Transcriptome analysis reveals delaying of the ripening and cell-wall degradation of kiwifruit by hydrogen sulfide

BACKGROUND Hydrogen sulfide (H2S) is a known signaling molecule in plants, which has the ability to delay fruit ripening. Our previous studies have shown that H2S treatment could delay the maturation of kiwifruits by inhibiting ethylene production, improving protective enzyme activities, and decreasing the accumulation of reactive oxygen species to protect the cell membrane during storage. The mechanism related to the way in which H2S affected kiwifruit maturation was still unclear. We performed transcriptome sequencing to explore the influences of H2S on the softening of kiwifruit. RESULTS The firmness and the soluble solids content (SSC) of the kiwifruit were significantly better maintained with H2S treatment compared to the control during the storage period (P < 0.05). Transmission electron microscopy (TEM) showed that degradation of the cell wall was inhibited after H2S treatment. Based on transcriptome data analysis and quantitative real-time polymerase chain reaction (qRT-PCR), expression levels of endo-1,4-beta-glucanase (beta-glu), beta-galactosidase (beta-gal) and pectinesterase (PME) decreased whereas pectinesterase inhibitor (PMEI) significantly increased in response to H2S. The members of the signal transduction pathway involved in ethylene were also identified. Hydrogen sulfide inhibited the expression of ethylene receptor 2 (ETR2), ERF003, ERF5, and ERF016, and increased the expression of ethylene-responsive transcription factor 4 (ERF4) and ERF113. CONCLUSION Hydrogen sulfide could delay the ripening and senescence of kiwifruit by regulating the cell-wall degrading enzyme genes and affecting ethylene signal transduction pathway genes. Our results revealed the effect of H2S treatment on the softening of kiwifruit at the transcription level, laying a foundation for further research. (c) 2020 Society of Chemical Industry