Positive selection in AvrP4 avirulence gene homologues across the genus Melampsora
Positive selection in AvrP4 avirulence gene homologues across the genus Melampsora
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DOI：
10.1098/rspb.2009.0328
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发表时间：
2009-08-22
影响因子：
4.7
通讯作者：
Burdon, Jeremy J.
中科院分区：
文献类型：
--
作者：
Van der Merwe, Marlien M.;Kinnear, Mark W.;Burdon, Jeremy J.
病原菌与寄主植物相互作用的基因在正达尔文选择或平衡选择的作用下进化。在这项研究中，一个单拷贝无毒基因，AvrP 4，在植物病原体亚麻栅锈菌，被用来调查这样的基因跨物种的进化。获得部分翻译延伸因子1-α序列以建立栅锈菌属物种之间的系统发育关系。我们扩增了AvrP 4同源物的物种致病的主机从不同的植物科和订单，在整个推断的基因组。AvrP 4序列的翻译揭示了预测的信号肽，并且朝向蛋白质的C-末端，在所有序列中鉴定出六个相同间隔的半胱氨酸。最大似然分析的同义与非同义的替代率表明，积极的选择发挥了作用，在该基因的进化过程中的属的多样化。在显著正选择下的14个密码子位于C-末端28个氨基酸区域，表明该区域在大多数测序的加入物中与宿主分子相互作用。对基因的选择压力可能是由于基因的致病性或无毒功能或两者兼而有之。
Pathogen genes involved in interactions with their plant hosts are expected to evolve under positive Darwinian selection or balancing selection. In this study a single copy avirulence gene, AvrP4, in the plant pathogen Melampsora lini, was used to investigate the evolution of such a gene across species. Partial translation elongation factor 1-alpha sequences were obtained to establish phylogenetic relationships among the Melampsora species. We amplified AvrP4 homologues from species pathogenic on hosts from different plant families and orders, across the inferred phylogeny. Translations of the AvrP4 sequences revealed a predicted signal peptide and towards the C-terminus of the protein, six identically spaced cysteines were identified in all sequences. Maximum likelihood analysis of synonymous versus nonsynonymous substitution rates indicated that positive selection played a role in the evolution of the gene during the diversification of the genus. Fourteen codons under significant positive selection reside in the C-terminal 28 amino acid region, suggesting that this region interacts with host molecules in most sequenced accessions. Selection pressures on the gene may be either due to the pathogenicity or avirulence function of the gene or both.