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The WUSCHEL-related homeobox (WOX) transcription factor family plays critical roles in plant growth, development, and stress adaptation, but the biological functions in response to various stress of the WOX gene family have not been extensively researched in grapevine (Vitis vinifera). In this study, 12 grapevine WOXs were identified from the grapevine genome. Quantitative PCR and microarray expression profiling found that the expression of WOXs had an obvious tissue-specific pattern. Conjoint analysis between various tissues and treated materials indicated VvWUS1 expression is associated with expression of genes from grapevine rupestris stem pitting-associated virus; and VvWOX3 with grapevine fanleaf virus. The gene expression patterns of the WOXs in grape were different under salt stress, with VvWOX8/9 , VvWUS1 , and VvWOX3 responding more strongly to salt stress than control by 18.20-, 9.50-, and 9.19-fold. This study further improves understanding of the evolution and function of the WOX gene family, and offers a theoretical framework and reference for breeding grapevine to better tolerate adversity and permit cultivation of seedlings free of viruses. WOX is a family of genes that help regulate how plants develop and also respond to stress. In this study, 12 WOX genes were identified in grapes and analysed by bioinformatic methods. Coanalysis of different expression patterns in grapes showed that two of these genes respond to specific viruses and effectively block virus replication and infestation. Another gene was the most sensitive to salt stress. This study provides preliminary evidence that these three genes are key to resistance to salt and to viruses in grape, providing vital candidate genes for grapevine breeding [ABSTRACT FROM AUTHOR]

Soil salinisation is an important abiotic stress faced in grape cultivating, leading to weakened plant vigour and reduced fruit quality. Melatonin as a novel hormone has shown positive exogenous application value. Therefore, this study used wine grape (Vitis vinifera) 'Pinot Noir' as a test material to investigate the changes of foliar spraying with different concentrations of melatonin on the physiology and fruit quality of wine grapes in a field under simulated salt stress (200 mmol L−1 NaCl). The results showed that foliar spraying of melatonin significantly increased the intercellular CO2 concentration, maximum photochemical quantum yield of PSII, relative chlorophyll and ascorbic acid content of the leaves, as well as the single spike weight, 100-grain weight, transverse and longitudinal diameters, malic acid, α-amino nitrogen and ammonia content of fruits, and decreased the initial fluorescence value of leaves, ascorbate peroxidase activity, glutathione content, fruit transverse to longitudinal ratio and tartaric acid content of plants under salt stress. Results of the comprehensive evaluation of the affiliation function indicated that 100 μmol L−1 melatonin treatment had the best effect on reducing salt stress in grapes. In summary, melatonin application could enhance the salt tolerance of grapes by improving the photosynthetic capacity of grape plants under salt stress and promoting fruit development and quality formation, and these results provide new insights into the involvement of melatonin in the improvement of salt tolerance in crop, as well as some theoretical basis for the development and industrialisation of stress-resistant cultivation techniques for wine grapes. In this study, by foliar spraying of 100 and 300 μmol L−1 melatonin, the results showed that melatonin was able to reduce the damage of salt stress on the photosynthetic system and antioxidant system of wine grape (Vitis vinifera) leaves, and also improve the shape of the fruit and the intrinsic quality of the grape berries, such as sugar, acid, and nitrogenous compounds. Melatonin at 100 μmol L−1 was found to be the most effective. [ABSTRACT FROM AUTHOR]

Plant acclimation to salt and alkali stress is closely linked to the ability of the antioxidant system to mediate the scavenging of reactive oxygen species (ROS). In this study, we investigated the effects of salt stress and alkali stress on ROS, antioxidant enzymes, transcriptome, and metabolome. The results showed that the levels of superoxide anions, hydrogen peroxide, malondialdehyde, and electrolyte leakage increased under salt and alkali stress, with higher concentrations observed under alkali stress than salt stress. The activities of superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11), glutathione reductase (EC 1.6.4.2), dehydroascorbate reductase (EC 1.8.5.1), and monodehydroascorbate reductase (EC 1.6.5.4) varied under salt and alkali stress. The transcriptome analysis revealed the induction of signal transduction and metabolic processes and differential expression of genes encoding antioxidant enzymes in response to salt and alkali stress. The metabolome analysis demonstrated increased ascorbic acid and glutathione under salt stress, while most phenolic acids, flavonoids, and alkaloids increased under salt and alkali stress. Integrative analysis of the metabolome and transcriptome data revealed that the flavonoid biosynthesis pathway played a key role in the grapevine's response to salt stress. The total flavonoid content increased under salt and alkali stress, but the accumulation of flavonoids was higher under salt stress than alkali stress. In conclusion, our findings indicate significant differences in the antioxidant defense of grapevines under these two stresses, providing insight into distinct acclimation mechanisms in grapevine under salt and alkali stress. [ABSTRACT FROM AUTHOR]

Salt stress is a dominant environmental factor that restricts the growth and yield of crops. Nitrogen is an essential mineral element for plants, regulates various physiological and biochemical processes, and has been reported to enhance salt tolerance in plants. However, the crosstalk between salt and nitrogen in grapes is not well understood. In this study, we found that nitrogen supplementation (0.01 and 0.1 mol L−1 NH4NO3) significantly increased the accumulation of proline, chlorophyll, Na+, NH4+, and NO3−, while it reduced the malondialdehyde content and inhibited photosynthetic performance under salt stress conditions (200 mmol L−1 NaCl). Further transcriptome and metabolome analyses showed that a total of 4890 differentially expressed genes (DEGs) and 753 differently accumulated metabolites (DAMs) were identified. Joint omics results revealed that plant hormone signal transduction pathway connected the DEGs and DAMs. In‐depth analysis revealed that nitrogen supplementation increased the levels of endogenous abscisic acid, salicylic acid, and jasmonic acid by inducing the expression of 11, 4, and 13 genes related to their respective biosynthesis pathway. In contrast, endogenous indoleacetic acid content was significantly reduced due to the remarkable regulation of seven genes of its biosynthetic pathway. The modulation in hormone contents subsequently activated the differential expression of 13, 10, 12, and 29 genes of the respective downstream hormone signaling transduction pathways. Overall, all results indicate that moderate nitrogen supplementation could improve salt tolerance by regulating grape physiology and endogenous hormone homeostasis, as well as the expression of key genes in signaling pathways, which provides new insights into the interactions between mineral elements and salt stress. [ABSTRACT FROM AUTHOR]

Background: Soil salinization and alkalization are widespread environmental problems that limit grapevine (Vitis vinifera L.) growth and yield. However, little is known about the response of grapevine to alkali stress. This study investigated the differences in physiological characteristics, chloroplast structure, transcriptome, and metabolome in grapevine plants under salt stress and alkali stress. Results: We found that grapevine plants under salt stress and alkali stress showed leaf chlorosis, a decline in photosynthetic capacity, a decrease in chlorophyll content and Rubisco activity, an imbalance of Na+ and K+, and damaged chloroplast ultrastructure. Fv/Fm decreased under salt stress and alkali stress. NPQ increased under salt stress whereas decreased under alkali stress. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed the differentially expressed genes (DEGs) induced by salt stress and alkali stress were involved in different biological processes and have varied molecular functions. The expression of stress genes involved in the ABA and MAPK signaling pathways was markedly altered by salt stress and alkali stress. The genes encoding ion transporter (AKT1, HKT1, NHX1, NHX2, TPC1A, TPC1B) were up-regulated under salt stress and alkali stress. Down-regulation in the expression of numerous genes in the ‘Porphyrin and chlorophyll metabolism’, ‘Photosynthesis-antenna proteins’, and ‘Photosynthesis’ pathways were observed under alkali stress. Many genes in the ‘Carbon fixation in photosynthetic organisms’ pathway in salt stress and alkali stress were down-regulated. Metabolome showed that 431 and 378 differentially accumulated metabolites (DAMs) were identified in salt stress and alkali stress, respectively. L-Glutamic acid and 5-Aminolevulinate involved in chlorophyll synthesis decreased under salt stress and alkali stress. The abundance of 19 DAMs under salt stress related to photosynthesis decreased. The abundance of 16 organic acids in salt stress and 22 in alkali stress increased respectively. Conclusions: Our findings suggested that alkali stress had more adverse effects on grapevine leaves, chloroplast structure, ion balance, and photosynthesis than salt stress. Transcriptional and metabolic profiling showed that there were significant differences in the effects of salt stress and alkali stress on the expression of key genes and the abundance of pivotal metabolites in grapevine plants. [ABSTRACT FROM AUTHOR]

In higher plants, light capture of chlorophyll a/b binding protein (Lhc) plays a crucial role in the plant's response to adverse environment. So far, the family has not been systematically identified in grapes. In this study, 20 VvLhcs were identified in the grape genome, which were distributed in 13 of 19 grape chromosomes and divided into 7 developing branches. The results of gene duplication analysis showed that 6 VvLhcs formed fragment duplication events, while there was no tandem duplication in VvLhcs. Exon–intron structure analysis showed that they had a wide number of exons. Protein conserved motif analysis showed that VvLhcs contained more similar motif structures in the same phylogenetic branch. The cis-acting elements in the VvLhcs promoter region mainly respond to light, plant hormones and abiotic stresses. In addition, qRT-PCR results showed that different proportions of salt stress and red-blue light affected the expression of VvLhcs and the expression patterns of genes in different grape varieties were different. The results for further study on different grape varieties in different combinations of red and blue light of the Lhc provide a theoretical basis. [ABSTRACT FROM AUTHOR]