Fernandez Lucie, Le Cunff Loïc, Tello Javier, Lacombe Thierry, Boursiquot Jean Michel, Fournier-Level Alexandre, Bravo Gema, Lalet Sandrine, Torregrosa Laurent, This Patrice, Martinez-Zapater José Miguel
BMC Plant Biol. 2014 Aug 5;14:209. doi: 10.1186/s12870-014-0209-3.
Interaction between TERMINAL FLOWER 1 (TFL1) and LEAFY (LFY) seem to determine the inflorescence architecture in Arabidopsis. In a parallel way, overexpression of VvTFL1A, a grapevine TFL1 homolog, causes delayed flowering and production of a ramose cluster in the reiterated reproductive meristem (RRM) somatic variant of cultivar Carignan. To analyze the possible contribution of this gene to cluster phenotypic variation in a diversity panel of cultivated grapevine (Vitis vinifera L. subsp. vinifera) its nucleotide diversity was characterized and association analyses among detected sequence polymorphisms and phenology and cluster traits was carried out.
A total of 3.6 kb of the VvTFL1A gene, including its promoter, was sequenced in a core collection of 140 individuals designed to maximize phenotypic variation at agronomical relevant traits. Nucleotide variation for VvTFL1A within this collection was higher in the promoter and intron sequences than in the exon regions; where few polymorphisms were located in agreement with a high conservation of coding sequence. Characterization of the VvTFL1A haplotype network identified three major haplogroups, consistent with the geographic origins and the use of the cultivars that could correspond to three major ancestral alleles or evolutionary branches, based on the existence of mutations in linkage disequilibrium. Genetic association studies with cluster traits revealed the presence of major INDEL polymorphisms, explaining 16%, 13% and 25% of flowering time, cluster width and berry weight, respectively, and also structuring the three haplogroups.
At least three major VvTFL1A haplogroups are present in cultivated grapevines, which are defined by the presence of three main polymorphism LD blocks and associated to characteristic phenotypic values for flowering time, cluster width and berry size. Phenotypic differences between haplogroups are consistent with differences observed between Eastern and Western grapevine cultivars and could result from the use of different genetic pools in the domestication process as well as different selection pressures on the development of table and wine cultivars, respectively. Altogether, these results are coherent with previous classifications of grapevine phenotypic diversity mainly based on cluster and berry morphotypes as well as with recent results on the structure of genetic diversity in cultivated grapevine.
拟南芥中TERMINAL FLOWER 1（TFL1）与LEAFY（LFY）之间的相互作用似乎决定了花序结构。同样，葡萄TFL1同源基因VvTFL1A的过表达会导致佳丽酿品种的反复生殖分生组织（RRM）体细胞变体开花延迟，并产生多分支果穗。为了分析该基因对栽培葡萄（欧亚种葡萄亚种）多样性群体中果穗表型变异的可能贡献，对其核苷酸多样性进行了表征，并对检测到的序列多态性与物候和果穗性状进行了关联分析。
在一个由140个个体组成的核心种质中，对包括启动子在内的共3.6 kb的VvTFL1A基因进行了测序，该核心种质旨在使农艺相关性状的表型变异最大化。该群体中VvTFL1A的核苷酸变异在启动子和内含子序列中高于外显子区域；外显子区域中很少有多态性，这与编码序列的高度保守性一致。VvTFL1A单倍型网络的表征确定了三个主要单倍群，基于连锁不平衡中突变的存在，这与品种的地理起源和用途一致，可能对应于三个主要的祖先等位基因或进化分支。与果穗性状的遗传关联研究揭示了主要的插入缺失多态性，分别解释了开花时间、果穗宽度和浆果重量的16%、13%和25%，并且还构建了这三个单倍群。
栽培葡萄中至少存在三个主要的VvTFL1A单倍群，它们由三个主要的多态性连锁不平衡块定义，并与开花时间、果穗宽度和浆果大小的特征表型值相关。单倍群之间的表型差异与东西方葡萄品种之间观察到的差异一致，这可能是由于驯化过程中使用了不同的基因库，以及分别对鲜食和酿酒品种的发育施加了不同的选择压力。总之，这些结果与先前主要基于果穗和浆果形态类型的葡萄表型多样性分类以及栽培葡萄遗传多样性结构的最新结果一致。
