The complex hybrid origins of the root knot nematodes revealed through comparative genomics.
The complex hybrid origins of the root knot nematodes revealed through comparative genomics.
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作者：
Lunt DH;Kumar S;Koutsovoulos G;Blaxter ML
根结线虫（Root knot nematodes， RKN）可以感染世界上大多数农作物物种，是所有植物病原体中最重要的一种。然而，到目前为止，我们对它们的起源或它们极端多食的基因组基础知之甚少。最具破坏性的病原体通过强制性有丝分裂孤雌生殖繁殖，有人认为这些物种起源于未知亲本分类群之间的种间杂交。我们对二倍体减数分裂孤雌原Meloidogyne floridensis的基因组进行了测序，并使用比较基因组学方法来验证该物种参与热带有丝分裂孤雌原Meloidogyne incognita杂交起源的假设。利用系统基因组学分析方法，对密花蓟马、不认识密花蓟马和一个外群种密花蓟马的基因家族进行了基因组进化史的追溯，结果表明密花蓟马是不认识蓟马杂交起源中的亲本种之一。对floridensis基因组本身的分析显示，在不同的拷贝中存在许多基因位点，就像在M. incognita中一样，表明它也有一个杂交起源。三倍体的incognita被证明是floridensis和第三个未被识别的亲本之间复杂的双重杂交。农业上重要的RKN有非常复杂的起源，包括通过杂交将几个亲本基因组混合在一起，它们的极端多食性和在农业环境中的成功可能与这种杂交有关，产生了自然选择可以起作用的越界变异。现在很清楚，由于物种的起源复杂，通过单个标记位点研究RKN变异可能会失败，而多物种群体基因组学对于理解这一重要物种复合体的杂交多样性和适应性变异至关重要。这种比较基因组分析提供了一个令人信服的例子，说明杂交在产生更普遍的动物物种多样性方面的重要性和复杂性。
Root knot nematodes (RKN) can infect most of the world’s agricultural crop species and are among the most important of all plant pathogens. As yet however we have little understanding of their origins or the genomic basis of their extreme polyphagy. The most damaging pathogens reproduce by obligatory mitotic parthenogenesis and it has been suggested that these species originated from interspecific hybridizations between unknown parental taxa. We have sequenced the genome of the diploid meiotic parthenogen Meloidogyne floridensis, and use a comparative genomic approach to test the hypothesis that this species was involved in the hybrid origin of the tropical mitotic parthenogen Meloidogyne incognita. Phylogenomic analysis of gene families from M. floridensis, M. incognita and an outgroup species Meloidogyne hapla was carried out to trace the evolutionary history of these species’ genomes, and we demonstrate that M. floridensis was one of the parental species in the hybrid origins of M. incognita. Analysis of the M. floridensis genome itself revealed many gene loci present in divergent copies, as they are in M. incognita, indicating that it too had a hybrid origin. The triploid M. incognita is shown to be a complex double-hybrid between M. floridensis and a third, unidentified, parent. The agriculturally important RKN have very complex origins involving the mixing of several parental genomes by hybridization and their extreme polyphagy and success in agricultural environments may be related to this hybridization, producing transgressive variation on which natural selection can act. It is now clear that studying RKN variation via individual marker loci may fail due to the species’ convoluted origins, and multi-species population genomics is essential to understand the hybrid diversity and adaptive variation of this important species complex. This comparative genomic analysis provides a compelling example of the importance and complexity of hybridization in generating animal species diversity more generally.
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影响因子：
64.8
作者：
Dasmahapatra, Kanchon K.;Walters, James R.;Briscoe, Adriana D.;Davey, John W.;Whibley, Annabel;Nadeau, Nicola J.;Zimin, Aleksey V.;Hughes, Daniel S. T.;Ferguson, Laura C.;Martin, Simon H.;Salazar, Camilo;Lewis, James J.;Adler, Sebastian;Ahn, Seung-Joon;Baker, Dean A.;Baxter, Simon W.;Chamberlain, Nicola L.;Chauhan, Ritika;Counterman, Brian A.;Dalmay, Tamas;Gilbert, Lawrence E.;Gordon, Karl;Heckel, David G.;Hines, Heather M.;Hoff, Katharina J.;Holland, Peter W. H.;Jacquin-Joly, Emmanuelle;Jiggins, Francis M.;Jones, Robert T.;Kapan, Durrell D.;Kersey, Paul;Lamas, Gerardo;Lawson, Daniel;Mapleson, Daniel;Maroja, Luana S.;Martin, Arnaud;Moxon, Simon;Palmer, William J.;Papa, Riccardo;Papanicolaou, Alexie;Pauchet, Yannick;Ray, David A.;Rosser, Neil;Salzberg, Steven L.;Supple, Megan A.;Surridge, Alison;Tenger-Trolander, Ayse;Vogel, Heiko;Wilkinson, Paul A.;Wilson, Derek;Yorke, James A.;Yuan, Furong;Balmuth, Alexi L.;Eland, Cathlene;Gharbi, Karim;Thomson, Marian;Gibbs, Richard A.;Han, Yi;Jayaseelan, Joy C.;Kovar, Christie;Mathew, Tittu;Muzny, Donna M.;Ongeri, Fiona;Pu, Ling-Ling;Qu, Jiaxin;Thornton, Rebecca L.;Worley, Kim C.;Wu, Yuan-Qing;Linares, Mauricio;Blaxter, Mark L.;Ffrench-Constant, Richard H.;Joron, Mathieu;Kronforst, Marcus R.;Mullen, Sean P.;Reed, Robert D.;Scherer, Steven E.;Richards, Stephen;Mallet, James;McMillan, W. Owen;Jiggins, Chris D.
通讯作者：
Jiggins, Chris D.
影响因子：
11.8
作者：
Bisharat N;Cohen DI;Harding RM;Falush D;Crook DW;Peto T;Maiden MC
通讯作者：
Maiden MC
影响因子：
14.9
作者：
Benson DA;Cavanaugh M;Clark K;Karsch-Mizrachi I;Lipman DJ;Ostell J;Sayers EW
通讯作者：
Sayers EW
影响因子：
4.9
作者：
Czypionka, Till;Cheng, Jie;Nolte, Arne W.
通讯作者：
Nolte, Arne W.
DOI：
10.1079/9781845934927.0182
发表时间：
2010-01-01
期刊：
ROOT-KNOT NEMATODES
影响因子：
--
作者：
Chitwood, David J.;Perry, Roland N.
通讯作者：
Perry, Roland N.