CgHog1 controls the adaptation to both sorbitol and fludioxonil in Colletotrichum gloeosporioides

Abstract

The HOG (high-osmolarity glycerol) pathway is critical for the appropriate adaptation to adverse conditions. Here, we demonstrated that the deletion of CgHog1 resulted in enhanced sensitivity to osmotic stress and increased resistance to fludioxonil in the poplar anthracnose fungus Colletotrichum gloeosporioides. The accumulation of chitin around hyphal tips was obviously decreased in the ΔCgHog1 strain under sorbitol, whereas it strongly was increased in the response to fludioxonil compared with the wild type. To investigate the underlying mechanism of CgHog1-mediated adaption to osmotic stress and fludioxonil, transcriptomic profiles were performed in both the ΔCgHog1 strain and the wild type under the treatment of sorbitol and fludioxonil, respectively. Under sorbitol, genes associated with glycolysis, lipid metabolism, and accumulation of soluble sugars and amino acids were differentially expressed; under fludioxonil, vesicle trafficking-related genes were highly downregulated in the ΔCgHog1 strain, which was consistent with abnormal vacuoles distribution and morphology of hyphae, indicating that the growth defect caused by fludioxonil may be associated with disruption of endocytosis. Taken together, we elucidated the adaptation mechanisms of how CgHog1 regulates appropriate response to sorbitol and fludioxonil via different metabolism pathways. These findings extend our insights into the HOG pathway in fungi.

Keywords: Adaption; CgHog1; Colletotrichum gloeosporioides; Fludioxonil; Osmotic stress; Transcriptome.