Data from: Tracking changes in life-history traits related to unnecessary virulence in a plant-parasitic nematode

Evaluating trade-offs in life-history traits of plant pathogens is essential to understand the evolution and epidemiology of diseases. In particular, virulence costs when the corresponding host resistance gene is lacking play a major role in the adaptive biology of pathogens and contribute to the maintenance of their genetic diversity. Here, we investigated whether life-history traits directly linked to the establishment of plant–nematode interactions, that is, ability to locate and move toward the roots of the host plant, and to invade roots and develop into mature females, are affected in Meloidogyne incognita lines virulent against the tomato Mi-1.2 resistance gene. Virulent and avirulent near-isogenic lines only differing in their capacity to reproduce or not on resistant tomatoes were compared in single inoculation or pairwise competition experiments. Data highlighted (1) a global lack of trade-off in traits associated with unnecessary virulence with respect to the nematode ability to successfully infest plant roots and (2) variability in these traits when the genetic background of the nematode is considered irrespective of its (a)virulence status. These data suggest that the variation detected here is independent from the adaptation of M. incognita to host resistance, but rather reflects some genetic polymorphism in this asexual organism.

解析植物病原体生活史性状间的权衡关系，对于阐明病害的演化与流行规律至关重要。具体而言，当缺失对应寄主抗病基因时的毒力代价，在病原体的适应性生物学中占据核心地位，并有助于维持其遗传多样性。本研究针对能够克服番茄Mi-1.2抗病基因的南方根结线虫（Meloidogyne incognita）品系，探究与植物-线虫互作建立直接相关的生活史性状——即定位并向寄主植物根系移动、侵入根系并发育为成熟雌虫的能力——是否受到影响。研究选取仅在抗病番茄上的繁殖能力存在差异的强毒力与无毒性近等基因系，通过单接种实验与两两竞争实验开展对比分析。实验结果显示：其一，在线虫成功侵染植物根系的相关性状中，与非必需毒力相关的权衡关系整体缺失；其二，无论线虫的（无）毒力状态如何，当其遗传背景存在差异时，上述性状均存在变异。上述结果表明，本研究中检测到的性状变异与南方根结线虫对寄主抗病性的适应性无关，而是反映了该无性生殖生物体内存在的部分遗传多态性。