Cross-talk interactions of exogenous nitric oxide and sucrose modulates phenylpropanoid metabolism in yellow lupine embryo axes infected with Fusarium oxysporum

Abstract

The aim of the study was to examine cross-talk of exogenous nitric oxide (NO) and sucrose in the mechanisms of synthesis and accumulation of isoflavonoids in embryo axes of Lupinus luteus L. cv. Juno. It was verified whether the interaction of these molecules can modulate the defense response of axes to infection and development of the pathogenic fungus Fusarium oxysporum f. sp. lupini. Sucrose alone strongly stimulated a high level of genistein glucoside in axes pretreated with exogenous nitric oxide (SNP or GSNO) and non-pretreated axes. As a result of amplification of the signal coming from sucrose and GSNO, high isoflavonoids accumulation was observed (+Sn+GSNO). It needs to be stressed that infection in tissues pretreated with SNP/GSNO and cultured on the medium with sucrose (+Si+SNP/+Si+GSNO) very strongly enhances the accumulation of free isoflavone aglycones. In +Si+SNP axes phenylalanine ammonia-lyase activity was high up to 72h. As early as at 12h in +Si+SNP axes an increase was recorded in gene expression level of the specific isoflavonoid synthesis pathway. At 24h in +Si+SNP axes a very high total antioxidant capacity dependent on the pool of fast antioxidants was noted. Post-infection generation of semiquinone radicals was lower in axes with a high level of sucrose than with a deficit.

Keywords: +Si+SNP/GSNO; +Si−SNP/GSNO; +Sn+SNP/GSNO; +Sn−SNP/GSNO; 0i+SNP/GSNO; 0i−SNP/GSNO; 0n+SNP/GSNO; 0n−SNP/GSNO; CHI; CHS; EPR; Fusarium oxysporum; GSNO; IFS; Isoflavonoids; Lupinus luteus; NO synthase; NOS; Nitric oxide; PAL; RNS; S-nitrosoglutathione; SNP; Semiquinone radicals; Sucrose; TAC; cADPR; chalcone isomerase; chalcone synthase; cyclic ADP ribose; electron paramagnetic resonance; isoflavone synthase; not pretreated with SNP/GSNO and inoculated with F. oxysporum before being transferred to the medium; not pretreated with SNP/GSNO and not inoculated before being transferred to the medium; not pretreated with SNP/GSNO, inoculated and cultured with sucrose; not pretreated with SNP/GSNO, inoculated and cultured without sucrose; not pretreated with SNP/GSNO, not inoculated and cultured with sucrose; not pretreated with SNP/GSNO, not inoculated and cultured without sucrose; phenylalanine ammonia-lyase; pretreated with SNP/GSNO and inoculated with F. oxysporum before being transferred to the medium; pretreated with SNP/GSNO and not inoculated before being transferred to the medium; pretreated with SNP/GSNO, inoculated and cultured with sucrose; pretreated with SNP/GSNO, inoculated and cultured without sucrose; pretreated with SNP/GSNO, not inoculated and cultured with sucrose; pretreated with SNP/GSNO, not inoculated and cultured without sucrose; reactive nitrogen species; sodium nitroprusside; total antioxidant capacity; −Si+SNP/GSNO; −Si−SNP; −Sn+SNP/GSNO; −Sn−SNP/GSNO.