单穗不同留果量对‘阳光玫瑰’葡萄果实品质及香气物质积累的影响

Effect of different fruit loads per cluster on fruit quality and aroma accumulation in‘Shine Muscat’grape

[目的]本文旨在研究单穗不同留果量对‘阳光玫瑰’葡萄果实品质、香气物质及相关基因表达的影响。[方法]以葡萄品种‘阳光玫瑰’为材料,花后1周进行疏果处理,单穗留果量分别为40粒(L40)、60粒(L60)、80粒(L80)。应用GC-MS定量定性分析不同发育阶段葡萄果实中香气成分及含量的变化,并应用qRT-PCR技术研究不同发育阶段果实香气合成相关基因的表达水平。[结果]不同留果量处理对葡萄果实外观品质影响明显,L40处理穗形美观、果粒饱满、色泽均匀;L60处理果粒较小、穗形不紧凑;L80处理果实成熟不一致且杂含大小果。3个处理的果实可溶性固形物含量差异不显著,L40处理的可滴定酸含量显著低于其余处理。在成熟期,C6化合物含量在L60处理果实中较高;而萜烯类物质总含量则在L40处理果实中最高,且单个萜烯物质如芳樟醇、香叶醇等其含量同样明显高于L60和L80处理。另外L40处理较其他处理其果实中各种萜烯物质含量下降更慢,某些萜烯类物质如顺式氧化芳樟醇、香茅醇保留时间更长。果实香气合成相关基因转录分析表明,葡萄醇脱氢酶基因(VvADH)转录表达与果实中醇类物质含量极显著相关。脱氧木酮糖-5-磷酸合成酶基因(VvDXS)转录表达受留果量处理影响明显,且与萜烯物质总量极显著相关。L40处理果实VvDXS表达整体趋势高于其他处理。[结论]单穗留果量为40粒处理有利于葡萄果实发育后期香气物质积累及保存,可明显改善果实外观品质。

[Objectives] This study was conducted to explore the effect of fruit load per cluster on fruit quality,aroma components and relevant gene expression levels in‘Shine Muscat’grape.[Methods] Taking the‘Shine Muscat’as experimental material,berry thinning was conducted to leave 40(L40),60(L60),80(L80)berry numbers per cluster at one week after flowering.The aroma component and contents at different development stages in grape were thoroughly determined by GC-MS,and the expression of relevant genes in the grape at different development stages were determined by qRT-PCR.[Results] The effect of different fruit loads on the appearance of grape fruit was obvious.L40 treatment was superior with graceful shape,full fruit and uniform color;L60 treatment included smaller berries and sparse cluster;L80 treatment reached ripe inconsistency and mixed with different size fruit.The soluble solid contents of L40 treatment were higher,and titrate acid contents were lowest with significant difference.At the maturity stage,C6 compound contents of L60 treatment were higher,but for the total terpene contents,L40 treatment was the highest,and especially for linalool and geraniol.In addition,the terpene compounds of L40 treatment dropped more slowly,and several trace terpenes such as cis-linaloloxide,citronellol disappeared later.The transcriptional analysis of the relative genes revealed that alcoholdehy drogenase gene( VvADH )was mainly responsible for alcohols accumulation.The expression of deoxyxylulose 5-phosphate synthase gene( VvDXS )was significantly affected by the treatment of different fruit loads,and correlated with the total content of terpenes.Overall the expression of VvDXS in L40 treatment was higher than others.[Conclusions] The treatment of 40 berry numbers was conductive to the accumulation and preservation of aroma compounds at the late stage of fruit development,and could significantly improve the appearance quality of the fruit.