What controls fleshy fruit acidity? A review of malate and citrate accumulation in fruit cells

Abstract

Fleshy fruit acidity is an important component of fruit organoleptic quality and is mainly due to the presence of malic and citric acids, the main organic acids found in most ripe fruits. The accumulation of these two acids in fruit cells is the result of several interlinked processes that take place in different compartments of the cell and appear to be under the control of many factors. This review combines analyses of transcriptomic, metabolomic, and proteomic data, and fruit process-based simulation models of the accumulation of citric and malic acids, to further our understanding of the physiological mechanisms likely to control the accumulation of these two acids during fruit development. The effects of agro-environmental factors, such as the source:sink ratio, water supply, mineral nutrition, and temperature, on citric and malic acid accumulation in fruit cells have been reported in several agronomic studies. This review sheds light on the interactions between these factors and the metabolism and storage of organic acids in the cell.

Genome-Wide Association in Tomato Reveals 44 Candidate Loci for Fruit Metabolic Traits

“…Figure 4B, representing the local pattern of LD around the peak SNP, suggests that the LD level is relatively low in this genomic region. From a functional point of view, citrate and malate are two organic compounds found in most ripe fruits (Etienne et al, 2013) and have been demonstrated to be highly correlated with many important regulators of ripening in studies that have investigated early fruit development (Mounet et al, 2009;Centeno et al, 2011). This result suggests that, in this study, we were able to identify a peak SNP that is located near one or several putative candidate gene(s) playing a crucial role in the citrate and malate metabolic pathways.…”

Streptococcus pyogenes Malate Degradation Pathway Links pH Regulation and Virulence

“…In this regard, transcriptome profiling revealed that one of the most highly differentially activated gene clusters under conditions of acid stress and glucose starvation and in murine soft tissue encodes a putative operon of two genes predicted to function in the catabolism of malate (10), annotated as the malic permease (maeP) and the malic enzyme (maeE) (Fig. 1A).The dicarboxylic organic acid malate is found in abundance in tissue and in the environment, so it is not surprising that numerous malate degradation pathways have been identified among both prokaryotic and eukaryotic organisms (11)(12)(13)(14)(15)(16)(17). In lactic acid bacteria, two distinct pathways have been identified that make very different contributions to physiology.…”

“…The dicarboxylic organic acid malate is found in abundance in tissue and in the environment, so it is not surprising that numerous malate degradation pathways have been identified among both prokaryotic and eukaryotic organisms (11)(12)(13)(14)(15)(16)(17). In lactic acid bacteria, two distinct pathways have been identified that make very different contributions to physiology.…”

Impact of Harvesting Time and Length of Cold Storage Period On Physiological and Quality Traits of Four Quince Genotypes (Cydonia Oblonga Mill.)

“…The soluble sugar (sucrose, fructose, and glucose) contents resulting from the hydrolysis of starch during ripening are determined by evaluation of TSS concentration (Etienne et al 2013). Khoush Ghalb et al (2008) showed that Asian pear at harvesting had large amounts of sucrose that was converted into simple sugars during prolonged storage, which leads to increase of TSS.…”