The CfMcm1 Regulates Pathogenicity, Conidium Germination, and Sexual Development in Colletotrichum fructicola

Abstract

Glomerella leaf spot (GLS) caused by Colletotrichum fructicola is a severe disease worldwide on apple, causing defoliation, leaf and fruit spot, and substantial yield loss. However, little is known about its molecular mechanisms of pathogenesis. Previous transcriptome analysis revealed that a transcription factor, CfMcm1, was induced during leaf infection. In the present work, expression pattern analysis verified that CfMcm1 gene was strongly expressed in conidia and early infection. Phenotypic analysis revealed that the gene deletion mutant ΔCfMcm1 lost pathogenicity to apple leaves by inhibiting conidial germination and appressorium formation. Besides appressorium-mediated pathogenicity, ΔCfMcm1 colonization and hyphal extension in wounded apple fruit was also reduced, and conidial germination mode and conidial color were altered. ΔCfMcm1 displayed impairment of cell wall integrity and response to stress caused by oxidation, osmosis and an acid environment. Furthermore, the deletion mutant produced fewer and smaller perithecia and no ascospores. In contrast, melanin deposition in mycelia of ΔCfMcm1 was strengthened. Further comparative transcriptome and quantitative PCR analysis revealed that CfMcm1 modulated expression of genes related to conidial development (CfERG5A, CfERG5B, CfHik5, CfAbaA), appressorium formation (CfCBP1, CfCHS7), pectin degradation (CfPelA, CfPelB), sexual development (CfMYB, CfFork, CfHMG, CfMAT1-2-1) and melanin biosynthesis (CfCmr1, CfPKS1, CfT4HR1, CfTHR1, CfSCD1). Our results demonstrated that CfMcm1 is a pivotal regulator possessing multiple functions in pathogenicity, asexual and sexual reproduction, and melanin biosynthesis.

Mutations in Podospora anserina MCM1 and VelC Trigger Spontaneous Development of Barren Fruiting Bodies

“…In S. macrospora, as shown here in P. anserina, MCM1 controls different development processes and is essential for the formation of perithecia [47,48]. A similar role has been evidenced in A. nidulans [49], Fusarium graminearum [50], and Colletotrichun fructicola [51]. In the phytopathogen M. oryzae, the gene MoMCM1 was shown to be required for appressorial penetration and male fertility, but it does seem to be involved in fruiting body formation [52].…”

Draft genome sequence of Colletotrichum fructicola causing leaf spot on tea plants (Camellia sinensis)

“…In the C. gloeosporioides complex, C. fructicola is one of the most aggressive species, and affects a wide range of plants, such as kiwifruit, cherry, apple and tea plants (Huang, Sheng, et al, 2022;Huang, Wu, et al, 2022;Liu et al, 2022;Lu et al, 2018;Tan et al, 2021;Tang et al, 2021;Zhang et al, 2022). In tea plants, based on the high isolation rate from the main tea region in China, C. fructicola and C. camelliae were identified as the dominant pathogens causing anthracnose disease (Lu et al, 2018).…”

“…It forms penetration pegs from specialized melanized appressoria to penetrate epidermal cells of host plants, and then differentiates bulbous biotrophic hyphae across living host cells before switching to a necrotrophic stage featuring formation of secondary hyphae that can kill and destroy host tissues (Liang et al, 2018; Münch et al, 2008; O'Connell et al, 2012; Shang et al, 2020). In the process of successful invasion, some factors, such as carbohydrate‐active enzymes and secreted proteins, facilitate hyphal penetration and play necessary roles (Liu et al, 2022; Velho et al, 2018).…”