Insect stress modulates phenylpropanoid and phytohormone signaling to impair Sorghum defense responses in COMT bmr12 mutant

The Brown midrib 12 (Bmr12) gene in sorghum encodes for Caffeic acid 3-O-methyltransferase (COMT) enzyme producing Syringyl (S) lignin subunits. Loss of function of Bmr12 gene results in plants with reduced S lignin subunits and improved biofuel conversion rate. However, the physiological and molecular consequences of loss of COMT to Fall armyworm infestation (Spodoptera frugiperda), a destructive pest of sorghum, remain unknown. Phenotypic bioassays showed bmr12 to be susceptible to FAW compared to the wild type, RTx430. RNA-seq was performed in wild type (RTx430), bmr12 and Bmr12-OE plants at 0hpi, early (48hpi) and late (10dpi) time points to unravel the source of COMT mediated resistance.