Branched chain amino acids (BCAA) are involved in Heterodera schachtii development on Arabidopsis thaliana

摘要

The plant-parasitic cyst nematode Heterodera schachtii is able to infect Arabidopsis plants and transform root cells in specialised feeding structures called syncytia. These syncytia have strong metabolic sink character and serve as sole nutrient source for nematodes throughout their life. Unlike plants, animals cannot synthesise branched chain amino acids (BCAA) and depend on their diet for them. Thus, being essential amino acids, this study aimed at determining their role in nematode development on Arabidopsis. We found that valine, leucine and isoleucine, among several other amino acids, were enriched in syncytia. Genes coding for threonine synthase and dihydroxyacid dehydratase, common enzymes in BCAA synthesis, were found strongly expressed in syncytia. We use two independent T-DNA insertion mutant alleles of gene coding for dihydroxyacid dehydratase to test its influence on nematode development. Our results showed significant decrease in number of females on mutant plants. Further, the size of cysts and hatching rate of females on mutant plants were also decreased significantly. Mutation did not affect the size of syncytia, revealing that BCAA are important for nematode development but not for syncytium establishment.