Defense reaction to stem rot in a cultivated peanut

Stem rot, caused by the fungus Athelia rolfsii, severely reduces peanut yields, yet the molecular basis of peanut defense against this pathogen remains poorly defined. Here, we investigated defense responses in two Arachis hypogaea cultivars Qicai(susceptibility) and Silihong(resistance) following infection with A. rolfsii GY using RNA-seq and complementary physiological analyses. At 72 h post-inoculation, transcriptome profiling identified 406 and 7022 DEGs respectively, with 196 common DEGs. In Qicai, DEGs were mainly enriched in the photosynthesis-antenna proteins, DNA replication, phenylpropanoid biosynthesis, and photosynthesis. Whereas DEGs of Silihong were significantly involved into flavonoid biosynthesis, glutathione metabolism, phenylpropanoid biosynthesis, and the MAPK signaling pathway motor protein activity, cutin/suberin/wax biosynthesis, and photosynthesis-antenna proteins. Together, these results demonstrated that Qicai and Silihong all activated multiple defense pathways upon A. rolfsii challenge, while Silihong showed a more sensitive defensive response than Qicai. This study will provide a comprehensive understanding of the molecular factors involved in peanut responses to A. rolfsii infection, offering valuable insights for breeding stem-rot-resistant cultivars.