Contents Summary532I.533II.533III.533IV.535V.537VI.539VII.539VIII.544IX.546548

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BackgroundGrapevine (Vitis vinifera L.) is the most important Mediterranean fruit crop, used to produce both wine and spirits as well as table grape and raisins. Wine and table grape cultivars represent two divergent germplasm pools with different origins and domestication history, as well as differential characteristics for berry size, cluster architecture and berry chemical profile, among others. ‘Sultanina’ plays a pivotal role in modern table grape breeding providing the main source of seedlessness. This cultivar is also one of the most planted for fresh consumption and raisins production. Given its importance, we sequenced it and implemented a novel strategy for the de novo assembly of its highly heterozygous genome.ResultsOur approach produced a draft genome of 466 Mb, recovering 82% of the genes present in the grapevine reference genome; in addition, we identified 240 novel genes. A large number of structural variants and SNPs were identified. Among them, 45 (21 SNPs and 24 INDELs) were experimentally confirmed in ‘Sultanina’ and six SNPs in other 23 table grape varieties. Transposable elements corresponded to ca. 80% of the repetitive sequences involved in structural variants and more than 2,000 genes were affected in their structure by these variants. Some of these genes are likely involved in embryo development, suggesting that they may contribute to seedlessness, a key trait for table grapes.ConclusionsThis work produced the first structural variants and SNPs catalog for grapevine, constituting a novel and very powerful tool for genomic studies in this key fruit crop, particularly useful to support marker assisted breeding in table grapes.

The yield of 24 commercial varieties and accessions of common bean (Phaseolus vulgaris) has been determined at different sites in Chile and Bolivia. Statistical analysis was performed in order to characterize whether a particular variety was more or less stable in yield under different environmental conditions. Amongst these, two varieties have been identified for more detailed study: one variety has a higher than average yield under unstressed conditions but is strongly affected by stress, and another has a reduced yield under unstressed conditions but is less affected by stress. The contrasting rate of abscission of the reproductive organs under drought stress was clearly consistent with these differences. The more tolerant genotype shows a great deal of plasticity at the biochemical and cellular level when exposed to drought stress, in terms of stomatal conductance, photosynthetic rate, abscisic acid synthesis, and resistance to photoinhibition. By contrast, the former lacks such plasticity, but shows an enhanced tendency for a morphological response, the movement of leaves, which appears to be its principal response to drought stress.

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Artículo de publicación ISIRoot hypoxia in fruit trees affects growth, vegetative development, and reproductive development, which is reflected in low productivity, poor fruit quality, and premature decay of trees. Using Illumina Hiseq2000, we performed transcriptome analysis of roots from two different rootstocks, ‘Mariana 2624’ and ‘Mazzard F12/1,’ which are tolerant and sensitive to hypoxia, respectively. Transcriptomes from control and hypoxia-stressed plants (6, 24, and 72 h) were compared, using Prunus persica (L.) as reference genome. Hypoxic conditions altered the transcription in both genotypes. There were a high number of common differentially expressed genes (DEG) between the two genotypes for each sampling time, but also exclusive DEG for each genotype, with a few DEG that presented opposite modes of regulations during the hypoxia treatment. An important group of DEGs exclusively upregulated in the tolerant genotype are associated to enzymes of posttranslational protein modifications, such as leucinerich repeat (LRR), kinases and ubiquitin-protein ligases, regulation of transcription, and process of oxide reduction. Singular enrichment analysis of gene ontology (GO), detected at least 115 GOs involved in the response to root hypoxia in the sensitive and/or tolerant genotypes. At least 25 GOs were identified as part of the baseline differences between the genotypes, most GO were disturbed in the sensitive genotype. The contribution from the baseline gene expression to the differential response between the Prunus genotypes is evidence that the resistant genotype is already Bprepared^ for a hypoxia event. An example are GO BP:0042221 of response to chemical stimulus; BP:0006979 of response to oxidative stress; MF:0016209 of antioxidant activity; MF:0016684 of oxidoreductase activity, acting on peroxide as acceptor; and MF:0004601 of peroxidase activity, which were disturbed only in the sensitive genotype, but not in the tolerant.FONDECYT (No. 1121117) and CEAF_R08I100

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The photosynthetic characteristics of two contrasting varieties of common bean (Phaseolus vulgaris) have been determined. These varieties, Arroz and Orfeo, differ in their productivity under stress conditions, resistance to drought stress, and have distinctly different stomatal behaviour. When grown under conditions of high irradiance and high temperature, both varieties displayed evidence of photosynthetic acclimation at the chloroplast level-there was an increase in chlorophyll a/b ratio, a decreased content of Lhcb proteins, and an increased xanthophyll cycle pool size. Both varieties also showed reduced chlorophyll content on a leaf area basis and a decrease in leaf area. Both varieties showed an increase in leaf thickness but only Arroz showed the characteristic elongated palisade cells in the high light-grown plants; Orfeo instead had a larger number of smaller, rounded cells. Differences were found in stomatal development: whereas Arroz showed very little change in stomatal density, Orfeo exhibited a large increase, particularly on the upper leaf surface. It is suggested that these differences in leaf cell structure and stomatal density give rise to altered rates of photosynthesis and stomatal conductance. Whereas, Arroz had the same photosynthetic rate in plants grown at both low and high irradiance, Orfeo showed a higher photosynthetic capacity at high irradiance. It is suggested that the higher yield of Orfeo compared with Arroz under stress conditions can be explained, in part, by these cellular differences.