Plant-associated microbial communities play an essential role in determining the phenotypic output of their hosts. Some of these bacteria and fungi confer benefit to crop species through increasing nutrient and resource uptake efficiency, out-competing plant pathogens, and improving abiotic stress response. Despite much research, only a tiny fraction of plant microbiomes have been uncovered and evaluated, and many of the rules governing microbial community recruitment to the host microbiome remain unknown. This project will address three major questions. 1) What are the general and species-specific plant microbiome responses to abiotic stress across the grasses? Recent work in other plant systems has demonstrated that host genetics can play a role in selecting for specific microbial communities, but the extent to which the plant microbiome differs under abiotic stress between diverse grass species grown within the same soil has yet to be explored. 2) When and how do plant microbiomes respond to drought? The proposed work will uncover temporal changes in bacterial community structure in Sorghum bicolor as it acclimates to and recovers from drought, identifying key community members that increase and decrease in abundance during environmental stress. 3) How does species-species interaction within microbial communities affect relative root colonization efficiency under drought, and to what extent do root endophytes of sorghum effectively colonize other grass species? A novel high-throughput pooling strategy will be used to screen strains from a microbial library for their relative ability to colonize sorghum and to promote plant growth under drought conditions. As we carry out these studies we are developing novel computational tools to correlate information about the composition of the plant-associated microbial communities with genomic, epigenomic and transcriptional datasets from the host; we use a variety of statistical models to help explain Sorghum's drought response and response to PGPM, and to help us to identify the host genes responsible for these interactions.
The successful candidate will play a role in a variety of experiments. These experiments may involve: 1) phenotyping plants during greenhouse- or field-based drought stress trials; 2) unraveling the plant-microbe interactions through experiments conducted in plant growth chambers; 3) preparation of next generation sequencing libraries. Students will learn standard molecular biology techniques, gain exposure to next-generation sequencing technologies, and hopefully develop a broad understanding of plant and microbial genetics and genomics.
A desire to learn is essential and a love of plants helps a great deal. Students who are highly motivated and able to take on responsibility will be given more and more independence. We are happy to teach students everything they need to do the project as long as they are willing to make a serious commitment.