Genetic interaction of the stress response factors ChAP1 and Skn7 in the maize pathogenCochliobolus heterostrophus

Abstract

The transcription factors ChAP1 and Skn7 of the maize pathogen Cochliobolus heterostrophus are orthologs of Yap1 and Skn7 in yeast, where they are predicted to work together in a complex. Previous work showed that in C. heterostrophus, as in yeast, ChAP1 accumulates in the nucleus in response to reactive oxygen species (ROS). The expression of genes whose products counteract oxidative stress depends on ChAP1, as shown by impaired ability of a Δchap1 mutant to induce these 'antioxidant' genes. In this study, we found that under oxidative stress, antioxidant gene expression is also partially impaired in the Δskn7 mutant but to a milder extent than in the Δchap1 mutant, whereas in the double mutant - Δchap1-Δskn7 - none of the tested genes was induced, with the exception of one catalase gene, CAT2. Both single mutants are capable of infecting the plant, showing similar virulence to the WT. The double mutant, however, showed clearly decreased virulence, pointing to additive contributions of ChAP1 and Skn7. Possible mechanisms are discussed, including additive regulation of gene expression by oxidative stress.

Genome‐wide functional characterization of putative peroxidases in the head blight fungus Fusarium graminearum

“…We found that multiple TFs ( FgAP1 , FgSKN7 , GzZC086 , GzZC236 , GzHOME001 and GzC2H010 ) co‐regulated the expression of FCA7 in response to oxidative stress, reflecting a complex network of transcriptional activators of antioxidant genes. A cooperative role of these TFs has been reported in previous studies (Calvo et al ., ; Mulford and Fassler, ; Shalaby et al ., ). In S. cerevisiae and C. heterostrophus , Yap1 and Skn7 cooperate to activate the expression of antioxidant genes in response to oxidative stress (Mulford and Fassler, ; Shalaby et al ., ).…”

“…A cooperative role of these TFs has been reported in previous studies (Calvo et al ., ; Mulford and Fassler, ; Shalaby et al ., ). In S. cerevisiae and C. heterostrophus , Yap1 and Skn7 cooperate to activate the expression of antioxidant genes in response to oxidative stress (Mulford and Fassler, ; Shalaby et al ., ). In F. graminearum , the genetic relationship between orthologues of Skn7 and Atf1 has been investigated (Jiang et al ., ).…”

Unraveling the Function of the Response Regulator BcSkn7 in the Stress Signaling Network of Botrytis cinerea

“…Because it has been shown in some fungi that genes that are regulated by Skn7 are also regulated by Ap1 (19,21,36,59), the regulatory function of both proteins was analyzed in B. cinerea. To gain a first impression, a set of OSR genes was selected for expression analyses via Northern blotting (thioredoxin reductase, trr1…”

Detection of Cochliobolus heterostrophus races in South China

“…The most important research progress on C. heterostrophus focuses on genome sequencing of races T and O Turgeon & Baker, 2007) and determination of essential genes required for synthesizing T-toxin in race T (Baker et al, 2006;Inderbitzin, Asvarak, & Turgeon, 2010). Many transcription factors are involved in stress response, toxin production or virulence regulation (Lev et al, 2005;Ronen, Shalaby, & Horwitz, 2013;Shalaby, Larkov, Lamdan, & Horwitz, 2013;Zhang et al, 2013;Bi, Wu, Zhu, & Gillian Turgeon, 2013;Ganem et al, 2004;Horwitz et al, 1999;Igbaria et al, 2008;Izumitsu et al, 2009;Lev, Sharon, Hadar, Ma, & Horwitz, 1999;Oide et al, 2010;Wu, Oide, Zhang, Choi, & Turgeon, 2012). Among race types, race O is the predominant agent of maize disease in China; maize resistance against race O is determined by quantitative trait locus (Balint-Kurti et al, 2007;Carson, Stuber, & Senior, 2004).…”