Bosman Robin Nicole, Vervalle Jessica Anne-Marie, November Danielle Lisa, Burger Phyllis, Lashbrooke Justin Graham
South African Grape and Wine Research Institute, Stellenbosch University, Stellenbosch, South Africa.
Laboratory of Nematology, Department of Plant Sciences, Wageningen University, Wageningen, Netherlands.
Front Plant Sci. 2023 Mar 16;14:1112214. doi: 10.3389/fpls.2023.1112214. eCollection 2023.
Volatile organic compounds such as terpenes influence the quality parameters of grapevine through their contribution to the flavour and aroma profile of berries. Biosynthesis of volatile organic compounds in grapevine is relatively complex and controlled by multiple genes, the majority of which are unknown or uncharacterised. To identify the genomic regions that associate with modulation of these compounds in grapevine berries, volatile metabolic data generated GC-MS from a grapevine mapping population was used to identify quantitative trait loci (QTLs). Several significant QTLs were associated with terpenes, and candidate genes were proposed for sesquiterpene and monoterpene biosynthesis. For monoterpenes, loci on chromosomes 12 and 13 were shown to be associated with geraniol and cyclic monoterpene accumulation, respectively. The locus on chromosome 12 was shown to contain a geraniol synthase gene (), while the locus on chromosome 13 contained an α-terpineol synthase gene (). Molecular and genomic investigation of and revealed that these genes were found in tandemly duplicated clusters, displaying high levels of hemizygosity. Gene copy number analysis further showed that not only did and copy numbers vary within the mapping population, but also across recently sequenced cultivars. Significantly, copy number correlated with both gene expression and cyclic monoterpene accumulation in the mapping population. A hypothesis for a hyper-functional allele linked to increased gene copy number in the mapping population is presented and can potentially lead to selection of cultivars with modulated terpene profiles. The study highlights the impact of gene duplication and copy number variation on terpene accumulation in grapevine.
诸如萜类化合物之类的挥发性有机化合物通过对葡萄浆果的风味和香气特征的贡献来影响葡萄的品质参数。葡萄中挥发性有机化合物的生物合成相对复杂，受多个基因控制，其中大多数基因未知或未被表征。为了确定与葡萄浆果中这些化合物调控相关的基因组区域，利用气相色谱 - 质谱联用（GC-MS）从葡萄作图群体中生成的挥发性代谢数据来鉴定数量性状位点（QTL）。几个显著的QTL与萜类化合物相关，并提出了倍半萜和单萜生物合成的候选基因。对于单萜，12号和13号染色体上的位点分别显示与香叶醇和环状单萜积累相关。12号染色体上的位点显示含有一个香叶醇合酶基因（），而13号染色体上的位点含有一个α-松油醇合酶基因（）。对和的分子和基因组研究表明，这些基因存在于串联重复的簇中，表现出高水平的半合子性。基因拷贝数分析进一步表明，不仅和的拷贝数在作图群体中有所不同，而且在最近测序的品种中也存在差异。值得注意的是，在作图群体中，拷贝数与基因表达和环状单萜积累均相关。本文提出了一个关于在作图群体中与增加的基因拷贝数相关的超功能等位基因的假设，这可能会导致对具有调控萜类化合物谱的品种的选择。该研究突出了基因复制和拷贝数变异对葡萄中萜类化合物积累的影响。
