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bioRxiv · 10.1101/2022.07.07.499222

A fungal secondary metabolism gene cluster enables mutualist-pathogen transition in root endophyte Colletotrichum tofieldiae

Hiruma, K.·Aoki, S.·Utami, Y. D.·Okamoto, M.·Kawamura, N.·Nakamura, M.·Ohmori, Y.·Sugita, R.·Tanoi, K.·Sato, T.·Iwasaki, W.·Saijo, Y.
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Abstract

Plant-associated fungi show diverse lifestyles from pathogenic to mutualistic to the host; however, the principles and mechanisms through which they shift the lifestyles require elucidation. The root fungus Colletotrichum tofieldiae (Ct) promotes Arabidopsis thaliana growth under phosphate limiting conditions. We reveal a Ct strain, designated Ct3, that severely inhibits plant growth. Ct3 pathogenesis occurs through activation of host abscisic acid (ABA) pathways via a fungal secondary metabolism gene cluster related to sesquiterpene ABA and botrydial (BOT) biosynthesis. ABA-BOT cluster activation during root infection suppresses host nutrient uptake-related genes and changes the mineral contents, suggesting its role in manipulating host nutrition states. Conversely, disruption or environmental suppression of the cluster renders Ct3 beneficial for plant growth, in a manner dependent on host phosphate starvation response regulators. Our findings indicate that a fungal metabolism cluster provides a means by which infectious fungi modulate lifestyles along the parasitic-mutualistic continuum in fluctuating environments.

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Hiruma, K., Aoki, S., Utami, Y. D., Okamoto, M., Kawamura, N., Nakamura, M., Ohmori, Y., Sugita, R., Tanoi, K., Sato, T., Iwasaki, W., Saijo, Y.. 2022-07-08. A fungal secondary metabolism gene cluster enables mutualist-pathogen transition in root endophyte Colletotrichum tofieldiae. https://doi.org/10.1101/2022.07.07.499222

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