Apoptosis-like programmed cell death in the grey mould fungus Botrytis cinerea: genes and their role in pathogenicity

Abstract

<jats:p>A considerable number of fungal homologues of human apoptotic genes have been identified in recent years. Nevertheless, we are far from being able to connect the different pieces and construct a primary structure of the fungal apoptotic regulatory network. To get a better picture of the available fungal components, we generated an automatic search protocol that is based on protein sequences together with a domain-centred approach. We used this protocol to search all the available fungal databases for domains and homologues of human apoptotic proteins. Among all known apoptotic domains, only the BIR [baculovirus IAP (inhibitor of apoptosis protein) repeat] domain was found in fungi. A single protein with one or two BIR domains is present in most (but not all) fungal species. We isolated the BIR-containing protein from the grey mould fungus Botrytis cinerea and determined its role in apoptosis and pathogenicity. We also isolated and analysed BcNMA, a homologue of the yeast NMA11 gene. Partial knockout or overexpression strains of BcBIR1 confirmed that BcBir1 is anti-apoptotic and this activity was assigned to the N′-terminal part of the protein. Plant infection assays showed that the fungus undergoes massive PCD (programmed cell death) during early stages of infection. Further studies showed that fungal virulence was fully correlated with the ability of the fungus to cope with plant-induced PCD. Together, our result show that BcBir1 is a major regulator of PCD in B. cinerea and that proper regulation of the host-induced PCD is essential for pathogenesis in this and other similar fungal pathogens.</jats:p>

Characterization of the fungitoxic activity onBotrytis cinereaof the aristolochic acids I andII

“…This process of cell death has been described in yeasts and some filamentous fungi, including B. cinerea (Shlezinger et al . ; Cotoras et al . ).…”

“…In fungi, the degradation of DNA has been considered as a sign of apoptosis phenotype (Shlezinger et al . ), therefore in this work, the effect of the aristolochic acid mixture (54% AAI and 46% AAII) on the DNA integrity in hypha of B. cinerea was determined (Fig. ).…”

Apoptotic-like programed cell death in fungi: the benefits in filamentous species

“…In many cases, homology with the entire animal ortholog is rather low or restricted to a specific domain and hence simple BLAST searches might not be sensitive enough to recognize the homology. In order to obtain a deeper coverage of the putative fungal PCD orthologs, a computer-guided approach was developed, which enables automatic searches of all available fungal genomes for presence of homologs of apoptotic proteins or domains (Shlezinger et al, 2011a). Using this approach, it is possible to identify all the fungal genes that are putative homologs of known apoptotic genes or that contain a putative apoptotic domain.…”

Plant phenolic acids induce programmed cell death of a fungal pathogen: MAPK signaling and survival of Cochliobolus heterostrophus

“…This occurs despite the fact that these are compatible interactions in which the pathogen overcomes the plant defenses. Some specific plant antimicrobial compounds have been shown to induce PCD in fungal pathogens, for example the peptide osmotin (Narasimhan et al ., ), and the secondary metabolites α‐tomatine (Ito et al ., ) and camalexin (Shlezinger et al ., ). Farnesol, released by Candida albicans , causes PCD of Aspergillus nidulans , so this principle applies to antagonistic fungal‐fungal interactions as well (Semighini et al ., ).…”