Liang Dong, Zhu Tingting, Ni Zhiyou, Lin Lijin, Tang Yi, Wang Zhihui, Wang Xun, Wang Jin, Lv Xiulan, Xia Hui
Institute of Pomology and Olericulture, Sichuan Agricultural University, Chengdu, Sichuan, China.
College of Horticulture, Sichuan Agricultural University, Chengdu, Sichuan, China.
PLoS One. 2017 Feb 28;12(2):e0172818. doi: 10.1371/journal.pone.0172818. eCollection 2017.
To elucidate metabolism of ascorbic acid (AsA) in sweet cherry fruit (Prunus avium 'Hongdeng'), we quantified AsA concentration, cloned sequences involved in AsA metabolism and investigated their mRNA expression levels, and determined the activity levels of selected enzymes during fruit development and maturation. We found that AsA concentration was highest at the petal-fall period (0 days after anthesis) and decreased progressively during ripening, but with a slight increase at maturity. AsA did nevertheless continue to accumulate over time because of the increase in fruit fresh weight. Full-length cDNAs of 10 genes involved in the L-galactose pathway of AsA biosynthesis and 10 involved in recycling were obtained. Gene expression patterns of GDP-L-galactose phosphorylase (GGP2), L-galactono-1, 4-lactone dehydrogenase (GalLDH), ascorbate peroxidase (APX3), ascorbate oxidase (AO2), glutathione reductase (GR1), and dehydroascorbate reductase (DHAR1) were in accordance with the AsA concentration pattern during fruit development, indicating that genes involved in ascorbic acid biosynthesis, degradation, and recycling worked in concert to regulate ascorbic acid accumulation in sweet cherry fruit.
为阐明甜樱桃(Prunus avium 'Hongdeng')果实中抗坏血酸(AsA)的代谢情况,我们对AsA浓度进行了定量分析,克隆了参与AsA代谢的序列并研究了它们的mRNA表达水平,还测定了果实发育和成熟过程中所选酶的活性水平。我们发现,AsA浓度在落花期(开花后0天)最高,在成熟过程中逐渐降低,但在成熟时略有增加。不过,由于果实鲜重增加,AsA仍随时间持续积累。获得了10个参与AsA生物合成L-半乳糖途径的基因和10个参与循环利用的基因的全长cDNA。GDP-L-半乳糖磷酸化酶(GGP2)、L-半乳糖-1,4-内酯脱氢酶(GalLDH)、抗坏血酸过氧化物酶(APX3)、抗坏血酸氧化酶(AO2)、谷胱甘肽还原酶(GR1)和脱氢抗坏血酸还原酶(DHAR1)的基因表达模式与果实发育过程中的AsA浓度模式一致,表明参与抗坏血酸生物合成、降解和循环利用的基因协同作用,调节甜樱桃果实中抗坏血酸的积累。