Upadhyay Anuradha, Maske Smita, Jogaiah Satisha, Kadoo Narendra Y, Gupta Vidya S
ICAR-National Research Centre for Grapes, Solapur Road, Pune, Maharashtra, 412307, India.
ICAR-Indian Institute of Horticulture Research, Bengaluru, Karnataka, India.
Funct Integr Genomics. 2018 Jul;18(4):439-455. doi: 10.1007/s10142-018-0605-0. Epub 2018 Apr 6.
In grapes (Vitis vinifera L.), exogenous gibberellic acid (GA) is applied at different stages of bunch development to achieve desirable bunch shape and berry size in seedless grapes used for table purpose. RNA sequence-based transcriptome analysis was used to understand the mechanism of GA action at cluster emergence, full bloom, and berry stage in table grape variety Thompson Seedless. At cluster emergence, rachis samples were collected at 6 and 24 h after application of GA, whereas flower clusters and berry samples were collected at 6, 24, and 48 h after application at full bloom and 3-4 mm berry stages. Seven hundred thirty-three genes were differentially expressed in GA-treated samples. At rachis and flower cluster stage respectively, 126 and 264 genes were found to be significantly differentially expressed within 6 h of GA application. The number of DEG reduced considerably at 24 h. However, at berry stage, major changes occurred even at 24 h and a number of DEGs at 6 and 24 h were 174 and 191, respectively. As compared to upregulated genes, larger numbers of genes were downregulated. Stage-specific response to the GA application was observed as evident from the unique set of DEGs at each stage and only a few common genes among three stages. Among the DEGs, 67 were transcription factors. Functional categorization and enrichment analysis revealed that several transcripts involved in sucrose and hexose metabolism, hormone and secondary metabolism, and abiotic and biotic stimuli were enriched in response to application of GA. A high correlation was recorded for real-time PCR and transcriptome data for selected DEGs, thus indicating the robustness of transcriptome data obtained in this study for understanding the GA response at different stages of berry development in grape. Chromosomal localization of DEGs and identification of polymorphic microsatellite markers in selected genes have potential for their use in breeding for varieties with improved bunch architecture.
在葡萄（欧亚种葡萄）中，在果穗发育的不同阶段施用外源赤霉素（GA），以在用于鲜食的无核葡萄中获得理想的果穗形状和浆果大小。基于RNA序列的转录组分析被用于了解鲜食葡萄品种汤普森无核在果穗出现期、盛花期和浆果期GA作用的机制。在果穗出现期，在施用GA后6小时和24小时采集穗轴样本，而在盛花期和浆果直径3 - 4毫米期施用GA后6小时、24小时和48小时采集花穗和浆果样本。在GA处理的样本中有733个基因差异表达。在穗轴和花穗期，分别在施用GA后6小时发现126个和264个基因显著差异表达。在24小时时差异表达基因的数量大幅减少。然而，在浆果期，即使在24小时也发生了主要变化，在6小时和24小时差异表达基因的数量分别为174个和191个。与上调基因相比，下调基因的数量更多。从每个阶段独特的差异表达基因集以及三个阶段中只有少数共同基因可以明显看出，对GA施用存在阶段特异性反应。在差异表达基因中，有67个是转录因子。功能分类和富集分析表明，响应GA施用，一些参与蔗糖和己糖代谢、激素和次生代谢以及非生物和生物刺激的转录本被富集。对选定差异表达基因的实时PCR和转录组数据记录了高度相关性，从而表明本研究中获得的转录组数据对于理解葡萄浆果发育不同阶段的GA反应具有可靠性。差异表达基因的染色体定位以及选定基因中多态微卫星标记的鉴定在培育具有改良果穗结构的品种方面具有潜在用途。
