The endogenous L-cysteine desulfhydrase and hydrogen sulfide participate in supplemented phosphorus-induced tolerance to salinity stress in maize (Zea mays) plants

Abstract

Although phosphorus supplementation (SP) has been shown to improve salinity tolerance in plants, crosstalk betweenhydrogen sulfide (H2S) or L-cysteine desulfhydrase (LDES) and SP-induced salinity tolerance needs to be elucidated. Thus, prior toinitiation of stress treatment, young seedlings were transferred to aqueous solution containing the scavenger of H2S, 0.1 mM hypotaurine(HT), or the inhibitor of LDES, 0.3 mM DL-propargylglycine (PAG), for 12 h. The plants grown under control (no NaCl added) orsalinity stress (SS; 100 mM NaCl) were then supplemented with SP (2.0 mM in total) as KH2PO4 for 5 weeks. SS caused a significantdecrease in plant growth, PSII maximum efficiency, chlorophyll a and b, leaf water potential, relative water content, mineral elementcontents, ascorbate, and glutathione, but a significant increase in hydrogen peroxide, malondialdehyde, electron leakage, proline, theactivities of different key antioxidant enzymes, Na+ contents, endogenous H2S, and LDES activity. The SP-induced tolerance to salinitystress of maize plants was found to be due to reduced leaf Na+ content and oxidative stress, as well as improved antioxidant defencesystem, leaf mineral nutrient contents, plant growth and photosynthetic traits, levels of H2S and proline, and LDES activity. However,HT significantly reversed the levels of H2S, but did not reduce LDES activity. The application of PAG reversed both H2S and LDES inthe salinity-stressed maize plants. Both HT and PAG reversed the positive effects of SP on oxidative stress and the antioxidant defencesystem, suggesting that H2S and LDES both jointly participated in P-induced salinity tolerance of maize plants.