College of Horticulture, Sichuan Agricultural University, Chengdu 611130, China.
Institute of Pomology and Olericulture, Sichuan Agricultural University, Chengdu 611130, China.
Int J Mol Sci. 2022 May 13;23(10):5457. doi: 10.3390/ijms23105457.
Tangor, an important citrus type, is a hybrid of orange and mandarin and possesses their advantageous characteristics. Fruit quality is an important factor limiting the development of the citrus industry and highly depends on fruit development and ripening programs. However, fruit development and quality formation have not been completely explored in mandarin-orange hybrids. We sequenced the metabolome and transcriptome of three mandarin-orange hybrid cultivars at the early fruiting [90 days after full bloom (DAFB)], color change (180 DAFB), and ripening (270 DAFB) stages. Metabolome sequencing was performed to preliminarily identify the accumulation patterns of primary and secondary metabolites related to fruit quality and hormones regulating fruit development. Transcriptome analysis showed that many genes related to primary metabolism, secondary metabolism, cell wall metabolism, phytohormones, and transcriptional regulation were up-regulated in all three cultivars during fruit development and ripening. Additionally, multiple key genes were identified that may play a role in sucrose, citric acid and flavonoid accumulation, cell wall modification, and abscisic acid signaling, which may provide a valuable resource for future research on enhancement of fruit quality of hybrid citrus. Overall, this study provides new insights into the molecular basis of pulp growth and development regulation and fruit quality formation in mandarin-orange hybrids.
橘柚是一种重要的柑橘类型，是甜橙和宽皮橘的杂种，具有它们的优势特征。果实品质是限制柑橘产业发展的重要因素，高度依赖于果实发育和成熟程序。然而，宽皮橘甜橙杂种果实发育和品质形成的机制尚未完全阐明。我们对三个宽皮橘甜橙杂种品种在幼果期（盛花后 90 天（DAFB））、转色期（180 DAFB）和成熟期（270 DAFB）三个时期进行了代谢组和转录组测序。代谢组测序初步鉴定了与果实品质和调节果实发育的激素相关的初级和次级代谢物的积累模式。转录组分析表明，在果实发育和成熟过程中，三个品种中与初级代谢、次级代谢、细胞壁代谢、植物激素和转录调控相关的许多基因都上调。此外，还鉴定到多个可能在蔗糖、柠檬酸和类黄酮积累、细胞壁修饰和脱落酸信号传导中发挥作用的关键基因，这可能为未来提高杂种柑橘果实品质的研究提供有价值的资源。总的来说，本研究为宽皮橘甜橙杂种果肉生长发育调控和果实品质形成的分子基础提供了新的见解。
