Benhong Wu

Transcriptomic analysis of grape (Vitis vinifera L.) leaves during and after recovery from heat stress

BackgroundGrapes are a major fruit crop around the world. Heat stress can significantly reduce grape yield and quality. Changes at the molecular level in response to heat stress and subsequent recovery are poorly understood. To elucidate the effect of heat stress and subsequent recovery on expression of genes by grape leaves representing the classic heat stress response and thermotolerance mechanisms, transcript abundance of grape (Vitis vinifera L.) leaves was quantified using the Affymetrix Grape Genome oligonucleotide microarray (15,700 transcripts), followed by quantitative Real-Time PCR validation for some transcript profiles.ResultsWe found that about 8% of the total probe sets were responsive to heat stress and/or to subsequent recovery in grape leaves. The heat stress and recovery responses were characterized by different transcriptional changes. The number of heat stress-regulated genes was almost twice the number of recovery-regulated genes. The responsive genes identified in this study belong to a large number of important traits and biological pathways, including cell rescue (i.e., antioxidant enzymes), protein fate (i.e., HSPs), primary and secondary metabolism, transcription factors, signal transduction, and development. We have identified some common genes and heat shock factors (HSFs) that were modulated differentially by heat stress and recovery. Most HSP genes were upregulated by heat stress but were downregulated by the recovery. On the other hand, some specific HSP genes or HSFs were uniquely responsive to heat stress or recovery.ConclusionThe effect of heat stress and recovery on grape appears to be associated with multiple processes and mechanisms including stress-related genes, transcription factors, and metabolism. Heat stress and recovery elicited common up- or downregulated genes as well as unique sets of responsive genes. Moreover, some genes were regulated in opposite directions by heat stress and recovery. The results indicated HSPs, especially small HSPs, antioxidant enzymes (i.e., ascorbate peroxidase), and galactinol synthase may be important to thermotolerance of grape. HSF30 may be a key regulator for heat stress and recovery, while HSF7 and HSF1 may only be specific to recovery. The identification of heat stress or recovery responsive genes in this study provides novel insights into the molecular basis for heat tolerance in grape leaves.

Inheritance of sugars and acids in berries of grape (Vitis vinifera L.)

Inheritance patterns for table grape sugars and organic acids were investigated on three cross offspring populations during two successive years. Glucose and fructose were the predominant sugars in progeny berries with only trace amounts of sucrose. Total sugar content showed additive inheritance and the broad-sense heritability ranged from 0.61 to 0.84. The means of progeny sugar content were lower than mean parent values. Inheritance of malic acid was strongly additive and the broad-sense heritability varied from 0.73 to 0.89. The means of progeny malic acid content were higher than mean parent values. Tartaric acid was mainly controlled by non-additive effect and the broad-sense heritability varied from 0.59 to 0.84. The means of progeny tartaric acid content were lower than mean parent values. Inheritance of the total acid content was strongly additive and was mainly influenced by malic acid. The broad-sense heritability of total acid varied from 0.53 to 0.90.

Anthocyanin biosynthesis is differentially regulated by light in the skin and flesh of white-fleshed and teinturier grape berries

AbstractMain conclusionLight exclusion reduces the concentration and modifies the composition of grape anthocyanins, by altering the expression of genes involved in anthocyanin biosynthesis and transport, in a cultivar- and tissue-specific manner. Unlike most grapes, teinturier grapes accumulate anthocyanins both in skin and flesh. However, the concentration and composition of anthocyanins in both tissues differ, providing a valuable system to study tissue-specific regulation of anthocyanin synthesis. Furthermore, little is known about the mechanisms controlling the sensitivity of anthocyanin accumulation to light. Here, light was excluded from Gamay (white-fleshed) and Gamay Fréaux (teinturier mutant) berries throughout berry development. Under light-exposed conditions, the skin of Gamay Fréaux accumulated the highest level of anthocyanins, followed by the skin of Gamay, while the pulp of Gamay Fréaux had much lower anthocyanins than the skins. Network analysis revealed the same order on the number of significant correlations among metabolites and transcripts in the three colored tissues, indicating a higher connectivity that reflects a higher efficiency of the anthocyanin pathway. Compared to light conditions, light exclusion reduced the total amount of anthocyanins, most severely in the skin of Gamay and to a lesser extent in the flesh and skin of Gamay Fréaux. Coordinated decrease in the transcript abundance of structural, regulatory and transporter genes by light exclusion correlated with the reduced anthocyanin concentration in a cultivar- and tissue-specific manner. Moreover, light exclusion increased the ratio of dihydroxylated to trihydroxylated anthocyanins, in parallel with F3′H and F3′5′H transcript amounts. Sugars and ABA only play a limited role in the control of anthocyanin synthesis in the berries, in contrast with what has been described in cell suspensions. This study provides novel insights into the regulation of anthocyanin in wild type and teinturier cultivars.

CIELAB Coordinates in Response to Berry Skin Anthocyanins and Their Composition in Vitis

Berry skin color OIV index, anthocyanin composition, and content of 78 grape cultivars were surveyed using a CIELAB system and high-performance liquid chromatography (HPLC)-mass spectrometry (MS) coupled with photodiode array detection. There were high correlations between L*, b*, and color, while a* was not a representative parameter. L* and b* values declined as berry skin color OIV became darker, and a* increased as berry skin color OIV became darker in pink and red grape cultivars only. The composition and content of anthocyanins varied widely among the cultivars. Total anthocyanins and types of anthocyanins were significantly correlated with color OIV parameters. Through multiple linear regression analysis, cyanidin derivatives had a positive effect on values of L* and b*. Delphinidin derivatives had positive effects on the value of a*. The CIELAB system gave good results for differentiation of grape berry skin color OIV.

Comparative assessment of sugar and malic acid composition in cultivated and wild apples

Soluble sugar and malic acid contents in mature fruits of 364 apple accessions were quantified using high-performance liquid chromatography (HPLC). Fructose and sucrose represented the major components of soluble sugars in cultivated fruits, whilst fructose and glucose were the major items of sugars in wild fruits. Wild fruits were significantly more acidic than cultivated fruits, whilst the average concentration of total sugars and sweetness index were quite similar between cultivated and wild fruits. Thus, our study suggests that fruit acidity rather than sweetness is likely to have undergone selection during apple domestication. Additionally, malic acid content was positively correlated with glucose content and negatively correlated with sucrose content. This suggests that selection of fruit acidity must have an effect on the proportion of sugar components in apple fruits. Our study provides information that could be helpful for future apple breeding.

Inheritance of anthocyanins in berries of Vitis vinifera grapes

Inheritance patterns for table grape anthocyanins were investigated on three cross offspring populations during two successive years. Sixteen anthocyanins were detected, and all were monoglucoside derivatives. The proportion of anthocyanins in the maternal parent determined the proportion of anthocyanins in the offspring. But the absolute content of the maternal parent had no significant effect on progenies. Peonidin 3-O-glucoside and malvidin 3-O-glucoside were the most abundant anthocyanins, not only in the maternal parent but also in the progenies. The presence or absence of anthocyanins in grape skin was inheritance of a quality character controlled by oligogenes, and anthocyanins content was a quantitative character controlled by polygenes. Via principal component (PC) analysis, factors that affected the total content of cross progeny populations were peonidin 3-O-glucoside, malvidin 3-O-glucoside, delphinidin 3-O-glucoside, cyanidin 3-O-glucoside, petunidin 3-O-glucoside, peonidin 3-O-(6-O-coumaryl)-glucoside, and malvidin 3-O-(6-O-coumaryl)-glucoside. Anthocyanins content was a high broad sense heritability character (H2), and H2 was stable in different cross combinations (ranging from 0.65 to 0.98).

Peach fruit growth in relation to the leaf-to-fruit ratio, early fruit size and fruit position

Summary To study the influences of assimilate availability, early fruit size and fruit position on fruit growth, experiments were conducted on an early-maturing peach (Prunus persica) cv.‘Alexandra’ in 1992 and a late-maturing peach cv.‘Suncrest’ in 1993. Leaf-to-fruit ratio (LFR) was used to manipulate assimilate availability. For each LFR, the distribution patterns of fruits along the fruit-bearing shoot were adjusted to one of four situations: 1) fruits were uniformly distributed on the leafy shoots; 2) fruits were located on the basal part of the fruit-bearing shoot with leaves on the distal part; 3) fruits were located on the distal part of the fruit-bearing shoot with leaves on the basal part; or 4) half of the fruits were distributed along the leafy shoots and the other half on the distal part of the fruit-bearing shoot. The fruit-bearing shoot base was girdled and the apical bud was removed. Fruit growth was expressed as dry weight calculated from continuously measured diameter. The effects of LFR, fruit position and early fruit size were analysed using a linear mixed-effects model. The results showed that LFR increased fruit dry weight and advanced fruit maturity date. Early fruit size had a significant influence on fruit growth. Fruit position slightly influenced its growth. Fruit closer to leafy shoots appeared to have higher fruit growth than more distal fruit, especially when there was intense assimilate competition. However, in most cases, the effect of fruit position was not significant.

Changes of Polyphenols, Sugars, and Organic Acid in 5 Vitis Genotypes during Berry Ripening

UNLABELLED The concentrations of sugars, organic acids, and polyphenols during berry ripening in 5 grape genotypes were analyzed using HPLC and HPLC-MS to determine which were correlated. Veraison is critical stage during grape berry development, and marks the beginning of ripening. Glucose and fructose accumulated sharply in a 1: 1ratio, though the concentration of fructose was slightly higher than that of glucose at maturation. Malic acid and tartaric acid were the dominant organic acids, and they decreased rapidly during berry ripening. The 5 cultivars contained 28 anthocyanins and 8 other polyphenols. All anthocyanins accumulated and were positively correlated with the sugars and negatively correlated with the organic acids. Hydroxycinnamic acids declined and were positively correlated with anthocyanin contents. Changes in flavanols and flavonols different among the 5 genotypes, with flavonols positively correlated with anthocyanin content, but the flavanols procyanidin B1and epicatechin negatively correlated with anthocyanins content. There were obvious differences in patterns of change of polyphenols among 5 grape genotypes. PRACTICAL APPLICATION The results could be used for improving grape berry quality during ripening and developing a comprehensive database of primary and secondary metabolites in the Vitis for grape breeding.

Construction of a high-density genetic map and QTLs mapping for sugars and acids in grape berries

BackgroundQTLs controlling individual sugars and acids (fructose, glucose, malic acid and tartaric acid) in grape berries have not yet been identified. The present study aimed to construct a high-density, high-quality genetic map of a winemaking grape cross with a complex parentage (V. vinifera × V. amurensis) × ((V. labrusca × V. riparia) × V. vinifera), using next-generation restriction site-associated DNA sequencing, and then to identify loci related to phenotypic variability over three years.ResultsIn total, 1 826 SNP-based markers were developed. Of these, 621 markers were assembled into 19 linkage groups (LGs) for the maternal map, 696 for the paternal map, and 1 254 for the integrated map. Markers showed good linear agreement on most chromosomes between our genetic maps and the previously published V. vinifera reference sequence. However marker order was different in some chromosome regions, indicating both conservation and variation within the genome. Despite the identification of a range of QTLs controlling the traits of interest, these QTLs explained a relatively small percentage of the observed phenotypic variance. Although they exhibited a large degree of instability from year to year, QTLs were identified for all traits but tartaric acid and titratable acidity in the three years of the study; however only the QTLs for malic acid and β ratio (tartaric acid-to-malic acid ratio) were stable in two years. QTLs related to sugars were located within ten LGs (01, 02, 03, 04, 07, 09, 11, 14, 17, 18), and those related to acids within three LGs (06, 13, 18). Overlapping QTLs in LG14 were observed for fructose, glucose and total sugar. Malic acid, total acid and β ratio each had several QTLs in LG18, and malic acid also had a QTL in LG06. A set of 10 genes underlying these QTLs may be involved in determining the malic acid content of berries.ConclusionThe genetic map constructed in this study is potentially a high-density, high-quality map, which could be used for QTL detection, genome comparison, and sequence assembly. It may also serve to broaden our understanding of the grape genome.

Anthocyanin Accumulation in Various Organs of a Teinturier Cultivar (Vitis vinifera L.) during the Growing Season

The anthocyanin composition and concentration of various organs of teinturier grape Yan-73 were studied throughout the growing season. Nineteen anthocyanins were identified by HPLC-MS as monoglucosides and their derivatives. Anthocyanin composition and concentration varied among grape organs and by developmental stage. Skin anthocyanins were mainly composed of malvidin derivatives, while peonidin derivatives were the most dominant anthocyanins in the pulp. Both malvidin and peonidin derivatives were predominant components in carpopodia (swollen pedicel at point of berry attachment), berry pedicels, leaf lamina, vein and petioles, and living bark at the base of the shoot. Anthocyanins were very low before veraison, and then increased sharply at veraison in berry skin and pulp. Anthocyanins in carpopodia and berry pedicels also increased sharply, although occurring later than in berry skin and pulp. Anthocyanins were high in young and senescing leaf lamina and low in expanding and mature lamina. Anthocyanins did not vary much in leaf vein and petiole tissue, or in bark, throughout the growing season.