Phytoplasmas are plant pathogenic bacteria transmitted by insects. As endosymbiotic bacteria that lack a cell wall, their membrane proteins are in direct contact with host cytoplasm. In phytoplasmas the immunodominant membrane proteins (IDPs), are the most abundant proteins of the cell membrane. The antigenic membrane protein (Amp), one of the three types of IDPs, is characterized by a positive selection pressure acting in their extracellular domain. In South America, the 'Candidatus Phytoplasma meliae' has been associated to chinaberry yellows disease. In the present work, we describe for the first time the structure, phylogeny and selection pressure of amp gene in sixteen 'Candidatus Phytoplasma meliae' isolates. Our results indicate that amp gene sequences preserve the structure, large extracellular domain flanked by to hydrophobic domains in the N- (signal peptide) and C-termini (transmembrane), previously described in its orthologues and high divergence in the amino acids residues from extracellular domain. Moreover, a positive selection pressure was detected predominantly in this region confirming previous reports.

中文翻译：

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'Candidatus Phytoplasma meliae'中amp基因序列的多样性分析

植原体是由昆虫传播的植物致病细菌。作为缺乏细胞壁的内共生细菌，它们的膜蛋白与宿主细胞质直接接触。在植物质体中，免疫优势膜蛋白（IDP）是细胞膜中最丰富的蛋白。抗原膜蛋白（Amp）是IDP的三种类型之一，其特征是在其细胞外结构域中发挥正选择压力。在南美，“ Candidatus Phytoplasma meliae”与china子黄病有关。在本工作中，我们首次描述了十六个念珠菌中amp基因的结构，系统发育和选择压力。疫霉菌。我们的结果表明，amp基因序列保留了结构，大的细胞外结构域，其侧翼是N-（信号肽）和C-termini（跨膜）中的疏水域，先前在其直系同源物中已有描述，并且细胞外氨基酸残基高度分散域。此外，主要在该区域检测到正选择压力，证实了先前的报道。