Fungi frequently encounter nutrient limitation, osmotic stress, oxidative pressure, light fluctuations, temperature shifts, and host-associated stresses. Rather than responding passively to deteriorating environments, many fungi actively redirect development from vegetative growth toward asexual sporulation, sexual reproduction, or resting structure formation. These transitions promote dispersal, dormancy, stress resistance, or genetic diversification, but they are not governed by a single conserved stress-response pathway. Instead, conserved nutrient- and stress-sensing modules are integrated with lineage-specific developmental circuits. This review synthesizes recent advances in understanding how environmental stress, particularly nutrient limitation, regulates fungal reproductive development. We discuss nutrient limitation as both a physiological constraint and a developmental signal, and compare regulatory mechanisms across yeasts, filamentous ascomycetes, and pathogenic fungi. Major pathways and regulatory layers include cAMP-PKA, TOR, HOG MAPK signaling, light-responsive systems, the Velvet complex, chromatin regulation, diffusible chemical signals, and sexual-stage-specific adenosine-to-inosine (A-to-I) mRNA editing. Together, these mechanisms determine whether fungi remain vegetative or commit to reproduction. We also evaluate why sexual reproduction may be favored under stressful or low-fitness conditions. While asexual spores and resting structures can enhance survival and dispersal, costly meiotic reproduction may be promoted when recombination allows offspring or alleles to escape maladapted genetic backgrounds. Fitness-associated sex and abandon-ship models therefore provide useful evolutionary frameworks for interpreting stress-induced reproduction. Understanding these mechanisms is timely and important because fungal reproductive switching affects industrial spore production, pathogen transmission, disease management, and evolutionary potential. Future progress will require causal, ecologically grounded models linking environmental perception, molecular regulation, reproductive output, and fitness consequences.

• PMID: 42547696
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Reference Type

Journal Article | Review

Authors

Yang J, Wang Q, Liu H

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Review For