Abstract
Reproductive mode can impact population genetic dynamics and evolutionary landscape of plant pathogens as well as on disease epidemiology and management. In this study, we monitored the spatial dynamics and mating type idiomorphs in ~700 Alternaria alternata isolates sampled from the main potato production areas in China to infer the mating system of potato early blight. Consistent with the expectation of asexual species, identical genotypes were recovered from different locations separated by hundreds of kilometers of geographic distance and spanned across many years. However, high genotype diversity, equal MAT1-1 and MAT1-2 frequencies within and among populations, no genetic differentiation and phylogenetic association between two mating types, combined with random association amongst neutral markers in some field populations, suggested that sexual reproduction may also play an important role in the epidemics and evolution of the pathogen in at least half of the populations assayed despite the fact that no teleomorphs have been observed yet naturally or artificially. Our results indicated that A. alternata may adopt an epidemic mode of reproduction by combining many cycles of asexual propagation with fewer cycles of sexual reproduction, facilitating its adaptation to changing environments and making the disease management on potato fields even more difficult.
Highlights
Associations amongst neutral loci indicate that the pathogen population may undergo regular sexual recombination[21,22,23]
Heterothallic pathogens with regular cycles of sexual reproduction are expected to have the two mating types present in equal frequencies in a population as a result of frequency dependency[22,25], and low genetic differentiation and no phylogenetic associations between isolates in the two mating type groups attributed to the frequent exchange of genetic material
We used population genetic approach to investigate the occurrence of cryptic sexual reproduction in the plant pathogenic fungus Alternaria alternata, which is associated with the early blight disease on potatoes
Summary
Associations amongst neutral loci indicate that the pathogen population may undergo regular sexual recombination[21,22,23]. We used population genetic approach to investigate the occurrence of cryptic sexual reproduction in the plant pathogenic fungus Alternaria alternata, which is associated with the early blight disease on potatoes. Population genetic analysis on the spatial dynamics of genetic variation in A. alternata using the combination of highly polymorphic neutral markers such as SSR and functional genes such as the mating type gene is scarce, for A. alternata from potato Knowledge from this type of analysis is important for understanding the reproductive mode and adaptive potential of the pathogen, necessary in designing an effective and sustainable disease management program for controlling this emerging disease worldwide. The objectives of this study were: 1) to screen specific primers for the determination of mating types in A. alternata; 2) to determine spatial distribution of the two mating types in A. alternata populations; and 3) to infer the occurrence of sexual reproduction in the field populations of A. alternata
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
