Table_1_Genome-wide analysis of terpene synthase gene family to explore candidate genes related to disease resistance in Prunus persica.xls

In plants, a family of terpene synthases (TPSs) is responsible for the biosynthesis of terpenes and contributes to species-specific diversity of volatile organic compounds, which play essential roles in fitness of plants. However, little is known about the TPS gene family in peach and/or nectarine (Prunus persica L.). In this study, we identified 40 PpTPS genes in peach genome v2.0. Although these PpTPSs could be clustered into five classes, they distribute in several gene clusters of three chromosomes, share conserved exon-intron organizations, and code similar protein motifs. Thirty-five PpTPSs, especially PpTPS2, PpTPS23, PpTPS17, PpTPS18, and PpTPS19, altered their transcript levels after inoculation with Botryosphaeria dothidea, a cause of peach gummosis, compared to the mock treatments, which might further affect the contents of 133 terpenoids at 48 hours and/or 84 hours post inoculations in the current-year shoots of ‘Huyou018’, a highly susceptible nectarine cultivar. Moreover, about fifteen PpTPSs, such as PpTPS1, PpTPS2, PpTPS3, and PpTPS5, showed distinct expression patterns during fruit development and ripening in two peach cultivars, yellow-fleshed ‘Jinchun’ and white-fleshed ‘Hikawa Hakuho’. Among them, the transcription level of chloroplast-localized PpTPS3 was obviously related to the content of linalool in fruit pulps. In addition, elevated concentrations (0.1 g/L to 1.0 g/L) of linalool showed antifungal activities in PDA medium. These results improve our understanding of peach PpTPS genes and their potential roles in defense responses against pathogens.

在植物中，萜合酶（terpene synthases, TPS）家族负责萜类化合物的生物合成，并促成挥发性有机化合物的物种特异性多样性，这类化合物对植物的适合度具有关键作用。然而，目前对于桃或油桃（Prunus persica L.）中的TPS基因家族的研究仍较为匮乏。本研究在桃基因组v2.0版本中共鉴定出40个PpTPS基因。尽管这些PpTPS可聚类为5个类群，但它们分布于3条染色体的多个基因簇中，且拥有保守的外显子-内含子结构与相似的蛋白质基序。与空白对照处理相比，35个PpTPS基因（尤其是PpTPS2、PpTPS23、PpTPS17、PpTPS18与PpTPS19）在接种桃流胶病病原菌葡萄座腔菌（Botryosphaeria dothidea）后，其转录水平发生显著变化；该变化可能进一步影响高感油桃品种‘沪油018’当年生枝条在接种后48小时和/或84小时时的133种萜类化合物含量。此外，在黄肉桃品种‘金纯’与白肉桃品种‘Hikawa Hakuho’的果实发育及成熟过程中，约15个PpTPS基因（如PpTPS1、PpTPS2、PpTPS3与PpTPS5）呈现出显著差异的表达模式。其中，定位于叶绿体的PpTPS3的转录水平与果肉中芳樟醇（linalool）的含量显著相关。此外，浓度为0.1 g/L至1.0 g/L的芳樟醇（linalool）在马铃薯葡萄糖琼脂（Potato Dextrose Agar, PDA）培养基中表现出抗真菌活性。上述研究结果加深了我们对桃PpTPS基因及其在抵御病原菌的防御反应中潜在作用的认知。