Abstract

VALADEZ-MOCTEZUMA, E.; SAMAH, S.  and  FRAUSTO-ROMO, M.. Frequency and genetic variability of Fusarium oxysporum mating types. Polibotánica [online]. 2020, n.50, pp.31-46.  Epub Nov 25, 2020. ISSN 1405-2768.  https://doi.org/10.18387/polibotanica.50.3.

The genus Fusarium comprises a vast number of cosmopolitan species, many of which are important pathogens of crops of agronomic interest. Molecular analysis of mating type (MAT) genes is a useful tool to study reproductive lifestyles and relationships between species. The aim of the present research was to determine the type of MAT idiomorphs (MAT1-1 and/or MAT1-2) in Fusarium oxysporum, F. nygamai, F. thapsinum and F. verticillioides isolates obtained across 20 sites distributed in the central zone of Mexico affecting wheat and chickpea crops, and to evaluate their sequences variability. PCR reactions from 110 isolates revealed that 66 Fusarium isolates presented the MAT1-1 idiomorph and 44 isolates presented the MAT1-2 idiomorph, but no isolate showed both idiomorphs. MAT1-1 and MAT1-2 idiomorph, from the same or different Fusarium species, coincided in the same field of several sites. Selected sequences of both idiomorphs showed greater divergence between species than within the same species. These changes were greater in the noncoding regions than in the coding regions. The variation of the mating type genes and the coexistence of both idiomorphs in the same agricultural site, point to a potential future change in the virulence of Fusarium isolates. In general, these findings will help to better understand the genetic variability of some Fusarium species in Mexico.

Keywords : Chickpea; Idiomorphs; MAT1-1; MAT1-2; Wheat.