Plasticity of host cell organelles in response to Pb infection

Abstract

AbstractPlasmodiophora brassicae(Pb) is the most important member of the plant pathogenic protist subgroup, Rhizaria.Pbis an obligate soil-borne plant root pathogen which makes the study ofPbbiology and its interaction with its host challenging. To overcome this challenge, we adopted an axenic cell culture method to study the interaction ofPbwith its host plantBrassica spp. at the cellular and molecular levels.Pb, during its life cycle within the host, was confined to the cytoplasm of the infected cells. Our results showed that upon Pb infection, the dynamics of the plant cell organelles including mitochondria, plastids, nuclei, vacuoles, vesicles were altered. Both Plant’s and parasite’sdiacylglycerol acyltransferases(DGAT) genes were highly expressed in the calli, which indicated a need for the oil accumulation at the switch between replication and growth stages of the pathogen. This notion was supported by the accumulation of oil bodies that were only observed inside the pathogen cells. Our results also indicated that starch was utilized by thePbin infected cells, an indication thatPbinduces cell viability by altering the host carbon metabolism. The ongoing dynamic changes in the infected plant cell organelles suggest that plant responds toPbinfection, through the induction of organellar plasticity.