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拟南芥AtPDS在番茄中过表达改变果实中类胡萝卜素的富集

已有 304 次阅读 2017-9-14 08:53 |个人分类:每日摘要|系统分类:科研笔记

AtPDS overexpression in tomato: exposing unique patterns of carotenoid self-regulation and an alternative strategy for the enhancement of fruit carotenoid content


First author:Ryan P. McQuinn; Affiliations: Cornell University (康奈尔大学): Ithaca, USA

Corresponding author: James J. Giovannoni


The regulation of plant carotenogenesis (类胡萝卜素合成) is an active research area for both biological discovery and practical implementation (实践应用). In tomato (Solanum lycopersicum; 番茄), we demonstrate additional bottlenecks (瓶颈) exist in the poly-cis-transformation (聚顺变换) of phytoene (八氢番茄红素) to lycopene (番茄红素) in the context of ripening-induced PSY1 expression and activity and reveal phytoene desaturase (PDS; 八氢番茄红素脱氢酶), as a target for manipulation towards elevated lycopene content in maturing tomato fruit. Overexpression of Arabidopsis PDS, AtPDS, elevated PDS transcript abundance in all aerial tissues (地上部分组织) resulting in both altered carotenoid (类胡萝卜素) accumulation and associated pathway gene expression in a tissue-specific manner. Significant increases in downstream carotenoids (all-trans-lycopene and β-carotene) and minimal changes in carotenogenic gene expression (carotenoid isomerase-like 1, CRTIL1; 类胡萝卜素异构酶) suggest overexpression of heterologous (异源) AtPDS in tomato circumvents (绕过; 回避) endogenous regulatory mechanism observed with previous strategies. In transgenic leaves, depletion (用尽) of the PDS substrate, phytoene, was accompanied by minor, but significant increases in xanthophyll (叶黄素) production. Alterations in the leaf carotenogenic transcript profile, including the upstream MEP pathway, were observed revealing unique feedback and feedforward regulatory mechanisms in response to AtPDS overexpression. AtPDS overexpression in the background of the tangerine (carotenoid isomerase, CRTISO) mutant exposes its potential in elevating downstream cis-lycopene accumulation in ripe (成熟的) tomato fruit, as cis-lycopene is more bioavailable (生物可利用的) yet less abundant than all-trans-lycopene in the wild-type control. In summary, we demonstrate the limitation of PDS in ripening fruit, its utility (功用) in modifying carotenoid profiles towards improved quality, and reveal novel carotenoid pathway feedback regulation.


植物类胡萝卜素的调控是一个非常热门的生物研究领域,且具有很高的实践应用价值。在番茄中,我们的研究表明在成熟诱导的PSY1表达和活性背景下在八氢番茄红素向番茄红素聚顺变换存在另外的瓶颈,研究还显示八氢番茄红素脱氢酶PDS是在成熟番茄果实中提升番茄红素含量的目标基因。过表达拟南芥AtPDS基因会促进植物地上部分组织中的PDS转录本积累,并导致类胡萝卜素积累和相关基因表达的组织特异性变化。下游包括顺式番茄红素和β-胡萝卜素的类胡萝卜素含量的显著增加和类胡萝卜素相关基因类胡萝卜素异构酶CRTIL1基因的轻微改变表明在番茄中异源表达AtPDS基因避开了之前研究的一些内源调控机制。在转基因的叶片中,PDS底物八氢番茄红素的耗尽,伴随着叶黄素产物的显著增加,虽然增加幅度较小。叶片中观察到类胡萝卜素相关转录谱的变化,包括上游的MEP通路,这表明响应于过表达AtPDS基因的反馈和前馈机制。在类胡萝卜素异构酶突变体tangerineAtPDS的过表达显示其在成熟番茄果实中潜在的提升下游顺式番茄红素积累的能力,而顺式番茄红素是一个相对于野生型所有顺式番茄红素更具生物效应的,且比野生型中所有顺式番茄红素积累的要少。综上,本文表明了PDS在成熟果实中的限制作用与其在调控类胡萝卜素谱中的功能以提升果实品质,并揭示了类胡萝卜素通路的反馈调节。


通讯James J. Giovannoni (https://plantbio.cals.cornell.edu/people/james-giovannoni)

研究方向:果实成熟的及相关信号转导的分子和遗传分析。1)正常果实发育关键基因的图位克隆;2)基于表达模式和成熟相关信号转导系统确定候选成熟调控及转基因验证;3)功能基因组学工具的开发与利用。


doi: 10.1111/pbi.12789


Journal: Plant Biotechnology Journal
First Published data: September 11, 2017.


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