EAPSI: Elucidating the Role of SYP132A during Arbuscular Mycorrhizal Symbiosis in Oryza Sativa

Stonoha Christina, Fairfield CT

Investigators

Abstract

Plants often recruit soil microbes in order to enhance nutrient availability and absorption by an assortment of mechanisms. Nitrogen-fixing (NF) symbiosis and arbuscular mycorrhizal (AM) symbiosis are two important examples. NF symbiosis has major growth effects on the crops that can form this relationship such as soybean, common bean, pea, peanuts, alfalfa, etc., while AM symbiosis can do the same for many crops that form this symbiosis such as maize and rice. Rice (Oryza sativa), specifically, can have a significant grain yield increase when inoculated with mycorrhizal fungi because of the enhanced nutrient uptake. This can be especially important in parts of the world that rely on this particular crop for the majority of its calories. This award supports research to investigate the role of the SYP132A gene in rice (Oryza sativa) by defining the mycorrhizal phenotype of rice SYP132A mutants.The research could ultimately shed light on a fundamental process in rice (AM symbiosis) that has the potential to greatly increase yield if optimized. The research will be conducted in collaboration with Dr. Ertao Wang, an expert in AM symbiosis in rice, at the Institute of Plant Physiology and Ecology in Shanghai, China. The nitrogen-fixing (NF) symbiotic pathway in plants evolved from the arbuscular mycorrhizal (AM) symbiotic pathway, and therefore the molecular mechanisms share many common elements. Protein trafficking from the plant to the bacteria during NF symbiosis has been shown to be indispensable, but protein trafficking during AM symbiosis is most likely important as well. For this proposed project, I will study the role of a syntaxin gene (SYP132A) in mycorrhizal symbiosis. This gene was previously identified to have a role in NF symbiosis in M. truncatula, namely, it specifically marks the membrane surrounding the intracellular bacteria for targeted protein delivery. I will investigate the function of SYP132A by characterizing the mycorrhizal phenotype of rice T-DNA mutant lines. My hypothesis is that this protein marks the membrane that separates host from the fungus within plant cells. This study will provide evidence that the function of SYP132A is universal and spans multiple host and microbial species. This NSF EAPSI award supports the research of a U.S. graduate student and is funded in collaboration with the Chinese Ministry of Science and Technology.