BcSpl1, a cerato-platanin family protein, contributes to Botrytis cinerea virulence and elicits the hypersensitive response in the host

Abstract

Summary• Proteins belonging to the cerato-platanin family are small proteins with phytotoxic activity. A member of this family, BcSpl1, is one of the most abundant proteins in the Botrytis cinerea secretome.• Expression analysis of the bcspl1 gene revealed that the transcript is present in every condition studied, showing the highest level in planta at the late stages of infection. Expression of a second cerato-platanin gene found in the B. cinerea genome, bcspl2, was not detected in any condition.• Two bcspl1 knock-out mutants were generated and both showed reduced virulence in a variety of hosts.• bcspl1 was expressed in Pichia pastoris and the recombinant protein was able to cause a fast and strong necrosis when infiltrated in tomato, tobacco and Arabidopsis leaves, in a dose-dependent manner. The BcSpl1-treated plant tissues showed symptoms of the hypersensitive response such as induction of reactive oxygen species, electrolyte leakage, cytoplasm shrinkage, and cell autofluorescence, as well as the induction of defense genes considered to be markers of the hypersensitive response. The Arabidopsis bak1 mutation partially prevented the induction of necrosis in this plant by BcSpl1. Two different BcSpl1-derived 40-amino acids peptides were also active in inducing necrosis.

The Genomes of Three Uneven Siblings: Footprints of the Lifestyles of Three Trichoderma Species

“…For example, during the mutualistic T. virens-plant interaction, fungal CP elicitors Sm1 (TR_82662, TA_302952, and TV_110852) and Sm2 (TR_123955, TA_88590, and TV_111830) are secreted during the first stages of root sensing and induce systemic disease resistance, conferring resistance to phytopathogens (28,29,1271,1272). In contrast, CP virulence factor BcSpl1 from Botritys cinerea has a phytotoxic function in inducing necrosis on tobacco leaves (1273). Furthermore, CPs have also been recently classified as MAMPs/PAMPs for their role during host plant colonization (1270).…”

Cerato-platanin shows expansin-like activity on cellulosic materials

“…These proteins are grouped into a protein family of which CP is the first member (the "cerato-platanin family", Pfam PF07249), and like CP some of them are known for the resistance-inducing activity in plants (Djonović et al 2006;Frías et al 2011;Seidl et al 2006;Yang et al 2009;Zaparoli et al 2009). In the "ceratoplatanin family", the molecular mechanism of action on plants and above all the biological role in fungal life are little-known aspects.…”

Plant Innate Immunity: Perception of Conserved Microbial Signatures

“…Atbak1 mutants are impaired in the perception of a plethora of fungal-, bacterial-, and oomycete-derived conserved microbial signatures (36,70,179). Yet only the identification of the novel mutant allele atbak1-5, which is specifically impaired in PTI signaling without displaying any other pleiotropic defects in development or cell-death control, revealed that AtBAK1 contributes directly significantly to disease resistance against biotrophic and hemibiotrophic pathogens (179,187).…”