PGC and infection: In response to biochar and infection by R. solani, transcripts involved in the TCA cycle (FDH, MLS, and PEPC), amino acid metabolism (AGT, ASN, DPSC2, G5K, and PAL1) and glutathione metabolism (GST) were down-regulated as early as 6 h.p.i., with fold changes ranging from −3.85 to −1.54 (Supplementary Table S1).