agent of rice blast disease, a devastating problem worldwide. This fungus has caused breakdown of resistance conferred by newly developed commercial cultivars. To address how the rice blast fungus adapts itself to new resistance genes so quickly, we examined chromosomal locations of AVR-Pita, a subtelomeric gene family corresponding to the Pita resistance gene, in various isolates of M. oryzae (including wheat and millet pathogens) and its related species. We found that AVR-Pita (AVR-Pita1 and AVR-Pita2) is highly variable in its genome location, occurring in chromosomes 1, 3, 4, 5, 6, 7, and supernumerary chromosomes, particularly in rice-infecting isolates. When expressed in M. oryzae, most of the AVR-Pita homologs could elicit Pita-mediated resistance, even those from non-rice isolates. AVR-Pita was flanked by a retrotransposon, which presumably contributed to its multiple translocation across the genome. On the other hand, family member AVR-Pita3, which lacks avirulence activity, was stably located on chromosome 7 in a vast majority of isolates. These results suggest that the diversification in genome location of AVR-Pita in the rice isolates is a consequence of recognition by Pita in rice. We propose a model that the multiple translocation of AVR-Pita may be associated with its frequent loss and recovery mediated by its transfer among individuals in asexual populations. This model implies that the high mobility of AVR-Pita is a key mechanism accounting for the rapid adaptation toward Pita. Dynamic adaptation of some fungal plant pathogens may be achieved by deletion and recovery of avirulence genes using a population as a unit of adaptation. Rice blast disease, caused by Magnaporthe oryzae, is a serious threat to global rice production. Dozens of resistance genes are available for disease control, but the fungus rapidly evolves to overcome a resistance gene within 2 or 3 years in the field. Resistance requires recognition of corresponding pathogen “avirulence effectors”, proteins or small molecules secreted by the fungus in the host plant. Resistance gene breakdown involves mutation of the avirulence effector so that it is no longer recognized by the resistance gene product. We describe evolutionary processes associated with the subtelomeric avirulence effector AVR-Pita corresponding to rice resistance gene Pita. Comparing individuals in the asexual fungal population infecting rice, AVR-Pita has frequently been translocated to different chromosomes, including unstable supernumerary chromosomes. AVR-Pita occurs at different chromosomal localizations in populations from weeds and millet crops lacking Pita, but this location is stable in individuals of each population. Family member AVR-Pita3, which lacks a corresponding rice resistance gene, shows extremely stable localization on a single chromosome throughout all host-adapted populations of the pathogen. Translocation of AVR-Pita might be associated with the frequent transfer of this gene between individuals in the asexual pathogen population responding to selection by sporadic deployment of Pita.
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影响因子：
3.2
作者：
Chuma, Izumi;Zhan, Su-Wen;Tosa, Yukio
通讯作者：
Tosa, Yukio
影响因子：
64.8
作者：
Freitas-Junior, LH;Bottius, E;Scherf, A
通讯作者：
Scherf, A
影响因子：
4.5
作者：
Coleman JJ;Rounsley SD;Rodriguez-Carres M;Kuo A;Wasmann CC;Grimwood J;Schmutz J;Taga M;White GJ;Zhou S;Schwartz DC;Freitag M;Ma LJ;Danchin EG;Henrissat B;Coutinho PM;Nelson DR;Straney D;Napoli CA;Barker BM;Gribskov M;Rep M;Kroken S;Molnár I;Rensing C;Kennell JC;Zamora J;Farman ML;Selker EU;Salamov A;Shapiro H;Pangilinan J;Lindquist E;Lamers C;Grigoriev IV;Geiser DM;Covert SF;Temporini E;Vanetten HD
通讯作者：
Vanetten HD
影响因子：
2.8
作者：
Couch, BC;Kohn, LM
通讯作者：
Kohn, LM
影响因子：
5.1
作者：
Gout, Lilian;Kuhn, Marie Line;Rouxel, Thierry
通讯作者：
Rouxel, Thierry