Genome-wide transcriptional profiling of Botrytis cinerea genes targeting plant cell walls during infections of different hosts

Abstract

Cell walls are barriers that impair colonization of host tissues, but also are important reservoirs of energy-rich sugars. Growing hyphae of necrotrophic fungal pathogens, such as Botrytis cinerea (Botrytis, henceforth), secrete enzymes that disassemble cell wall polysaccharides. In this work we describe the annotation of 275 putative secreted Carbohydrate-Active enZymes (CAZymes) identified in the Botrytis B05.10 genome. Using RNAseq we determined which Botrytis CAZymes were expressed during infections of lettuce leaves, ripe tomato fruit, and grape berries. On the three hosts, Botrytis expressed a common group of 229 potentially secreted CAZymes, including 28 pectin backbone-modifying enzymes, 21 hemicellulose-modifying proteins, 18 enzymes that might target pectin and hemicellulose side-branches, and 16 enzymes predicted to degrade cellulose. The diversity of the Botrytis CAZymes may be partly responsible for its wide host range. Thirty-six candidate CAZymes with secretion signals were found exclusively when Botrytis interacted with ripe tomato fruit and grape berries. Pectin polysaccharides are notably abundant in grape and tomato cell walls, but lettuce leaf walls have less pectin and are richer in hemicelluloses and cellulose. The results of this study not only suggest that Botrytis targets similar wall polysaccharide networks on fruit and leaves, but also that it may selectively attack host wall polysaccharide substrates depending on the host tissue.

WITHDRAWN: Identification of an endogenous redox partner for lytic polysaccharide monooxygenase-based oxidative cleavage of polysaccharides

“…Aforementioned studies has also revealed that under cellulose induced condition, the strain has shown preponderance of LPMOs in its secretome (23,36). In our study, we have found that B. cinerea genome harbors nine homologues of LPMOs, seven are upregulated upon cellulosic inductions at transcripts level (Fig 2A).…”

“…Out of five interacting proteins identified, two were annotated as cellobiose dehydrogenases, and rest belong to proteolytic superfamily. We negated proteolytic proteins such as Prolyl aminopeptidase, Aspartic protease, Pectin methyl esterase, from the list of interacting partner because of two prime reasons: First, secretome of B. cinerea is already enriched with proteases and hydrolases (23) and thus there is high probability of finding these proteins as contaminants in the pull down assays, secondly, these proteolytic protein lack electron donor tendencies. Therefore, two identified cellobiose dehydrogenases i.e., CDH_53425 and CDH_52080 were further analysed to identify potential reductant partner.…”

“…Therefore, we aimed at holistic approach to identify and characterize endogenous redox partner of fungal LPMO from whole secretome in one of the model system i.e. Botrytis cinerea (B. cinerea), as its supernatant has already shown preponderance of LPMOs (23). Quantitative RNA and protein expression data were utilized to identify cellulose inducible AA9 LPMO encoding gene from B. cinerea.…”

Changes in the Sclerotinia sclerotiorum transcriptome during infection of Brassica napus

“…In the S. sclerotiorum – P. vulgaris interaction, SS1G_01493 (beta-xylosidase) was up-regulated during the early stages before the emergence of visible necrotic symptoms on the stem, whereas genes encoding cellulose-degrading enzymes, SS1G_13255 (beta-1,4-glucanase) and SS1G_07146 (cellobiohydrolase), were induced during the later stages of infection coinciding with the formation of visible stem lesions [40]. In B. cinerea , the expression patterns of genes encoding xyloglucan-degrading enzymes was found to be vastly different dependent upon the host plant [58]. …”

Plant cell wall in pathogenesis, parasitism and symbiosis

“…Necrotrophic fungi produce several cell wall degrading enzymes (CWDEs) to degrade plant cell wall polysaccharides that favor plant colonization. Blanco-Ulate and co-authors present a genome-wide transcriptional profiling of Botrytis cinerea CWDEs expressed during infection of important nutritional resources such as lettuce leaves, ripe tomato fruit, and grape berries (Blanco-Ulate et al, 2014).…”