Teng Yao, Wang Ye, Zhang Sunjian, Zhang Xiaoying, Li Jiayu, Wu Fengchan, Chen Caixia, Long Xiuqin, Li Anding
Guizhou Academy of Sciences, Guizhou Botanical Garden, Guiyang, China.
Guizhou Academy of Sciences, Institute of Mountain Resources of Guizhou Province, Guiyang, China.
PeerJ. 2024 Sep 11;12:e17983. doi: 10.7717/peerj.17983. eCollection 2024.
Passion fruit () is loved for its delicious flavor and nutritious juice. Although studies have delved into the cultivation and enhancement of passion fruit varieties, the underlying factors contributing to the fruit's appealing aroma remain unclear.
This study analyzed the full-length transcriptomes of two passion fruit cultivars with different flavor profiles: "Tainong 1" (TN1), known for its superior fruit flavor, and "Guihan 1" (GH1), noted for its strong environmental resilience but lackluster taste. Utilizing PacBio Iso-Seq and Illumina RNA-Seq technologies, we discovered terpene synthase (TPS) genes implicated in fruit ripening that may help explain the flavor disparities.
We generated 15,913 isoforms, with N50 lengths of 1,500 and 1,648 bp, and mean lengths of 1,319 and 1,463 bp for TN1 and GH1, respectively. Transcript and isoform lengths ranged from a maximum of 7,779 bp to a minimum of 200 and 209 bp. We identified 14,822 putative coding DNA sequences (CDSs) averaging 1,063 bp, classified 1,007 transcription factors (TFs) into 84 families. Additionally, differential expression analysis of ripening fruit from both cultivars revealed 314 upregulated and 43 downregulated unigenes in TN1 compared to GH1. The top 10 significantly enriched Gene Ontology (GO) terms for the differentially expressed genes (DEGs) indicated that TN1's upregulated genes were primarily involved in nutrient transport, whereas GH1's up-regulated genes were associated with resistance mechanisms. Meanwhile, 17 genes were identified in and 13 of them were members. A comparative analysis when compared with highlighted an expansion of the subfamily in , suggesting a role in its fruit flavor profile.
Our findings explain that the formation of fruit flavor is attributed to the upregulation of essential genes in synthetic pathway, in particular the expansion of subfamily involved in terpenoid synthesis. This finding will also provide a foundational genetic basis for understanding the nuanced flavor differences in this species.
百香果因其美味的风味和营养丰富的果汁而备受喜爱。尽管已有研究深入探讨了百香果品种的栽培和改良，但果实诱人香气形成的潜在因素仍不清楚。
本研究分析了两个风味特征不同的百香果品种的全长转录组：“台农1号”（TN1），以其优异的果实风味而闻名；“桂海1号”（GH1），以其强大的环境适应能力但平淡的口感而著称。利用PacBio Iso-Seq和Illumina RNA-Seq技术，我们发现了与果实成熟相关的萜类合酶（TPS）基因，这可能有助于解释风味差异。
我们分别为TN1和GH1生成了15,913个异构体，N50长度分别为1,500和1,648 bp，平均长度分别为1,319和1,463 bp。转录本和异构体长度范围从最大7,779 bp到最小200和209 bp。我们鉴定出14,822个推定的编码DNA序列（CDS），平均长度为1,063 bp，将1,007个转录因子（TF）分类为84个家族。此外，对两个品种成熟果实的差异表达分析显示，与GH1相比，TN1中有314个上调和43个下调的单基因。差异表达基因（DEG）的前10个显著富集的基因本体（GO）术语表明，TN1上调的基因主要参与营养物质运输，而GH1上调的基因与抗性机制相关。同时，在[具体内容缺失]中鉴定出17个基因，其中13个是[具体内容缺失]成员。与[具体内容缺失]相比的比较分析突出了[具体内容缺失]中[具体内容缺失]亚家族的扩展，表明其在果实风味特征中发挥作用。
我们的研究结果表明，果实风味的形成归因于合成途径中关键基因的上调，特别是参与萜类合成的[具体内容缺失]亚家族的扩展。这一发现也将为理解该物种细微的风味差异提供基础遗传依据。
