Meeting Abstract
Plant symbiosis with nitrogen-fixing cyanobacteria is a unique form of mutualistic association that has independently evolved in diverse lineages including a few species of bryophytes, ferns, cycads, and one small genus of flowering plants. Compared to other nitrogen-fixing microbes, cyanobacteria are generally less dependent on the plant host, and therefore could be an ideal partner for engineering symbiotic nitrogen fixation into crop plants. However, our current understanding of plant-cyanobacteria symbioses is rudimentary. The phylogenetic diversity of cyanobionts has been largely unexplored, and the plant genes involved in cyanobacterial symbiosis have remained unknown. Here I will present our ongoing work on cyanobacterial symbioses in ferns (Azolla) and hornworts. Using Illumina resequencing and PacBio amplicon-seq, we are beginning to characterize the cyanobiont diversity and examine plant-cyanobiont co-evolutionary history. In addition, several putative symbiosis genes have been identified through our comparative genomics and RNA-seq analyses.
