Hydrogen sulfide enhances kiwifruit resistance to soft rot by regulating jasmonic acid signaling pathway.

As the third active gas signal molecule in plants, hydrogen sulfide (H2S) plays important roles in physiological metabolisms and biological process of fruits and vegetables during postharvest storage. In the present study, the effects of H2S on enhancing resistance against soft rot caused by Botryosphaeria dothidea and the involvement of jasmonic acid (JA) signaling pathway in kiwifruit during the storage were investigated. The results showed that 20 µL L-1 H2S fumigation restrained the disease incidence of B. dothidea-inoculated kiwifruit during storage, and delayed the decrease of firmness and the increase of soluble solids (SSC) content. H2S treatment increased the transcription levels of genes related to JA biosynthesis (AcLOX3, AcAOS, AcAOC2, and AcOPR) and signaling pathway (AcCOI1, AcJAZ5, AcMYC2, and AcERF1), as well as the JA accumulation. Meanwhile, H2S promoted the expression of defense-related genes (AcPPO, AcSOD, AcGLU, AcCHI, AcAPX, and AcCAT). Correlation analysis revealed that JA content was positively correlated with the expression levels of JA biosynthesis and defense-related genes. Overall, the results indicated that H2S could promote the increase of endogenous JA content and expression of defense-related genes by regulating the transcription levels of JA pathway-related genes, which contributed to the inhibition on the soft rot occurrence of kiwifruit.

An Antifungal Role of Hydrogen Sulfide on Botryosphaeria Dothidea and Amino Acid Metabolism Involved in Disease Resistance Induced in Postharvest Kiwifruit.

Botryosphaeria dothidea is a major pathogen responsible for postharvest kiwifruit soft rot. This study aimed to determine the influence of hydrogen sulfide (H2S) on postharvest resistance to kiwifruit soft rot and the antifungal role of H2S against B. dothidea. The results indicated that H2S (20 µl L-1) restricted the lesion area following inoculation with B. dothidea. H2S enhanced the production of shikimic acid, tyrosine, tryptophan, and phenylalanine while also increasing the total phenols, flavonoids, and lignin. H2S upregulated the expression of AcDHQS, AcSDH, AcSK, AcPAL, AcCAD, and AcCHS. Additionally, sodium hydrosulfide (NaHS)-released H2S inhibited mycelial growth. NaHS concentrations of 20 and 40 mmol L-1 significantly decreased the mycelial weight and malondialdehyde content (MDA) content while increasing cell membrane conductivity and membrane leakage. The results indicate that H2S induces resistance in kiwifruit via a microbicidal role and amino acid metabolism involved in postharvest kiwifruit disease resistance.