Effect of brassinolide on energy status and proline metabolism in postharvest bamboo shoot during chilling stress

• Energy metabolism enzyme activities were enhanced by brassinolide at low temperature.
• Higher resistance of chilling stress was related to levels of ATP and energy charge.
• Brassinolide treatment alleviated chilling injury involved in proline accumulation.

In this study, the effects of brassinolide treatment on chilling injury, energy status and proline metabolism in postharvest bamboo shoots (Phyllostachys praecox f. prevernalis) at 1 °C were investigated. It was shown that chilling injury of bamboo shoots during 42-day storage was effectively reduced by brassinolide treatment at the concentration of 0.5 μM. In terms of energy status, brassinolide treatment significantly inhibited the increase of electrolyte leakage and the accumulation of malondialdehyde. Meanwhile, brassinolide treatment markedly retarded the decline of ATP content and maintained higher energy charge. Enzyme activities of energy metabolism including H+-ATPase, Ca2+-ATPase, succinate dehydrogenase (SDH) and cytochrome C oxidase (CCO) were significantly enhanced by brassinolide treatment. Bamboo shoots treated by brassinolide treatment promoted Δ1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine-δ-aminotransferase (OAT) activity and inhibited proline dehydrogenase (PDH) activity, which elevated proline accumulation. These results suggest that the alleviation in chilling injury by brasinolide may be caused by enhanced enzyme activities related to energy and proline metabolism.

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