Genome-Wide Association Study of Cell Wall Traits and Digestibility in Switchgrass Diversity Panel

Biomass degradation of switchgrass (Panicum virgatum L.) for bioethanol production is inhibited by lignin and other hydroxycinnamates in secondary cell walls. Thus, understanding the genetic control of cell wall components and digestibility can facilitate improvement of switchgrass as a bioenergy crop. Our study deployed single nucleotide polymorphisms (SNPs) discovered using genome-wide exome-capture sequencing to conduct an association analysis on six cell wall and digestibility traits. Pathway analysis was conducted to decipher the metabolic pathways associated with cell wall traits in switchgrass. In total, 86 genes were significantly associated with the six traits, out of which 33 genes were highlighted based on functions of their homologs in other species in relation to plant cell development. Significant pathways were classified into functional groups including phenylpropanoid biosynthesis, signal transduction, circadian rhythm and other metabolic pathways. The genomic regions that contain these genes can be used to facilitate genomic selection for biomass quality in switchgrass.