Germline mitotic quiescence and programmed cell death are induced inC. elegansby exposure to pathogenicP. aeruginosa

Abstract

AbstractThe impact of exposure to microbial pathogens on animal reproductive capacity and germline physiology is not well understood. The nematodeCaenorhabditis elegansis a bacterivore that encounters pathogenic microbes in its natural environment. How pathogenic bacteria affect host reproductive capacity ofC. elegansis not well understood. Here, we show that exposure ofC. eleganshermaphrodites to the Gram-negative pathogenPseudomonas aeruginosacauses a marked reduction in brood size with concomitant reduction in the number of nuclei in the germline and gonad size. We define two processes that are induced that contribute to the decrease in the number of germ cell nuclei. First, we observe that infection withP. aeruginosaleads to the induction of programmed germ cell death. Second, we observe that this exposure induces mitotic quiescence in the proliferative zone of theC. elegansgonad. Importantly, these processes appear to be reversible; when animals are removed from the presence ofP. aeruginosa, germ cell death is abated, germ cell nuclei numbers increase, and brood sizes recover. The reversible germline dynamics during exposure toP. aeruginosamay represent an adaptive response to improve survival of progeny and may serve to facilitate resource allocation that promotes survival during pathogen infection.