Abstract
The parental environment of C. elegans can have lasting effects on progeny development and immunity. Vitamin B12 exposure in C. elegans has been shown to accelerate development and protect against pathogenic bacteria. Here, we show that parental exposure to dietary vitamin B12 or vitamin B12-producing bacteria results in offspring with accelerated growth that persists for a single generation. During infection with the microsporidian Nematocida parisii, the offspring of worms fed vitamin B12 diets have better reproductive fitness but similar infection levels, suggesting increased tolerance to microsporidian infection. Vitamin B12-induced intergenerational growth acceleration and N. parisii tolerance is dependent upon the methionine biosynthesis pathway. Offspring from vitamin B12-exposed parents are protected from pathogenic Pseudomonas vranovensis and this protection is mediated through methionine biosynthesis and propionyl-CoA breakdown pathways. Our results show how parental microbial diet impacts progeny development through the transfer of vitamin B12 which results in accelerated growth and pathogen tolerance.