ToxA , a significant virulence factor involved in wheat spot blotch disease, exists in the Mexican population of Bipolaris sorokiniana uri icon


  • Spot blotch, caused by the pathogenBipolaris sorokiniana, is an important foliar disease of wheat in warm and humid regions worldwide. The fungal virulence factorToxAinteracts withTsn1in wheat and leads to a susceptible reaction.ToxAhas been found inB. sorokinianapopulations of Australia, the USA, and India, and here we report its occurrence in Mexico, based on analysis of a collection of 196 Mexican isolates ofB. sorokiniana. The isolates were collected from experimental stations and farmers' fields in nine states of Mexico, during the period from 1992 to 2017. A PCR assay with theToxA-specific marker was conducted, and the results revealed the presence ofToxAin 20 isolates (10.2%). Culture filtrate infiltration experiments confirmed that all the 20 isolates were able to induce necrosis reaction on Glenlea, a wheat genotype withTsn1. This is the first report on the occurrence ofToxAin MexicanB. sorokinianapopulation, which is key information for breeding wheat for resistance against spot blotch.

publication date

  • 2021
  • 2020