Genes controlled by OS-2 MAP kinase activated by salt stress, antifungal fludioxonil, and heat in Neurospora crassa

Expression of six genes related to glycerol synthesis, gluconeogenesis, and catalase was activated in response to osmotic stress in the wild-type strain, but not in the os-2 mutant.

• The two-component signal transduction system involving OS-1, OS-4, OS-5, and OS-2 is important for osmotic regulation in Neurospora crassa.
• Quantitative real-time RT-PCR analysis identified genes regulated downstream of the OS-2 MAP kinase.
• The wild-type strain showed increased expression of genes related to glycerol synthesis and gluconeogenesis when exposed to osmotic stress and fludioxonil.
• A heat shock treatment similarly induced expression of these genes in the wild-type strain.
• Glycerol dehydrogenase activity increased in response to osmotic stress and fludioxonil in the wild-type strain, indicating a functional response to stress.
• OS-2 phosphorylation occurs due to the OS-1 cascade under low osmotic stress and fludioxonil, while non-OS-1 signaling can activate OS-2 in an OS-4-dependent manner under heat shock and higher osmotic stress.

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