The MaCreA Gene Regulates Normal Conidiation and Microcycle Conidiation in Metarhizium acridum

Abstract

As a C 2 H 2 type zinc finger transcription factor, CreA is the key in Carbon Catabolism Repression (CCR) pathway, which negatively regulates the genes in carbon sources utilization. As conidiation in filamentous fungi is affected by nutritional conditions, CreA may contribute to fungal conidiation, which has been well studied in filamentous fungi, especially Aspergillus spp., but researches on entomopathogenic fungi are not enough. In this study, we found a homologous gene MaCreA in Metarhizium acridum , and the MaCreA deletion strain showed delayed conidiation, significant decrease in conidial yield, and 96.88% lower conidial production, when compared with the wild-type strain, and the normal conidiation and microcycle conidiation pattern shift was blocked. RT-qPCR showed that the transcription levels of the genes FlbD and LaeA (related to asexual development) were significantly altered, and those of most of the conidiation-related genes were higher in Δ MaCreA strain. The results of RNA-Seq revealed that MaCreA regulated the two conidiation patterns by mediating genes related to cell cycle, cell division, cell wall, and cell polarity. In conclusion, CreA , as a core regulatory gene in conidiation, provides new insight into the mechanism of conidiation in entomopathogenic fungi.

Principal component analysis of the biological characteristics of entomopathogenic fungi in nutrient‐limited and cuticle‐based media

“…Likewise, the limitation of nutrients in the fungus was decisive to induce conidiation, and affect its virulence. In fact, the nutrient limitation has been described as a strong inducer of the expression of genes involved in sporulation [23,24], in the expression of enzymes involved in virulence, and in nutrient metabolism [7,10,25].…”

The carbon catabolite repressor CreA is an essential virulence factor of Metarhizium acridum against Locusta migratoria

“…The MaCreA deleted strain (ΔMaCreA) and MaCreA complementary strain (CP) has been obtained before. 28 Locusta migratoria was provided by the Center of Genetic Engineering, School of Life Sciences, Chongqing University.…”

“…In M. acridum, a previous study revealed MaCreA gene regulated two conidiation pattern shift, showing the significant delay of conidiation process and the decline of conidial yield of ΔMaCreA, 28 but the effects of this gene on virulence remains unknown. This study found that the virulence of ΔMaCreA strain reduced significantly and explored the roles of MaCreA in virulence regulation.…”

MaNsdD regulates conidiation negatively by inhibiting the AbaA expression required for normal conidiation in Metarhizium acridum

“…Some genes are involved in microcycle conidiation, such as Mcb and Mcm in Neurospora crassa (Maheshwari, 1991), VeA and WetA in Fusarium (Li et al ., 2006; Son et al ., 2014), and MaH1 , CreA , Sho1 and Msn2 in M . acridum (Gao et al ., 2019; Song et al ., 2019; Zhao et al ., 2020; Song et al ., 2021). However, the regulatory mechanism of microcycle conidiation is still largely unknown.…”