Caenorhabditis elegans as a model to study effector proteins of citrus pathogens

SCATTOLINI ALBERTINA; MOLINA MARÍA CELESTE; MANSILLA MARÍA CECILIA; MARANO MARIA ROSA; GARCÍA LUCILA

Rosario

Congreso; 2nd Latin American Worm Meeting; 2020

Latin American Worm Society

Candidatus Liberibacter (CaL) is the causal agent of Huanglongbing; the most devastating citrus disease. Genomic analysis of CaL species provided evidence of the existence of putative effector proteins that may be involved in virulence. Clibasia_01345 was identified as a serralysin-like protein in CaL species. Serralaysins are considered virulence factors during bacterial infection of eukaryotic cells. Expression levels of Clibasia_01345 are increased when CaL moves from the psyllid (vector) to the citrus phloem, suggesting a function within the infection process. However, the non-culturability of CaL species limits our knowledge on this process, where effector proteins must be secreted by surrogate models. C. elegans was previously reported as a feasible model to study plant pathogens like Xanthomonas oryzae. Here we propose X. citri-C. elegans interaction as a heterologous system to study CaL effector proteins. Therefore, we first determined the lifespan of worms by replacing E. coli OP50 with X. citri as food supply. X. citri decreased the lifespan compared to the control and it was shorter than that shown for X. oryzae. However, when worms were fed with X. citri cells expressing Clibasia_01345, the survival time was extended from 2 to 6 days. Preliminary results suggesting that Clibasia_01345 expression modifies the extracellular matrix of X. citri led us to ask ourselves whether the extended lifespan was due to Clibasia_01345 or to the modified extracellular matrix. Similar survival rates were observed when worms were fed either with E. coli expressing Clibasia_01345 or with the control cells. Our results suggest that extracellular matrix composition could be involved in the suppression of defense response in C. elegans.