The molecular events that characterize postripening grapevine berries have rarely been investigated and are poorly defined. In particular, a detailed definition of changes occurring during the postharvest dehydration, a process undertaken to make some particularly special wine styles, would be of great interest for both winemakers and plant biologists. We report an exhaustive survey of transcriptomic and metabolomic responses in berries representing six grapevine genotypes subjected to postharvest dehydration under identical controlled conditions. The modulation of phenylpropanoid metabolism clearly distinguished the behavior of genotypes, with stilbene accumulation as the major metabolic event, although the transient accumulation/depletion of anthocyanins and flavonols was the prevalent variation in genotypes that do not accumulate stilbenes. The modulation of genes related to phenylpropanoid/stilbene metabolism highlighted the distinct metabolomic plasticity of genotypes, allowing for the identification of candidate structural and regulatory genes. In addition to genotype-specific responses, a core set of genes was consistently modulated in all genotypes, representing the common features of berries undergoing dehydration and/or commencing senescence. This included genes controlling ethylene and auxin metabolism as well as genes involved in oxidative and osmotic stress, defense responses, anaerobic respiration, and cell wall and carbohydrate metabolism. Several transcription factors were identified that may control these shared processes in the postharvest berry. Changes representing both common and genotype-specific responses to postharvest conditions shed light on the cellular processes taking place in harvested berries stored under dehydrating conditions for several months.

The biochemical properties of PsbS protein, a nuclearencoded Photosystem II subunit involved in the high energy quenching of chlorophyll fluorescence, have been studied using preparations purified from chloroplasts or obtained by overexpression in bacteria. Despite the homology with chlorophyll a/b/xanthophyllbinding proteins of the Lhc family, native PsbS protein does not show any detectable ability to bind chlorophylls or carotenoids in conditions in which Lhc proteins maintain full pigment binding. The recombinant protein, when refolded in vitro in the presence of purified pigments, neither binds chlorophylls nor xanthophylls, differently from the homologous proteins LHCII, CP26, and CP29 that refold into stable pigment-binding complexes. Thus, it is concluded that if PsbS is a pigment-binding protein in vivo, the binding mechanism must be different from that present in other Lhc proteins. Primary sequence analysis provides evidence for homology of PsbS helices I and III with the central 2-fold symmetric core of chlorophyll a/b-binding proteins. Moreover, a structural homology owed to the presence of acidic residues in each of the two lumen-exposed loops is found with the dicyclohexylcarbodiimide/Ca 2؉ -binding domain of CP29. Consistently, both native and recombinant PsbS proteins showed [ 14 C]dicyclohexylcarbodiimide binding, thus supporting a functional basis for its homology with CP29 on the lumen-exposed loops. This domain is suggested to be involved in sensing low luminal pH. Photosystem II (PSII)1 of higher plants is a multisubunit membrane complex composed of many polypeptides that are encoded by the chloroplast or nuclear genes. Chloroplast gene products are located in the core complex where electron transport reactions are catalyzed, whereas the surrounding lightharvesting system is composed of nuclear-encoded chlorophyll a/b/xanthophyll proteins belonging to the Lhc family (1). Lhc proteins of PSII include Lhcb1-3 gene products that form heterotrimeric complexes (LHCII) located peripherally in the PSII⅐LHCII supercomplex and Lhcb4 -6 proteins, which form a layer of monomeric subunits located between the core complex and trimeric LHCII. Besides the role of harvesting light and transferring excitation energy to the PSII reaction center (RC), Lhc proteins are involved in regulative mechanisms aimed at both the optimization of excitation energy distribution between PSI and PSII and the protection of the PSII RC from photoinhibition when absorbed light exceeds the electron transport capacity of the chloroplast. The former mechanisms acting at moderate to low light intensity include the reversible phosphorylation of LHCII, which leads to the detachment of phospho-LHCII from PSII and its migration to stroma membranes where it transfers energy to PSI (2). The mechanisms of protection from photoinhibition are elicited at high light intensity and include the reversible phosphorylation of Lhcb4 (CP29) (3) and the xanthophyll cycle-dependent non-photochemical energy quenching (NPQ). In excess light conditions...

BackgroundThe definition of the terroir concept is one of the most debated issues in oenology and viticulture. The dynamic interaction among diverse factors including the environment, the grapevine plant and the imposed viticultural techniques means that the wine produced in a given terroir is unique. However, there is an increasing interest to define and quantify the contribution of individual factors to a specific terroir objectively. Here, we characterized the metabolome and transcriptome of berries from a single clone of the Corvina variety cultivated in seven different vineyards, located in three macrozones, over a 3-year trial period.ResultsTo overcome the anticipated strong vintage effect, we developed statistical tools that allowed us to identify distinct terroir signatures in the metabolic composition of berries from each macrozone, and from different vineyards within each macrozone. We also identified non-volatile and volatile components of the metabolome which are more plastic and therefore respond differently to terroir diversity. We observed some relationships between the plasticity of the metabolome and transcriptome, allowing a multifaceted scientific interpretation of the terroir concept.ConclusionsOur experiments with a single Corvina clone in different vineyards have revealed the existence of a clear terroir-specific effect on the transcriptome and metabolome which persists over several vintages and allows each vineyard to be characterized by the unique profile of specific metabolites.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0584-4) contains supplementary material, which is available to authorized users.

␣-Sarcoglycan is a component of the sarcoglycan complex of dystrophin-associated proteins. Mutations of any of the sarcoglycan genes cause specific forms of muscular dystrophies, collectively termed sarcoglycanopathies. Importantly, a deficiency of any specific sarcoglycan affects the expression of the others. Thus, it appears that the lack of sarcoglycans deprives the muscle cell of an essential, yet unknown function. In the present study, we provide evidence for an ecto-ATPase activity of ␣-sarcoglycan. ␣-Sarcoglycan binds ATP in a Mg Dystrophin is a large cytoskeletal protein associated with a complex of integral and peripheral membrane proteins collectively termed DAPs.1 Dystrophin is a long filamentous protein comprising four distinct structural domains: the amino-terminal domain, which binds F-actin, the rod-like central domain; the cysteine-rich domain, which binds the cytoplasmic portion of ␤-dystroglycan and syntrophins; and the carboxyl-terminal domain (1). The DAPs complex is composed of three subcomplexes: syntrophins, dystroglycans, and sarcoglycans (2, 3). Syntrophins are peripheral membrane proteins of unknown function that bind the carboxyl terminus of dystrophin (4, 5). Dystroglycans consist of two proteins derived from a common precursor protein: ␣-dystroglycan, a peripheral glycoprotein that binds extracellular matrix proteins like laminin-2 (merosin) and, in the neuromuscular junction, laminin-4 (agrin); and ␤-dystroglycan, an intrinsic membrane protein that binds dystrophin at its cytoplasmic tail and ␣-dystroglycan at the opposite end (6, 7). Therefore, the dystroglycans represent the link between the subsarcolemmal actin cytoskeleton and the extracellular matrix through dystrophin. Five sarcoglycans have been described: ␣-sarcoglycan (adhalin, 50 kDa), ␤-sarcoglycan (43 kDa), ␥-and ␦-sarcoglycans (35 kDa) (8 -10), and ⑀-sarcoglycan (11, 12). The function of the sarcoglycans remains unknown.Dystrophin is defective in Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy. In patients with DMD and in the mdx mouse, an animal model for DMD, all of the components of the DAPs are severely reduced at the sarcolemma (13, 14), even though they are almost normal at the neuromuscular junction (15).Mutations in the ␣-sarcoglycan gene, which is located on chromosome 17q21 (10), were demonstrated in limb girdle muscular dystrophy-2D (LGMD-2D), an autosomal recessive muscular dystrophy that affects both females and males (16,17). In LGMD-2D, ␤-and ␥-sarcoglycan were also absent or greatly reduced, whereas dystrophin and the dystroglycan complex were preserved (18). Similar modifications were also found in the skeletal muscle of the cardiomyopatic hamster, an animal model of this disease (19). Recently, mutations in the genes that encode for ␤-, ␥-, and ␦-sarcoglycan, located on chromosomes 4q12, 13q12, and 5q33-34, were discovered in LGMD-2E, -2C, and -2F, respectively (9,20,21). These mutations caused the absence not only of the respective protein product but also of the other three components...

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