The type-B authentic response regulator (ARR-B) family members serve as DNA-binding transcriptional regulators, whose activities are probably regulated by phosphorylation/dephosphorylation, resulting in the rapid induction of type-A ARR genes. Type-B ARRs are believed to be involved in many biological processes, including cytokinin signaling, plant growth, and stress responses through a chaperone or by isomerization of proline residues during protein folding. The public availability of complete peach genome sequences allows the identification of 23 ARR-B genes by HMMER and blast analysis. Scaffold locations of these genes in the peach genome were determined, and the protein domain and motif organization of peach type-B ARRs were analyzed. The phylogenetic relationships between peach type-B ARRs were also assessed. The expression profiles of peach ARR-B genes revealed that most of the type-B ARRs showed high expression levels in tissues undergoing rapid cell division and may engage more cytokinins, like half-opened flowers, fruits at expansion stages, and young leaves. These findings not only contribute to a better understanding of the complex regulation of the peach ARR-B gene family, but also provide valuable information for future research in peach functional genomics.

Phenolic compounds and their derivatives play a major role in the intensity and characteristics of grape (Vitis vinifera) astringency. The present study investigated the relationship between phenolic composition and astringency of six commercial table grape varieties (two of each white-, red-, and black-skinned). Qualitative and quantitative liquid chromatography-mass spectrometry analysis was used to identify the variety-specific phenolic profiles in the skins and total astringency intensity was assessed and described by a trained sensory panel. Thirty phenolic compounds were identified among the six varieties. Principal component analysis of the phenolic profiles revealed that the intensity of astringency of grape skin was positively correlated with catechin, epicatechin, epicatechin-3-O-gallate, and proanthocyanidin dimers B1, B2, and B3. A further orthogonal partial least-squares discrimination analysis of these compounds showed that catechin was the substance most strongly and positively correlated (R = 0.904) with grape skin astringency.

The glycogen synthase kinase 3/shaggy kinase (GSK3) is a serine/threonine kinase that plays important roles in brassinosteroid signaling, abiotic stress responses, cell division, and elongation, etc. In this study, we characterized seven grape GSK3 genes, showing high similarities with homologs from other species including Arabidopsis, white pear, apple, orange, and peach. Gene chip microarray data derived from an online database revealed very diverse developmental and tissue-specific expression patterns of VvSKs. VvSK3 and VvSK7 showed much higher expression levels in almost every tissue compared with other members. VvSK7 was highly enriched in young tissues like berries before the veraison stage, young leaves and green stems, etc., but immediately downregulated after these tissues entered maturation or senescence phases. Prediction of cis-elements in VvSK promoters indicated that VvSKs might be sensitive to light stimulation, which is further confirmed by the qPCR data. Constitutive overexpression of VvSK7 in Arabidopsis leads to dwarf plants that resembles BR-deficient mutants. The photosynthetic rate was significantly reduced in these plants, even though they accumulated more chlorophyll in leaves. Transient overexpression of VvSKs in tomatoes delayed the fruit ripening process, consistent with the observation in grapevine which blocks VvSKs by EBR- or BIKININ-promoted berry expansion and soluble solids accumulation. Data presented in the current study may serve as a theoretical basis for the future application of BRs or related compounds in quality grape production.

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The application of genetic information in agricultural production is an important issue, which is highly worthy of attention. Gene expression data can accurately reflect the growth and metabolic status of plants, with which we can predict and monitor the nutritional requirements of plants and then derive accurate fertilization strategies. In this study, to verify the feasibility and workability of gene information-based fertilization strategies and to figure out the specific nutritional requirements of grapevine (Vitis vinifera L.) at various developmental stages, the expression levels of 13 N-P-K uptake and metabolism genes and their responses to fertilization during the flowering and berry development stages were validated by using quantitative polymerase chain reaction (PCR). The results showed that in the particular stages where N-P-K uptake and metabolism genes were highly expressed, these genes also showed more positive responses to fertilization and the grape quality was more dramatically improved. This proved the feasibility and workability of this novel fertilization strategy. The nutritional requirements of grapevine during the flowering and berry developmental phases were summarized in terms of gene expression levels, in which grapevine needs more P at the flowering stage, more N at the first berry expansion stage, less nutrient at the seed stone hardening stage, and more P and K at the second berry expansion stage and the veraison stage. The present study is one of the novel and initial findings regarding the application of fertilizers in vineyards for better cultivation of grapevine during common cultural practices. Grapevine is one of the world's most economically important fruit crops (He, 1998;Kong, 2004). It is is highly responsive to the application of fertilizers and has been reported as a heavy feeder of N, P, and K. Fertilization of the soil is one of the most important viticulture techniques, with a great effect on the vineyard yield and the grape quality. Fertilizer application usually results in increased yield; however, excessive or unbalanced applications can have negative effects on the yield and fruit quality. Traditional fertilization strategies are dominantly based on phenology and personal Abbreviations: FE, fertilization; SC, sample collecting; VvAS, V. vinifera asparagine synthetase; VvGDH, V. vinifera glutamate dehydrogenase; VvGS, V. vinifera glutamine synthetase; VvNiR, V. vinifera nitrite reductase; VvNR, V. vinifera Core Ideas• This approach is more accurate and reliable than traditional fertilization strategies.• This study verified the feasibility and workability of gene expression-based fertilization strategies.• The specific nutritional requirements of grapevine at different developmental stages were depicted in the level of gene expression.