Coregulation of dimorphism and symbiosis by cyclic AMP signaling in the lichenized fungus <i>Umbilicaria muhlenbergii</i>
Yanyan Wang, Xinli Wei, Zhuyun Bian, Jiangchun Wei, Jin‐Rong Xu
Abstract
Significance Umbilicaria muhlenbergii is the only lichenized species known to be dimorphic in culture. This study showed that yeast-to-pseudohypha transition in U. muhlenbergii is associated with symbiosis and regulated by the cAMP-PKA (protein kinase A) pathway. Treatments with a cAMP diphosphoesterase inhibitor induced pseudohyphal/hyphal growth and differentiation of lichen cortex-like tissues. Two Gα subunits were functionally characterized to show the regulation of dimorphism by UmGPA3 . This is a report on identifying genes important for development and symbiosis in lichenized fungi. This is also a report of generating targeted gene deletion mutants in U. muhlenbergii and Lecanoromycetes in general. Because of its relatively fast growth rate and amenability to molecular manipulations, U. muhlenbergii is uniquely suited for studying fungal–algal interactions and initial symbiotic interactions.