Arabica coffee SBP transcription factor family members respond to brown leaf spot stress by regulating their expression.

Coffee brown spot is a prevalent foliar fungal disease that seriously threatens the survival and yield of Coffea arabica L. To explore the molecular basis of disease resistance, we conducted a genome-wide identification and analysis of the SBP gene family in C. arabica L. A total of 22 CaSBP genes were identified and classified into three phylogenetic subfamilies, distributed across 12 chromosomes and including nine segmentally duplicated gene pairs. Cis-element analysis revealed a high proportion (55.37%) of hormone-related regulatory elements in CaSBP promoters. Integrated transcriptomic and metabolomic analyses showed that brown spot infection significantly altered the expression of seven CaSBP genes, which was further confirmed by qRT-PCR, accompanied by marked changes in jasmonic acid (JA) and salicylic acid (SA) levels. Functional enrichment analysis indicated that five differentially expressed CaSBP genes were associated with the brassinosteroid (BR) signaling pathway. Together, these results suggest that CaSBP genes may participate in hormone-mediated defense responses during brown spot infection, providing molecular insights for breeding disease-resistant coffee cultivars.