Sparks Adam H, Adorada Dante L, Colombi Elena, Kelly Lisa A, Young Anthony, Knight Noel L, Vaghefi Niloofar
Curtin University, Centre for Crop and Disease Management, Kent St, Bentley, Western Australia, Australia, 6051.
University of Southern Queensland, Centre for Crop Health, West St, Toowoomba, Queensland, Australia, 4350;
Phytopathology. 2025 Jun 4. doi: 10.1094/PHYTO-01-25-0032-R.
Pathogens can evolve rapidly, leading to the emergence of novel strains that can overcome commercially deployed host plant resistance. Understanding the genetic and phenotypic diversity and population dynamics of plant pathogens is crucial to inform breeding programs targeting resistance. Tan spot, otherwise known as bacterial wilt, caused by pv. , is an increasingly significant pathogen affecting beans and mungbean worldwide. Since the 1990s, several mungbean cultivars with partial resistance to tan spot have been released in Australia; however, cultivars initially rated as moderately resistant were later rated as moderately susceptible to tan spot. This study investigated the genetic and phenotypic diversity and temporal evolutionary dynamics of pv. in Australian mungbean fields. Whole-genome sequencing of 119 isolates collected from mungbean and other legumes (1986 to 2019) enabled analyses of pathogen evolution in Australia and in a global context. Results revealed that clonal expansion from standing genetic variation, rather than introduction of novel genotypes, has driven the evolution of this pathogen in Australia since the 1980s. Glasshouse trials confirmed the role of a plasmid in pathogenicity of pv. but found no significant differences in aggressiveness between clonal lineages. Our research provides insights into genetic and phenotypic diversity of this important plant pathogen and temporal changes in its population structure in Australia and highlights the need for further studies on the competitive fitness of isolates and characterisation of private alleles linked to dominant clonal lineages.
病原体能够迅速进化，导致新菌株出现，这些新菌株能够克服商业种植的宿主植物抗性。了解植物病原体的遗传和表型多样性以及种群动态对于指导抗性病育种计划至关重要。由[具体病原菌名称]引起的褐斑病，也称为青枯病，是一种在全球范围内对豆类和绿豆影响日益显著的病原体。自20世纪90年代以来，澳大利亚已发布了几种对褐斑病具有部分抗性的绿豆品种；然而，最初被评为中度抗性的品种后来被评为对褐斑病中度敏感。本研究调查了澳大利亚绿豆田中[具体病原菌名称]的遗传和表型多样性以及时间进化动态。对从绿豆和其他豆类收集的119个分离株（1986年至2019年）进行全基因组测序，能够在澳大利亚和全球范围内分析病原体的进化。结果表明，自20世纪80年代以来，该病原体在澳大利亚的进化是由现有遗传变异的克隆扩增驱动的，而不是新基因型的引入。温室试验证实了一种质粒在[具体病原菌名称]致病性中的作用，但发现克隆谱系之间的侵袭力没有显著差异。我们的研究提供了对这种重要植物病原体的遗传和表型多样性及其在澳大利亚种群结构随时间变化的见解，并强调需要进一步研究分离株的竞争适应性以及与优势克隆谱系相关的私有等位基因的特征。
