Sas3-mediated histone acetylation regulates effector gene activation in a fungal plant pathogen

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Effector proteins are secreted by plant pathogens to enable host colonization. Typically, effector genes are tightly regulated, have very low expression levelsin axenic conditions, and are strongly induced during host colonization. Chromatin remodeling contributes to the activation of effector genes in planta by still poorly known mechanisms. In this work we investigated the role of histone acetylation in effector gene derepression in plant pathogens. We used Zymoseptoria tritici, a major pathogen of wheat, as a model to determine the role of lysine acetyltransferases (KATs) in plant infection. We showed that effector gene activation is associated with chromatin remodeling, featuring increased acetylation levels of histone H3 lysine 9 (H3K9) and 14 (H3K14) in effector loci. We functionally characterized the role of Z. tritici KATs and demonstrated their distinct contributions to growth, development, and infection. Sas3 is required for host colonization and pycnidia production, while Gcn5 has a major role in pycnidia production. Furthermore, we demonstrated that Sas3 is involved in acetylation of H3K9 and H3K14 in effector loci and in effector gene activation during plant infection. We propose that Sas3- mediated histone acetylation is required for spatiotemporal activation of effector genes and virulence of Z. tritici

The research was financed by the Ministry of Science and Innovation (Grant PID2019-108693RA-I00 financed by MICIN/AEI/ to AS-V). ASV was recipient of Ramon y Cajal grant RYC2018-025530-I of Spanish Ministry of Science, Innovation and Universities (MCIN/AEI/ and El FSE). MSF was recipient of Margarita Salas financed by the European Union - Next Generation EU (Grant MARSALAS21-31).

Peer reviewed