Abscisic acid alleviates chilling injury in cold-stored peach fruit by regulating ethylene and hydrogen peroxide metabolism

Abscisic acid and ethylene coordinating fruit ripening under abiotic stress

Fleshy fruit metabolism is intricately influenced by environmental changes, yet the hormonal regulations underlying these responses remain poorly elucidated. ABA and ethylene, pivotal in stress responses across plant vegetative tissues, play crucial roles in triggering fleshy fruit ripening. Their actions are intricately governed by complex mechanisms, influencing key aspects such as nutraceutical compound accumulation, sugar content, and softening parameters. Both hormones are essential orchestrators of significant alterations in fruit development in response to stressors like drought, salt, and temperature fluctuations. These alterations encompass colour development, sugar accumulation, injury mitigation, and changes in cell-wall degradation and ripening progression. This review provides a comprehensive overview of recent research progress on the roles of ABA and ethylene in responding to drought, salt, and temperature stress, as well as the molecular mechanisms controlling ripening in environmental cues. Additionally, we propose further studies aimed at genetic manipulation of ABA and ethylene signalling, offering potential strategies to enhance fleshy fruit resilience in the face of future climate change scenarios.

PpERF-CRF3 selected by transcriptomic analysis plays key roles in the regulation of ABA alleviating chilling injury in peach fruit

Abscisic acid (ABA) is widely utilized to mitigate chilling injury (CI) of fruit. However, the molecular mechanism of ABA alleviates CI in peach fruit remain unclear. Herein, 10-4 M ABA treatment significantly mitigated the CI of peach fruit by reducing relative conductivity and malondialdehyde content, while increasing proline and endogenous ABA content. Transcriptomic analysis indicated that an abundant number of differentially expressed genes were altered by ABA treatment, which primarily enriched pathways such as plant hormone signal transduction, glycerophospholipid metabolism and phenylpropanoid biosynthesis. RNA-Seq results indicate that ABA modulates the transcription of genes involved in auxin, ABA and ethylene signal transduction, as well as in cell wall degradation, antioxidant, fatty acid desaturation and proline metabolism. RT-qPCR confirmed the RNA-Seq results, ABA treatment induced the transcription of proline metabolism related genes (PpP5CR2, PpP5CS, PpP5CS1) and PpERF-CRF3. Particularly noteworthy, as a nuclear protein, PpERF-CRF3 activated the expression of PpP5CR2 and PpP5CS by directly binding to their promoters and over-expression PpERF-CRF3 increased proline content and enhanced PpP5CR2 and PpP5CS expression. Overall, these findings suggest that ABA mitigates CI in peach fruit may be by mediating these pathways, and PpERF-CRF3 potentially involves this process by stimulating the expression of genes related to proline synthesis.

Abscisic acid biosynthesis, metabolism and signaling in ripening fruit

Fruits are highly recommended nowadays in human diets because they are rich in vitamins, minerals, fibers and other necessary nutrients. The final stage of fruit production, known as ripening, plays a crucial role in determining the fruit's quality and commercial value. This is a complex physiological process, which involves many phytohormones and regulatory factors. Among the phytohormones involved in fruit ripening, abscisic acid (ABA) holds significant importance. ABA levels generally increase during the ripening process in most fruits, and applying ABA externally can enhance fruit flavor, hasten softening, and promote color development through complex signal regulation. Therefore, gaining a deeper understanding of ABA's mechanisms in fruit ripening is valuable for regulating various fruit characteristics, making them more suitable for consumption or storage. This, in turn, can generate greater economic benefits and reduce postharvest losses. This article provides an overview of the relationship between ABA and fruit ripening. It summarizes the effects of ABA on ripening related traits, covering the biochemical aspects and the underlying molecular mechanisms. Additionally, the article discusses the interactions of ABA with other phytohormones during fruit ripening, especially ethylene, and provides perspectives for future exploration in this field.

Biochemical and molecular changes in peach fruit exposed to cold stress conditions

Storage or transportation temperature is very important for preserving the quality of fruit. However, low temperature in sensitive fruit such as peach can induce loss of quality. Fruit exposed to a specific range of temperatures and for a longer period can show chilling injury (CI) symptoms. The susceptibility to CI at low temperature varies among cultivars and genetic backgrounds. Along with agronomic management, appropriate postharvest management can limit quality losses. The importance of correct temperature management during postharvest handling has been widely demonstrated. Nowadays, due to long-distance markets and complex logistics that require multiple actors, the management of storage/transportation conditions is crucial for the quality of products reaching the consumer.Peach fruit exposed to low temperatures activate a suite of physiological, metabolomic, and molecular changes that attempt to counteract the negative effects of chilling stress. In this review an overview of the factors involved, and plant responses is presented and critically discussed. Physiological disorders associated with CI generally only appear after the storage/transportation, hence early detection methods are needed to monitor quality and detect internal changes which will lead to CI development. CI detection tools are assessed: they need to be easy to use, and preferably non-destructive to avoid loss of products.

Identification and characterization of Dof genes in Cerasus humilis

Introduction

Dof genes encode plant-specific transcription factors, which regulate various biological processes such as growth, development, and secondary metabolite accumulation.

Methods

We conducted whole-genome analysis of Chinese dwarf cherry (Cerasus humilis) to identify ChDof genes and characterize the structure, motif composition, cis-acting elements, chromosomal distribution, and collinearity of these genes as well as the physical and chemical properties, amino acid sequences, and phylogenetic evolution of the encoded proteins.

Results

The results revealed the presence of 25 ChDof genes in C. humilis genome. All 25 ChDof genes could be divided into eight groups, and the members of the same group had similar motif arrangement and intron-exon structure. Promoter analysis showed that cis-acting elements responsive to abscisic acid, low temperature stress, and light were dominant. Transcriptome data revealed that most ChDof genes exhibited tissue-specific expression. Then, we performed by qRT-PCR to analyze the expression patterns of all 25 ChDof genes in fruit during storage. The results indicated that these genes exhibited different expression patterns, suggesting that they played an important role in fruit storage.

Discussion

The results of this study provide a basis for further investigation of the biological function of Dof genes in C. humilis fruit.