Involvement of brassinosteroids and ethylene in the control of mitochondrial electron transport chain in postharvest papaya fruit

Abstract

The plant hormones brassinosteroids (BR) and ethylene (ET) act together to regulate plant metabolism. We used BR and 1-methylcyclopropene (1-MCP, an ET action inhibitor) to elucidate the interactions between both hormones for the regulation of mitochondrial respiratory pathways in papaya fruit. The exogenous application of the 24-epibrassinolide (epiBR) enhanced the alternative oxidase (AOX) capacity. While treatment with Brz2001 (Brz is a specific inhibitor of the BR synthesis) also enhanced AOX capacity, these effects lacked in fruit treated simultaneously with epiBR and Brz. Changing the BR level had no effect on ET emission rate in the first 24 h, but a reduction in ET emission was observed in Brz-treated fruit on the fifth day. Together with Brz, epiBR increased the ET production on the fifth day, following the day in which the treatment was carried out. When the ET sensitivity of fruit was inhibited by the application of 1-MCP, the effects of epiBR and Brz were opposite to those obtained without 1-MCP. AOX capacity was slightly inhibited by epiBR in fruit pre-treated with 1-MCP. Data suggest that BR and ET act antagonistically, therefore regulating, directly or indirectly, AOX capacity during papaya fruit ripening.

Effects of brassinosteroids on quality attributes and ethylene synthesis in postharvest tomato fruit

“…ACS and ACO, two key enzymes, regulated ethylene production during ripening. In particular, LeACS2, LeACS4, LeACO1, and LeACO4, members of the ACS and ACO families, are responsible for the massive ethylene production during fruit ripening in tomatoes (Barry et al, 2000;Klee and Giovannoni, 2011;Mazorra et al, 2013). In our study, expression analyses of ethylene synthesis genes such as LeACS2, LeACS4, LeACO1 and LeACO4 revealed ACS and ACO transcript levels were significantly increased in brassinolidetreated fruit while reduced in brassinazole-treated fruit (Fig.…”

Vacuum Infiltration of 24-Epibrassinolide Delays Chlorophyll Degradation and Maintains Quality of Lime During Cold Storage

“…Gao et al [2016] also reported that peach fruit firmness was about 53% higher in treatment with EBR than that in control fruit at the end of storage. However, Mazorra et al [2013] were not able to detect consistent differences in papaya firmness among BRs treatments. BRs decreased activity of enzymes that have role in firmness such as polygalacturonase, pectin methylesterase and etc.…”

1-Methylcyclopropene alleviates chilling injury by regulating energy metabolism and fatty acid content in ‘Nanguo’ pears

“…Respiratory activity was determined as described previously (Mazorra et al, 2013). Briefly, 1 mg of protein was used to determine the respiratory activity of mitochondria by using an oxygen electrode (Hansatech, Respire 1, UK) in 1.0 mL reaction medium [0.35 M mannitol, 10 mM phosphate buffer, 10 mM KCl, 5 mM MgCl 2 , 0.5% (w/v) BSA, pH 7.2] at 25 C. The entire assay was performed in the presence of 200 mM glutamate as the substrate for respiration.…”