Fig. 5

Screening of differentially expressed saponin synthesis genes and transcription factors in E. senticosus under drought stress. A: The expression level of triterpenoid saponin synthase gene; B: The correlation between differentially expressed genes in the synthesis pathway of triterpenoid saponins and terpenoid metabolites; C: Differential expression of transcription factors; D: The correlation between differentially expressed transcription factors and EsFPS, EsSS, and EsSE genes; E: The correlation between differentially expressed transcription factors and the content of triterpenoid saponins. Note: Pmn001705: 3,24-Dihydroxy-17,21-semiacetal-12(13)oleanolic fruit; pmn001706: 2-hydroxyoleanolic acid; Zmpn008194: Corosolic acid; Smpn011792: 2,3-dihydroxy-12-ursen-28-oic acid; Lmzn006169: Pomolic acid; mws1610: Maslinic acid; pmp000444: 27,28-Dicarboxyl ursolic acid; Hmmp006366: Saponin PE; Hmmp006067: Oleanolic acid-3-O-glucosyl(1→2)glucoside; p7074: ciwujianosidesD2; Cmmn012461: Dehydroabietic acid; pmn001505: Oleanolic acid-3-O-xylosyl(1→3)glucuronide; Cmhp005457: HN-saponin F; Zmcn006809: Oleanolic acid-3-O-rha(1–2)-(ara)-28-O-glucoside ester; Hmmp004534: Hederagenin-3-O-glucosyl(1–2) glucosyl(1–4)arabinoside; Zmcn005324: Ciwujianoside C3; MWSslk258: Hederacoside D; Zmcn005492: 3-O-Ara-Oleanolic acid-28-O-glc-glc(-Ac)-rha; Zmcn005640: Ciwujianoside D1; Zmcn004907: 3-O-Ara-rha-Oleanolic acid-28-O-glc-glc-rha-30-Methoxy; and Zmcp005550: hederagenin-3-O-glc-(1–4)[L-rha(1–3)]D-glc(1–3)L-rha(1–2)L-ara. Cluster-21888.72024 and Cluster-21888.81111: EsFPS; Cluster-21888.146350, Cluster-21888.128868, Cluster-21888.97206, Cluster-21888.104112, and Cluster-21888.69845: EsSS; Cluster-21888.128179, Cluster-21888.214970, and Cluster-21888.77261: EsSE