Huang Po-Kai, Manganaris George A, Gasic Ksenija, Saski Christopher A, Beckles Diane M, Crisosto Carlos H
Department of Plant Sciences, University of California, Davis, 95616, USA.
Department of Agricultural Sciences, Biotechnology & Food Science, Cyprus University of Technology, Lemesos, 3603, Cyprus.
BMC Plant Biol. 2025 Jul 12;25(1):908. doi: 10.1186/s12870-025-06932-w.
Understanding the molecular mechanisms underlying variations across climacteric categories in tree crops remains challenging, particularly due to the limitations of applying conventional genetic approaches. In this study, we examined genetically related Japanese plum (Prunus salicina Lindl.) cultivars with distinct ethylene production and responses during ripening: 'Santa Rosa' (climacteric fruit), 'Casselman' (suppressed-climacteric fruit), and 'Sweet Miriam' (non-climacteric fruit). Our primary objective was to comprehensively investigate transcriptional differences related to ethylene and fruit softening across three on-tree developmental stages: "Green" (early development), "Mature" (pre-climacteric or early climacteric), and "Ripe" (climacteric). By integrating information from Phytozome and Dicot PLAZA databases, we identified complete gene families for six ethylene-related and seven softening-related genes. Multi-developmental stage RNA-seq clustering revealed that "Late" genes, which increase in expression in ripe fruit, are associated with physiological differences among climacteric categories. We demonstrated that 'Casselman' aligns more closely with 'Sweet Miriam' than 'Santa Rosa' at the transcriptional level for these "Late" genes, consistent with their shared low ethylene production. Gene expression analyses revealed additional factors beyond ethylene, including jasmonate-related genes and NAC transcription factors as influencing climacteric ripening behavior. To extend our findings beyond the three representative cultivars, we performed qPCR on additional cultivars harvested under different field conditions and years, including 'Friar' and 'Fortune' as climacteric plums and 'Late Santa Rosa' and 'Angeleno' as suppressed-climacteric plums. PpACO1, PpPL1, PpBGAL16, PpNAC2, and PpJID1 expression patterns were conserved across cultivars and experimental conditions. Our findings provide novel insights into the transcriptional regulation of climacteric ripening and offer a strategic framework for future genetic studies in plum and other tree crops.
了解木本作物更年期类别间变异的分子机制仍然具有挑战性，特别是由于应用传统遗传方法存在局限性。在本研究中，我们研究了在成熟过程中具有不同乙烯产生和反应的遗传相关日本李（Prunus salicina Lindl.）品种：“圣罗莎”（跃变型果实）、“卡斯尔曼”（抑制跃变型果实）和“甜米里亚姆”（非跃变型果实）。我们的主要目标是全面研究在树上三个发育阶段（“绿色”（早期发育）、“成熟”（跃变前或早期跃变）和“成熟”（跃变））与乙烯和果实软化相关的转录差异。通过整合来自植物基因组数据库（Phytozome）和双子叶植物数据库（Dicot PLAZA）的信息，我们鉴定了六个乙烯相关基因和七个软化相关基因的完整基因家族。多发育阶段RNA测序聚类显示，在成熟果实中表达增加的“晚期”基因与跃变类别间的生理差异相关。我们证明，在这些“晚期”基因的转录水平上，“卡斯尔曼”与“甜米里亚姆”的亲缘关系比与“圣罗莎”更密切，这与其共同的低乙烯产量一致。基因表达分析揭示了乙烯以外的其他因素，包括茉莉酸相关基因和NAC转录因子对跃变成熟行为的影响。为了将我们的研究结果扩展到这三个代表性品种之外，我们对在不同田间条件和年份收获的其他品种进行了qPCR，包括作为跃变型李子的“修士”和“财富”，以及作为抑制跃变型李子的“晚圣罗莎”和“安吉列诺”。PpACO1、PpPL1、PpBGAL16、PpNAC2和PpJID1的表达模式在不同品种和实验条件下是保守的。我们的研究结果为跃变成熟的转录调控提供了新的见解，并为李子和其他木本作物未来的遗传研究提供了一个战略框架。
