Alessio Florencia Ivette, Bongiorno Vanina Aylen, Marcone Carmine, Conci Luis Rogelio, Fernandez Franco Daniel
Instituto de Patología Vegetal (IPAVE), Centro de Investigaciones Agropecuarias (CIAP), Instituto Nacional de Tecnología Agropecuaria (INTA), Córdoba X5020ICA, Argentina.
Unidad de Fitopatología y Modelización Agrícola (UFYMA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba X5020ICA, Argentina.
Microorganisms. 2025 May 21;13(5):1170. doi: 10.3390/microorganisms13051170.
Phytoplasmas of the X-disease group (16SrIII) are economically significant pathogens in South America, causing severe crop losses. Traditional classification based on the 16S rRNA gene has limitations in resolving closely related strains, prompting the exploration of alternative markers. This study focuses on the immunodominant membrane proteins imp and idpA, which exhibit high variability and play crucial roles in host-pathogen interactions. Through molecular characterization of and genes in 16SrIII subgroups, we identified significant genetic diversity and distinct evolutionary pressures. The gene, under positive selection, showed high variability in its hydrophilic extracellular domain, suggesting adaptation to host immune responses. In contrast, exhibited strong negative selection, indicating functional conservation. Phylogenetic analyses revealed that and provide higher resolution than the 16S rRNA gene, enabling finer differentiation within subgroups. These findings highlight the potential of and as complementary markers for phytoplasma classification and diagnostics.
X病组（16SrIII）植原体是南美洲具有经济重要性的病原体，会导致严重的作物损失。基于16S rRNA基因的传统分类在区分密切相关菌株方面存在局限性，这促使人们探索替代标记。本研究聚焦于免疫显性膜蛋白imp和idpA，它们具有高度变异性，在宿主-病原体相互作用中发挥关键作用。通过对16SrIII亚组中 和 基因的分子特征分析，我们识别出显著的遗传多样性和不同的进化压力。处于正选择下的 基因，在其亲水性细胞外结构域表现出高变异性，表明其对宿主免疫反应的适应性。相比之下， 表现出强烈的负选择，表明其功能保守性。系统发育分析表明， 和 比16S rRNA基因具有更高的分辨率，能够在亚组内实现更精细的区分。这些发现凸显了 和 作为植原体分类和诊断的互补标记的潜力。
