The tetraspanin BcPls1 is required for appressorium‐mediated penetration ofBotrytis cinereainto host plant leaves

Abstract

SummaryAnimal tetraspanins are membrane proteins controlling cell adhesion, morphology and motility. In fungi, the tetraspanin MgPls1 controls an appressorial function required for the penetration of Magnaporthe grisea into host plants. An orthologue of MgPLS1 , BcPLS1 , was identified in the necrotrophic fungal plant pathogen Botrytis cinerea . We constructed a Bcpls1::bar null mutant by targeted gene replacement. Bcpls1::bar is not pathogenic on intact plant tissues of bean, tomato or rose, but it infects wounded plant tissues. Both wild type and Bcpls1::bar differentiate appressoria on plant and artificial surfaces, a process involving an arrest of polarized growth, apex swelling and its cell wall reinforcement. Although wild-type appressoria allowed the penetration of the fungus into the host plant within 6-12 h, no successful penetration events were observed with Bcpls1::bar , suggesting that its appressoria are not functional. An eGFP transcriptional fusion showed that BcPLS1 was specifically expressed in conidia, germ tubes and appressoria during host penetration. Our results indicate that BcPLS1 is required for the penetration of B. cinerea into intact host plants. The defect in pathogenicity of Bcpls1::bar also demonstrates that functional B. cinerea appressoria are required for a successful penetration process. As Bcpls1::bar and Mgpls1 D D D D ::hph penetration defects are similar, fungal tetraspanins are likely to be required for an essential appressorial function widespread among fungi.

Complex Genetics Control Natural Variation inArabidopsis thalianaResistance toBotrytis cinerea

“…This includes the ability of the fungus to penetrate the leaf surface, relevant to this study as plants were not wounded prior to inoculation, and possibly the extent of plant defense activation by attempted fungal penetration of the leaf surface. However, the loss of penetration-related enzymes, such as cutinase, or the ability to form penetration structures, such as appressoria, have not impaired B. cinerea pathogenicity in experimental settings van Kan et al 1997;Gourgues et al 2004). Loci associated with A. thaliana ''penetration'' mutants, whose defects allow inappropriate penetration of A. thaliana leaves by non-Arabidopsis pathogens, are not colocalized with B. cinerea early lesion QTL detected in this study (Collins et al 2003;Assaad et al 2004;Stein et al 2006).…”

NADPH oxidases regulate septin-mediated cytoskeletal remodeling during plant infection by the rice blast fungus

“…Given the distinct function of Nox2 in regulating septin-mediated F-actin reorganization, we were interested in identifying other potential components of the Nox2 complex that might be involved in its recruitment to the appressorium pore. Studies in M. oryzae, Podospora anserina, and Botrytis cinerea have highlighted a connection between Nox2 (NoxB) and the transmembrane tetraspanin protein, Pls1 (17)(18)(19). Mutants lacking PLS1 in these fungi strongly resemble nox2 (noxB) mutants, and there is a very close phylogenetic association between fungi possessing both Nox2 and Pls1 homologs (20).…”

Differentially expressed genes in healthy and plum pox virus-infected Nicotiana benthamiana plants

“…Th eir fungal homologs (tetraspanin-like proteins, TLPs) are essential for penetration of fungal pathogens into leaves of the host plants (Clergeot et al, 2001;Gourgues et al, 2004). Function of structurally similar plant TLPs is still unknown, their involvement in male gamete-related processes during pollination has been hypothesized.…”