Knockdown of a mucin-like gene in Meloidogyne incognita (Nematoda) decreases attachment of endospores of Pasteuria penetrans to the infective juveniles and reduces fecundity : Mucin-like gene from M. incognita
Mucins are highly glycosylated polypeptides involved in many host parasite interactions, but their function in plant-parasitic nematodes is still unknown. In this study, a mucin-like gene was cloned from M. incognita (Mi-muc-1, 1125 bp) and characterized. Analysis revealed that the Mi-MUC-1 was composed of α-helix and contained two predicted mitogen-activated protein kinase (MAPK) phosphorylation sites. The protein was found to have high O-glycosylation sites in the sequence. Quantitative PCR (qPCR) showed the highest expression in the adult female and in situ hybridization revealed the localization of Mi-muc-1 mRNA expression around the phasmid, located in tail of the worm body. Knockdown of Mi-muc-1 showed a significant decrease in attachment of P. penetrans' endospores and also human red blood cells suggesting Mi-MUC-1 is a glycoprotein present on the surface coat of infective juveniles and involved in immunity. Further characterization using endospore bioassays by pretreating the infective juveniles with different carbohydrates suggested that D-glucose, D-galactose and D-xylose were involved as ligands for attachment. Lastly, the long term effect of RNAi mediated knockdown of Mi-muc-1 led to significant reduction in the nematode fecundity.