Wound and defense induced cell wall phenylpropanoids in sweet sorghums with differing responses to stalk pathogens

Authors: KHASIN, MAYA - Former ARS Employee; O`Neill, Patrick; Bernhardson, Lois; Palmer, Nathan - Nate; Scully, Erin; Sarath, Gautam; Sattler, Scott; Funnell-Harris, Deanna

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/13/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Stalk rots significantly impact biomass yield and sugar quality of sweet sorghums. Two lines differing in responses to two stalk rotting fungi were compared: M81-E was more resistant to Macrophomina phaseolina than Colman, and both lines were susceptible to Fusarium thapsinum. RNA sequencing, metabolite profiling, and defense-related enzyme assays were performed to characterize responses of the lines to the pathogens and wounding (control) at 0, 3, and 13 days after inoculation (DAI). Gene expression analyses demonstrated that the genes encoding monolignol pathway related enzymes were a central part of the transcriptional response to wounding at 3 DAI in both lines, which corresponded to the increased accumulation of soluble and wall-bound hydroxycinnamic acids at 13 DAI. Monolignol biosynthetic genes were coexpressed with the transcriptional factor SbMyb76 in Colman inoculations with both fungi and the wound inoculation. However, this coexpression pattern was only observed in M. phaseolina inoculation of M81-E. Together these data suggest that SbMyb76 may activate defense lignin biosynthesis. In wounded plants, the expression of several pathogenesis-related genes was increased in M81-E relative to Colman. In plants inoculated with both pathogens or wound-inoculated, catalase, laccase and peroxidase activities were increased from 3 DAI to 13 DAI for both lines. Together, these results suggest that components of the wound response of M81-E may provide a protective effect against M. phaseolina.