Fg K in1 kinase localizes to the septal pore and plays a role in hyphal growth, ascospore germination, pathogenesis, and localization of T ub1 beta‐tubulins in F usarium graminearum

Summary The K in1/Par‐1/ MARK kinases regulate various cellular processes in eukaryotic organisms. K in1 orthologs are well conserved in fungal pathogens but none of them have been functionally characterized. Here, we show that KIN 1 is important for pathogenesis and growth in two phytopathogenic fungi and that F gKin1 regulates ascospore germination and the localization of T ub1 β‐tubulins in F usarium graminearum . The F gkin1 mutant and putative F g KIN 1 S172A kinase dead (nonactivatable) transformants were characterized for defects in plant infection, sexual and asexual reproduction, and stress responses. The localization of F gKin1 and two β‐tubulins were examined in the wild‐type and mutant backgrounds. Deletion of F g KIN 1 resulted in reduced virulence and defects in ascospore germination and release. F g K in1 localized to the center of septal pores. F g KIN 1 deletion had no effect on T ub2 microtubules but disrupted T ub1 localization. In the mutant, Tub1 appeared to be enriched in the nucleolus. In M agnaporthe oryzae , M oKin1 has similar functions in growth and infection and it also localizes to septal pores. The S 172A mutation had no effect on the localization and function of Fg KIN 1 during sexual reproduction. These results indicate that F g KIN 1 has kinase‐dependent and independent functions and it specifically regulates T ub1 β‐tubulins. F gKin1 plays a critical role in ascospore discharge, germination, and plant infection.