AUTHOR=Deng Jiahui , Zhang Ziya , Wang Xingli , Cao Yongni , Huang Huichuan , Wang Mo , Luo Qiong 

TITLE=Molecular basis for loss of virulence in Magnaporthe oryzae strain AM16

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1484214

DOI=10.3389/fpls.2024.1484214

ISSN=1664-462X

ABSTRACT=<p>The rapid virulence variation of <italic>Magnaporthe oryzae</italic> (<italic>M. oryzae</italic>) to rice is a big challenge for rice blast control. Even though many studies have been done by scientists all over the world, the mechanism of virulence variation in <italic>M. oryzae</italic> remains elusive. AM16, an avirulent <italic>M. oryzae</italic> strain reported in our previous study, provides an excellent entry point to explore the mechanism of virulence variation in <italic>M. oryzae</italic>. In this study, we found that the <italic>Pmk1</italic> and <italic>Mac1</italic> had specific mutations in strain AM16. The AM16 strains overexpressing <italic>Pmk1</italic><sup>Guy11</sup> or (and) <italic>Mac1</italic><sup>Guy11</sup> allele from strain Guy11 displayed significantly increasing conidiation, functional appressorium formation, and restoring pathogenicity to rice. Moreover, we observed that the strains overexpressing <italic>Mac1</italic><sup>Guy11</sup> had stronger conidia forming capacity than that of the strains overexpressing <italic>Pmk1</italic><sup>Guy11</sup>, while the appressorium formation rate of strains overexpressing <italic>Pmk1</italic><sup>Guy11</sup> was similar to that of strains overexpressing <italic>Pmk1</italic><sup>Guy11</sup>-<italic>Mac1</italic><sup>Guy11</sup>, much higher than that of the strains overexpressing <italic>Mac1</italic><sup>Guy11</sup>. Taken together, our results reveal that the natural mutation of <italic>Pmk1</italic> and <italic>Mac1</italic> genes are important, but not the sole cause, for the loss of virulence in strain AM16. The functional difference between Pmk1 and Mac1 in the growth and development of <italic>M. oryzae</italic> was first discovered, providing new insight into the pathogenic mechanism of <italic>M. oryzae</italic>.</p>