Historical Differentiation and Recent Hybridization in Natural Populations of the Nematode-Trapping Fungus <i>Arthrobotrys oligospora</i> in China

• Main Authors: Duanyong Zhou, Jianping Xu, Jianyong Dong, Haixia Li, Da Wang, Juan Gu, Ke-Qin Zhang, Ying Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Microorganisms
• Subjects: short tandem repeat; genetic differentiation; unique alleles; non-random recombination; phenotypic variation; nematicidal activity
• Online Access: https://www.mdpi.com/2076-2607/9/9/1919

Maintaining the effects of nematode-trapping fungi (NTF) agents in order to control plant-parasitic nematodes (PPNs) in different ecological environments has been a major challenge in biological control applications. To achieve such an objective, it is important to understand how populations of the biocontrol agent NTF are geographically and ecologically structured. A previous study reported evidence for ecological adaptation in the model NTF species <i>Arthrobotrys oligospora</i>. However, their large-scale geographic structure, patterns of gene flow, their potential phenotypic diversification, and host specialization remain largely unknown. In this study, we developed a new panel of 20 polymorphic short tandem repeat (STR) markers and analyzed 239 isolates of <i>A. oligospora</i> from 19 geographic populations in China. In addition, DNA sequences at six nuclear gene loci and strain mating types (MAT) were obtained for these strains. Our analyses suggest historical divergence within the <i>A. oligospora</i> population in China. The genetically differentiated populations also showed phenotypic differences that may be related to their ecological adaptations. Interestingly, our analyses identified evidence for recent dispersion and hybridization among the historically subdivided geographic populations in nature. Together, our results indicate a changing population structure of <i>A. oligospora</i> in China and that care must be taken in selecting the appropriate strains as biocontrol agents that can effectively reproduce in agriculture soil while maintaining their nematode-trapping ability.