Trehalose Regulates Starch, Sorbitol, and Energy Metabolism to Enhance Tolerance to Blue Mold of “Golden Delicious” Apple Fruit

Abstract

The efficacy of trehalose on the lesion diameter of apples (cv. Golden Delicious) inoculated with Penicillium expansum was evaluated to screen the optimal concentration. The changes in gene expression and activity of the enzyme in starch, sorbitol, and energy metabolism were also investigated in apples after trehalose treatment. The results revealed that trehalose dipping reduced the lesion diameter of apples inoculated with P. expansum. Trehalose suppressed the activities and gene expressions of β-amylase, NAD-sorbitol dehydrogenase, and NADP-sorbitol dehydrogenase, whereas it decreased the sorbitol 6-phosphate dehydrogenase gene expression and amylose, amylopectin, total starch, and reducing sugar contents. Additionally, trehalose improved the gene expressions and activities of α-amylase, starch-branching enzymes, total amylase, H+-ATPase, and Ca2+-ATPase, as well as soluble sugar, adenosine triphosphate, and adenosine diphosphate contents and energy charge in apples. These findings imply that trehalose could induce tolerance to the blue mold of apple fruit by regulating starch, sorbitol, and energy metabolism.

l‐Glutamate maintains the quality of apple fruit by mediating carotenoid, sorbitol and sucrose metabolisms

“…Evaporation and respiration metabolism are the main factors of mass loss. This study indicated that l ‐glutamate treatment effectively suppressed mass loss of apples during the 15 days of storage, which was consistent with the previous reports in apples treated with trehalose and ATP 7,18 . Apple is a kind of climacteric fruit, the higher respiratory rate and ethylene release accelerate senescence and quality deterioration.…”

“…This study indicated that L-glutamate treatment effectively suppressed mass loss of apples during the 15 days of storage, which was consistent with the previous reports in apples treated with trehalose and ATP. 7,18 Apple is a kind of climacteric fruit, the higher respiratory rate and ethylene release accelerate senescence and quality deterioration. Study has proven that inhibition of respiration and ethylene release can suppress fruit ripening and senescence.…”

“…Variation of L *, a * and b * values at the same position of the fruit on days 0, 3, 6, 9, 12 and 15 were measured by a CR‐400 chromometer. Mass loss of the fruit was determined between days 0–15 with 2‐day intervals and expressed as percentage according to the approach of Ge et al 18 . Ethylene release and respiratory rate were analyzed by a gas chromatograph (GC‐7820, China) following the procedures describer by Li et al 3 .…”

“…Sucrose metabolism plays an important role in enhancing defense responses of horticultural products to abiotic and biological stresses, regulating the expression of transcription factors and specific genes 17 . Studies have proven that postharvest trehalose, 18 melatonin, 19 ATP, 7 sodium nitroprusside 5 and acibenzolar‐S‐methyl (ASM) 20 treatment maintain the quality of apples by altering respiratory and sucrose metabolisms. As a primary photosynthetic product of Rosaceae plants, sorbitol is formed from glucose‐6‐phosphate that catalyzed by sorbitol‐6‐phosphate phosphatase and aldose‐6‐phosphate reductase in the cytosol of source leaves 18 .…”

“…Studies have proven that postharvest trehalose, 18 melatonin, 19 ATP, 7 sodium nitroprusside 5 and acibenzolar‐S‐methyl (ASM) 20 treatment maintain the quality of apples by altering respiratory and sucrose metabolisms. As a primary photosynthetic product of Rosaceae plants, sorbitol is formed from glucose‐6‐phosphate that catalyzed by sorbitol‐6‐phosphate phosphatase and aldose‐6‐phosphate reductase in the cytosol of source leaves 18 . Sorbitol metabolism in fruit is related to sorbitol oxidase (SOX) and sorbitol dehydrogenase (SDH).…”