外源GA对夏黑葡萄果梗代谢的影响

Effect of GA on Metabolism of Summer Black Grape Pedicels

利用赤霉素(GA)蘸穗处理葡萄是促进果实膨大的重要途径,研究葡萄膨大期间,外源GA诱导的葡萄果穗花梗器官代谢生理变化,可为科学解释GA处理后花梗与果实的协同发育机制提供依据。以夏黑葡萄为材料,在葡萄盛花期(FFS)分别用15、0 mg/L GA蘸穗处理果实,在处理后的第7天(FFS15-1、FFS0-1)、第20天(FFS15-2、FFS0-2)采样2次;于果实膨大期(FES)在前期的处理基础上再用25 mg/L GA进行第2次处理,并于处理后第7天采样(FES25),采用液相色谱-质谱(LC-MS)检测、鉴定、筛选、注释差异代谢物(SDM)和被富集的代谢途径(MPSE)。结果表明,FFS15-1与FFS0-1相比,出现54种差异代谢物,且上调的SDMs有31种,多具有抗氧化活性,其中,4-coumaric acid参与Phenylpropanoid biosynthesis途径,可加剧木质素的积累;下调的SDMs有23种,主要为氨基酸类,且参与aminoacyl tRNA biosynthesis途径,有利于氮素转运。FFS15-2与FFS0-2相比,上调的SDMs有42种,多与氮素转运、转化有关,表明该时期葡萄对氮素需求强烈。FES25与FFS0-2相比,出现33种SDMs,其中,Indole-3-acrylic acid、Indole-4-carboxaldehyde显著上调,主要起生长调节作用,可能是外源GA处理花梗后的核心代谢产物,直接促进果实膨大和坐果;而FES25与FFS15-2相比,仅产生9个SDM,表明二者间的代谢特征相似,但Trigonelline和(15Z)-9,12,13-Trihydroxy-15-octadecenoic acid显著下调,可缩短细胞周期,加速花梗细胞分裂促进生长。葡萄开花后期至膨大初期,用GA蘸穗处理后,果粒迅速膨大,代谢物Indole-3-acrylic acid、Indole-4-carboxaldehyde运输至果实后有助于提高坐果率,代谢物Trigonelline和(15Z)-9,12,13-Trihydroxy-15-octadecenoic acid显著下调可加速器官发育,这与此期果实膨大需求相一致。

Dipping treatment using gibberellic acid(GA) in grape fruits is an important way to promote fruit enlargement.Study on the metabolic physiological changes of pedicel organs induced by exogenous GA during grape expansion can provide a basis for scientific explanation of the collaborative development mechanism of pedicels and fruits after gibberellic acid treatment.In this study,summer black variety(Vitis vinifera L×Vitis labrusca L) was used as the material.The grapes were treated by dipping with 15 mg/L and 0 mg/L of GA at full flowering stage(FFS),and sampled twice on the 7th days(FFS15-1,FFS0-1)and 20th days(FFS15-2,FFS0-2) after treatment.At the fruit expansion stage(FES),the grapes were treated twice with 25 mg/L of GA on the basis of the previous stage,and then sampled after 7 days(FES25).LC-MS was applied to detect,identify,screen,and note significantly differential metabolites(SDM) and metabolic pathways of significant enrichment(MPSE).The results showed that FFS15-1 exhibited 54 differential metabolites compared to FFS0-1,and there were 31 upregulated SDMs,most of which had antioxidant activity.Among them,4-coumaric acid participated in the phenylpropanoid biosynthesis pathway,which could exacerbate lignin accumulation.There were 23 downregulated SDMs,mainly amino acids,and they participated in the aminoacyl tRNA biosynthesis pathway,which was beneficial for nitrogen transport;compared to FFS0-2,FFS15-2 upregulated 42 SDMs,mostly related to nitrogen transport and transformation,indicating a strong demand for nitrogen in grapes during this period.Compared with FFS0-2,FES25 had 33 SDMs,significantly up-regulated Indole-3-acrylic acid and Indole-4-carboxaldehyde,which played a role in growth regulation and might be the core metabolic product of exogenous GA treatment on pedicels,directly promoting fruit expansion and fruit setting.Compared with FES15-2,FES25 only produced 9SDMs,indicating that the metabolic characteristics between them were similar,and Trigonelline and(15z)-9,12,13-trihydroxy-15-octadecenoic acid were significantly down regulated,which could shorten the cell cycle,accelerate division of pedicel cells,and promote growth.From the late flowering stage to the early stage of grape expansion,after being treated with GA,the fruit rapidly expanded.The transportation of metabolites Indole-3-acrylic acid and Indole-4-carboxylate to the fruit helped to improve fruit setting rate.The significant downregulation of metabolites Trigonelline and(15Z)-9,12,13-Trihydroxy-15-octadecenoic acid could accelerate organ development,which was consistent with the demand for fruit expansion during this period.