Comparing qPCR and CFU to Verify Rhizobia Genotype Proportions

Abstract

Legumes and rhizobia engage in a symbiotic relationship that revolves around the nutrient exchange of rhizobia derived nitrogen for legume synthesized carbon that increases the growth of both partners. Here, we use quantitative polymerase chain reaction (qPCR) and compare our results to a traditional colony forming unit (CFU) method for analyzing rhizobial abundance in more complex populations. First, we confirmed that qPCR yielded similar results to CFU estimation for rhizobial populations within individual nodules and then found that genotypes that fix more nitrogen increased in population proportion over time These experiments demonstrate the utility of qPCR for future experiments interested in analyzing rhizobia genotype proportions and how they relate to the level of benefits legumes receive