Cryptococcus neoformans sexual reproduction is controlled by a quorum sensing peptide

Abstract

Bacterial quorum sensing is a well-characterized communication system that governs a large variety of collective behaviours. By comparison, quorum sensing regulation in eukaryotic microbes remains poorly understood, especially its functional role in eukaryote-specific behaviours, such as sexual reproduction. Cryptococcus neoformans is a prevalent fungal pathogen that has two defined sexual cycles (bisexual and unisexual) and is a model organism for studying sexual reproduction in fungi. Here, we show that the quorum sensing peptide Qsp1 serves as an important signalling molecule for both forms of sexual reproduction. Qsp1 orchestrates various differentiation and molecular processes, including meiosis, the hallmark of sexual reproduction. It activates bisexual mating, at least in part through the control of pheromone, a signal necessary for bisexual activation. Notably, Qsp1 also plays a major role in the intercellular regulation of unisexual initiation and coordination, in which pheromone is not strictly required. Through a multi-layered genetic screening approach, we identified the atypical zinc finger regulator Cqs2 as an important component of the Qsp1 signalling cascade during both bisexual and unisexual reproduction. The absence of Cqs2 eliminates the Qsp1-stimulated mating response. Together, these findings extend the range of behaviours governed by quorum sensing to sexual development and meiosis.

Laccaria bicolor MiSSP8 is a small‐secreted protein decisive for the establishment of the ectomycorrhizal symbiosis

“…On the other hand, Ustilago maydis Rep1 protein is also cleaved by kexin-protease and has a structural role in the fungal cell wall (Wödsten et al, 1996;Teertstra et al, 2006). An 11 amino acid long peptide processed by KEX2 in Cryptococcus neoformans is required for virulence and to activate the sexual program (Homer et al, 2016;Tian et al, 2018). Since MiSSP8-RNAi lines are not impaired in hyphal growth or fungal cell-wall sensitivity, it is unlikely that MiSSP8 or its derived peptides are involved in fungal cell wall structure.…”

Cryptococcus neoformans Mating and Genetic Crosses

“…It has also been indicated that the presence of copper in media has a positive effect on mating. Additionally, use of glucosamine as the sole carbon source in nutrient-rich media as well as the presence of quorum-sensing peptides has been shown to induce filamentation in Cryptococcus in recent studies (Kent, Ortiz-Bermudez, Giles, & Hull, 2008;Tian et al, 2018;Xu et al, 2017;Xue, Tada, Dong, & Heitman, 2007).…”

Laccaria bicolor MiSSP8 is a small-secreted protein decisive for the establishment of the ectomycorrhizal symbiosis

“…Several fungal peptides are produced from KEX2-processed precursor proteins 504 Ustilago maydis Rep1 protein is also cleaved by kexin-protease and has a structural role in the 507 fungal cell wall (Wösten et al, 1996;Teertstra et al, 2006). A 11 amino acid long peptide 508 processed by KEX2 in Cryptococcus neoformans is required for virulence and to activate the 509 sexual program (Homer et al, 2016;Tian et al, 2018). Since MiSSP8-RNAi lines are not 510 impaired in hyphal growth or fungal cell-wall sensitivity, it is unlikely that MiSSP8 or its 511 derived peptides are involved in fungal cell wall structure.…”