摘要
有机酸是果实主要的品质组分物质之一,直接影响柑橘果实的口感和风味。多数柑橘果实的柠檬酸占总酸含量的70%以上,是主要的有机酸类型。介绍了柑橘果实柠檬酸的代谢途径和国内外柑橘果实柠檬酸研究涉及的果实类型及有机酸特点,综述了参与调控柑橘果实柠檬酸积累的相关基因,指出了柠檬酸合成相关基因CS在不同报道中的功能差异,整理了目前报道的柠檬酸降解相关的Aco、IDH、ACL、GAD、GS基因以及贮藏相关的PH、AHA基因在影响柑橘果实柠檬酸含量中的作用;特别指出了近年来报道的调控柑橘果实柠檬酸积累的相关转录因子研究。柑橘果实柠檬酸积累是一个复杂的过程,受多种因素影响,与其他果实性状研究相比其研究还处于起步阶段。为此,笔者对调控柑橘果实柠檬酸积累的重要基因研究进行了综述,分析了研究现状和存在的不足并展望了今后的研究方向,旨在为柑橘果实柠檬酸代谢研究提供参考。
Organic acid is one of the major components in fruit quality, affecting the flavor of citrus fruit directly. Citrate, accounting for more than 70% of total organic acid, is the dominant acid type in most cit- rus fruits. This paper reviewed the studies on genes involved in citrate accumulation of citrus fruit in past two decades. Citrate is an intermediate of triearboxylic acid (TCA) cycle which is an important pathway supplying power for organism in both plant and animal. In fruit, citrate was believed to derive from two sources. First, fruit biosynthesizes carbohydrates and confers them into citrate by itself through TCA cycle because fruit skin has both chlorophyll and photosynthesis. Second, citrate biosynthesized in roots or leaves was transported into fruit. Both hypothesis had experimental supports in citrus. Previous studies on citrate accumulation included diverse citrus species, containing lemon, sweet orange, navel orange, Satsu- ma mandarin and ponkan. Natural citrate difference between citrus cuhivars was focused firstly as well as some citrus mutants characterizing specific citrate content. Certainly, citrate differences in fruit induced by treatment or by different developing stage were also chosen for investigation. So far, it is commonly ac- cepted that citrate increased sharply in citrus fruit at early developing stage and then decreased constantly in the following stages. The final citrate content in fruit was determined by many factors, but biosynthesis, degradation, utilization and storage metabolism were focused generally. First, the effect of biosynthesis on citrate accumulation. Citrate synthase (CS) is the first step for citrate biosYnthesis, so the expression oi its encoded genes were paid more attention. Some studies through applying CS inhibitor on Satsuma manda- rin and tangelo proved that CS activity affect citrate level in citrus fruit; and similar role of CS was ob- tained by the study in navel orange. However, many reports believed that there was no clear relationship betw
出处
《果树学报》
CAS
CSCD
北大核心
2018年第1期118-127,共10页
Journal of Fruit Science
基金
国家自然科学基金(31401824)
湖南省教育厅资助科研项目(17B127)
国家现代农业(柑橘)产业技术体系(CARS-027)
湖南省自然科学基金(2017JJ3168)