HOM2 and TPK1 are associated with Kluyveromyces marxianus growth under high-temperature and reduced-aeration conditions.

Kluyveromyces marxianus (K. marxianus) holds significant application potential in biomanufacturing. However, in industrial processes, high temperature and reduced aeration often occur and severely constrain its fermentation performance. The molecular mechanisms underlying yeast responses to these stresses remain to be fully elucidated. In this study, transcriptomic analysis combined with Weighted Gene Co-expression Network Analysis (WGCNA) was performed to characterize the global gene expression profiles of K. marxianus under high-temperature or reduced-aeration conditions. Co-expression network and qPCR expression analysis identified two core hub genes, TPK1 encoding the catalytic subunit of cAMP-dependent protein kinase, and HOM2 encoding aspartate-semialdehyde dehydrogenase. The gene knockout experiments revealed that deletion of TPK1 or HOM2 lead to reduced maximum specific growth rate (µmax), decreased cell wall integrity and exacerbated membrane damage. Conversely, overexpression of these genes significantly increased µmax and enhanced stress tolerance. By genetic and chemical comparisons, this study identified TPK1 and HOM2 as candidate hub genes involved in yeast adaptation to high temperature and reduced aeration conditions, providing new insights into yeast's stress-responsive regulatory mechanisms and offering valuable key genetic targets for the engineering of robust industrial yeast chassis.