利用蛋白质组学研究水果采后成熟的分子机理

果实成熟是发生在高等植物中复杂而有序的过程,由于植物种类和环境条件的不同,果实从不成熟到发育成熟过程包括了众多阶段。近年来,植物本身的生理过程与农业产业息息相关,继而影响经济效益,因此果实成熟过程的研究日益重要。果实成熟过程中,伴随着不同色素水平变化和糖等物质含量增加,果实色泽发生变化,大量生理代谢过程例如颜色、质地、风味和香气等受到外因(光照、温度)和内因(发育相关基因和激素)调控而发生变化。因而利用差异蛋白质组学方法系统研究果实从未成熟到成熟的不同生理过程和阶段分子水平上的动态变化具有十分重要的意义。到目前为止,一些重要果实及其不同发育和成熟过程的蛋白质组数据库日益完善和更新。     

Pericarp total protein profiles as molecular markers of tomato fruit quality traits in two segregating populations

The tomato fruit quality results of biochemical and physiological changes that occur during the ripening process. Although, the pericarp total protein profiles are less polymorphic than DNA-based markers the polymorphism in those could be directly associated with fruit quality traits. The aim of this work was to identify associations between polymorphic polypeptides from fruit pericarp at two ripening stages and fruit quality traits evaluated in two segregating populations of tomato. A cross between a normal ripening cultivar of Solanum lycopersicum (C, Caimanta) and a genotype carrying the nor (non ripening) gene (N) as well as a cross between Caimanta and a cherry type tomato of S. lycopersicum var. cerasiforme (Ce) showed genetic variance for several fruit quality traits such as fruit weight, shape, solids soluble content, acidity, color and fruit shelf life. The quantitative variations observed at phenotypic level had correspondence with the polymorphism detected in the protein profiles. Indeed, the polymophic polypeptides associated with quality fruit traits and fruit shelf life would be useful to assist tomato breeding programs as protein molecular markers.     

新疆杏果实发育过程中香气物质的变化及其特征成分的确定

以5个新疆主栽杏品种不同发育阶段的果皮和果肉为试验材料,使用GC–MS法检测分析其香气物质,共检测到154种香气物质,其中58种含量较为丰富。成熟期对果实香气物质的组成与含量有显著影响。随果实发育,芳樟醇、α–萜品醇、香叶醇、β–月桂烯、罗勒烯、2–己烯醇、苯乙醛和己醛的含量均迅速下降,而β–紫罗兰酮、香叶基丙酮、γ–癸内酯、δ–癸内酯和γ–十二内酯的含量迅速增加。果实发育前期以积累醇类、醛类、萜类和萜烯类为主,果实成熟过程中以积累酮类和内酯为主。果皮中萜类、萜烯类、醇、醛和内酯的含量均显著高于果肉中,而酮类物质的含量却显著低于果肉中。基于风味阈值法,共鉴别出新疆杏果实特征香气成分22种,其中芳樟醇、γ–癸内酯、δ–十二内酯、β–大马酮、顺,反–2,6–壬烯醛、苯乙醛、己醛、α–萜品醇、乙酸己酯、香叶醇和β–月桂烯等的贡献最大。     

Quality and volatile attributes of attached and detached ‘Pluk Mai Lie’ papaya during fruit ripening

The ‘Pluk Mai Lie’ papaya (Carica papaya L.) is a promising cultivated fruit for use in fresh and processed products due to its firm flesh, but the aroma it releases is flat. Changes in quality and volatile profiles were analyzed during on- and off-tree fruit ripening. Detached fruit ripened faster than attached fruit, accumulating high internal ethylene levels. Aside from peel color, which was redder in on-tree ripened fruit, most quality attributes changed similarly in the two ripening situations. A slight increase in total soluble solids (TSS) was measured from the onset of the preclimacteric stage, whereas titratable acidity (TA) remained stable throughout the development. Whereas 2-ethyl-1-hexanol was found specifically in green fruit, ethyl octanoate emerged only in fully-ripe fruit. Furthermore, benzyl isothiocyanate was the most abundant volatile and was present in fruit at every stage except full ripening. The production of total esters, highly correlated with a loss of firmness and an increase in cavity ethylene accumulation, was about 10-fold higher in off-tree ripened fruit. The levels of methanol and ethanol sources in fruit increased steadily throughout ripening, with esters formed from ethyl alcohol predominating from the half-ripe through the senescence phases. The alcohol dehydrogenase activity in the mesocarp increased dramatically during the early ripening stages, whereas alcohol acetyltransferase was active throughout ripening. No difference in volatile profiles was found in the papaya fruit during on-tree and postharvest ripening.     

杏果实香气物质的研究进展

果实香气是杏果实内在品质的一个重要特征。该文介绍了杏果实香气物质的检测方法,香气物质种类与组成,以及主要特征香气物质;综述了杏果实香气物质的生物合成途径与果实成熟过程中香气品质形成的影响因素,并提出对杏果实香气品质改良的研究方向。     

基于蛋白质组学研究光质对番茄果实挥发性物质的影响机理

以‘Micro-Tom’番茄(Solanum lycopersicum L.)为试材,种子发芽后30d移入人工气候室,分别进行红/蓝光组合(1:1、3:1、5:1、7:1)处理,以白光处理为对照。在番茄果实绿熟期、转色期、成熟期取样,测定果实挥发性物质含量及蛋白组数据。结果表明,在转色期和成熟期,对番茄风味有积极作用的己醛、反式–2–己烯醛、β–紫罗兰酮、牻牛儿丙酮、6–甲基–5–庚烯–2–酮、2–苯乙醇、愈伤木酚的含量在红/蓝光3︰1组合处理中最高,而对风味有消极作用的水杨酸甲酯的含量较低,并且在成熟期为0。进一步分析了红/蓝光3︰1组合处理与对照相比的差异蛋白,在成熟过程中番茄果实共鉴定到12个与挥发性物质产生有关的差异蛋白,其中8个上调表达,4个下调表达。通过对12个差异蛋白进行mRNA水平的验证发现,只有转色期的苯丙酮酸互变异构酶(MIF)在蛋白质和mRNA水平表达不一致,其他11个蛋白在两个水平表达均一致。     

Precursor uptake assays and metabolic analyses in isolated tomato fruit chromoplasts

Background  

Carotenoids are the most widespread group of pigments found in nature. In addition to their role in the physiology of the plant, carotenoids also have nutritional relevance as their incorporation in the human diet provides health benefits. In non-photosynthetic tissues, carotenoids are synthesized and stored in specialized plastids called chromoplasts. At present very little is known about the origin of the metabolic precursors and cofactors required to sustain the high rate of carotenoid biosynthesis in these plastids. Recent proteomic data have revealed a number of biochemical and metabolic processes potentially operating in fruit chromoplasts. However, considering that chloroplast to chromoplast differentiation is a very rapid process during fruit ripening, there is the possibility that some of the proteins identified in the proteomic analysis could represent remnants no longer having a functional role in chromoplasts. Therefore, experimental validation is necessary to prove whether these predicted processes are actually operative in chromoplasts.     

Cloning and expression analysis of three genes encoding ubiquitins in papaya (Carica papaya L.)

Papaya (Carica papaya L.) fruit have a short shelf-life due to rapid ripening induced by ethylene, which usually results in a high percentage of product loss. However, little is known about the genetic mechanism of ripening and the attributes of fruit quality. Ubiquitin (UBQ) proteins have received increasing attention because they play important roles in response to ripening and in regulating certain developmental processes in plants. In the present study, three genes encoding UBQ proteins, CpUBI1, CpUBI2, and CpUBI3, were isolated from papaya fruit. The lengths of the cDNAs of CpUBI1, CpUBI2, and CpUBI3 were 1,485 bp, 1,642 bp, and 529 bp, encoding 306, 308, and 156 predicted amino acids, respectively. Sequence analysis demonstrated that the CpUBI1 and CpUBI2 proteins contained four consecutive structural domains of the UBQ superfamily, while CpUBI3 contained a ribosomal domain structure of the S27a superfamily. RT-qPCR analysis demonstrated that ethephon treatment increased CpUBI gene expression significantly, compared to 1-methylcyclopropene (1-MCP) treatment and the untreated controls. Levels of CpUBI1 and CpUBI2 gene expression were significantly higher than CpUBI3. These results suggested that CpUBI1, CpUBI2, and CpUBI3 might have different roles during papaya fruit ripening and softening.     

草莓果实发育过程中糖代谢相关基因的表达分析

 为了分析草莓（Fragaria × ananassa Duch.）果实发育过程中可溶性糖积累与相关基因表达量的关系,以‘杜克拉’草莓7个发育时期的果实为试材,利用实时荧光定量RT-PCR的方法,分析果实发育中蔗糖转运蛋白及糖代谢关键酶（酸性转化酶、蔗糖合成酶和蔗糖磷酸合成酶）4个基因的表达量以及可溶性糖含量的变化趋势。结果表明,蔗糖、葡萄糖和果糖含量随着果实发育都呈逐渐增加的趋势,尤其蔗糖积累与果实成熟的关系较密切。随着果实发育,蔗糖磷酸合成酶基因表达量呈逐渐增加的趋势,尤其在果实发育的后期增加较快;蔗糖合成酶和酸性转化酶基因表达量除了白熟期和转色期外,呈逐渐降低的趋势;蔗糖转运蛋白基因表达量呈先升后降,降后又升的变化趋势,尤其在白熟期前急剧增加。结合可溶性糖和基因变化趋势分析表明,蔗糖转运蛋白和蔗糖磷酸合成酶在草莓果实发育过程中发挥着重要的作用。     

Methyl jasmonate plays a role in fruit ripening of ‘Pajaro’ strawberry through stimulation of ethylene biosynthesis

The role of methyl jasmonate (MJ) in strawberry (Fragaria × ananassa Duch. cv Pajaro) fruit ripening was investigated by monitoring its endogenous concentrations in fruit at various stages of development and the effects of exogenously applied MJ at these stages on ethylene biosynthesis. The concentration of endogenous trans-MJ was significantly higher in the white fruit (31.7–162.2 ng g⁻¹) and decreased sharply in half and fully ripe fruit. Higher concentrations of endogenous trans-MJ at the white stage of strawberry fruit development followed by a decline during fruit ripening indicate that MJ may play an important role in modulating fruit ripening. Significantly increased ethylene production was measured in the fruit when MJ was applied at white, half ripe and at fully ripe stage. The application of MJ (50 μM) resulted in significantly highest ethylene production and increased activities of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase as compared to all other treatments. The effect of exogenously applied MJ on ethylene production, ACC synthase and ACC oxidase activities was dependent on concentration of MJ applied and on fruit developmental stage. In conclusion, MJ in strawberry modulates fruit ripening, as its concentration is higher in white fruit and is declined with the progression of ripening and exogenous application of MJ increases ethylene production, activities of ACC oxidase and ACC synthase depending upon the concentration of MJ applied and fruit developmental stage.     

Developmental and tissue-specific changes in oxidative parameters and antioxidant systems in tomato fruits grown under salt stress

In tomato plants, salt stress has been induced to improve the quality of fruit. In general, plants under salt stress produce reactive oxygen species (ROS). Plants have their own ROS scavenging systems (antioxidant systems). In tomato plants, salt-induced changes in antioxidant systems have been examined extensively in leaves and roots; however, detailed information about salt-stressed fruits is not available. We examined the salt-induced changes in the antioxidant systems of the pericarp (containing epidermis) and pulp (containing seeds, placenta, and locule) during fruit ripening. Salt treatments were applied by adding 100 mM NaCl to the nutrient solution. In the pericarp and pulp, lipid peroxidation and hydrogen peroxide content were not increased by salt stress during ripening, indicating the absence of salt-induced oxidative stress. In the pericarp, the activities of superoxide dismutase (EC 1.15.1.1) and ascorbate (ASA)–glutathione (GSH) cycle-related enzymes increased with salt stress at the turning stage. Thus, at the turning stage, the antioxidant system may contribute to the enzymatic reaction involved ASA–GSH cycle. However, during the red and over-ripe fruit stages, salt stress produces little effect on antioxidant enzymes. In addition, the concentrations of antioxidants, such as the reduced form of ASA and GSH, increased during ripening in the control fruit, but those in the salt-stressed fruit remained unchanged. Therefore, the antioxidant system may contribute to the nonenzymatic reactions such as ASA and GSH taking place during the red and over-ripe fruit stages. In contrast, in the pulp, salt stress produces little effect on antioxidants and antioxidant enzymes. These results indicate that the salt-stressed fruit has protection mechanisms against salt-induced oxidative stress during ripening in both the pericarp and pulp. Salt-induced changes in antioxidant systems differed between the pericarp and pulp.     

Fruit Quality and Antioxidant Properties in Alabama-Grown Blackberries During Fruit Maturation

Abstract

Changes in fruit quality attributes and antioxidative properties from six cultivars of thornless blackberries (Rubus sp.) (‘Apache’, ‘Arapaho’, ‘Chester’, ‘Loch Ness’, ‘Navaho’, and ‘Triple Crown’) during four different ripening stages (red, motded, shiny-black, and dull-black) were determined under Alabama growing conditions. Berry fruit samples were evaluated for pH, titratable acidity, total soluble solids, TSS/TA ratio, soluble sugars, vitamin C (reduced, oxidized, and total) and antioxidant capacity (measured as trolox equivalent antioxidant capacity, TEAC). Significant variation among cultivars and maturity of harvest were in fruit quality attributes and antioxidative properties found. An increase in fruit pH concomitant with a decline in titratable acidity (TA) was observed during ripening for all cultivars. Total soluble solids (TSS) values increased from 5.7 to 11.6%, and TSS/TA ratio ranged from 11.9 to 63.6. Highest reducing and total sugar content were contained in dull-black fruit. Vitamin C content either declined or remained unchanged with ripening and the pattern was dependent on cultivar, maturity at harvest. In general, antioxidant activity declined between red and dull-black ripening stages. The results indicate that TSS/TA ratio and TEAC were good indicators of fruit maturity and nutritional quality, respectively.     

黄肉苹果转色期前后类胡萝卜素合成相关差异表达基因鉴定

为了了解黄肉苹果种质成熟时富集类胡萝卜素的分子机制,以黄肉种质‘东北黄海棠’为材料,选择转色期前后(盛花后90 d和115 d)两个发育时期的果实进行RNA-seq测序,分析两个样本差异表达基因,并利用实时荧光定量PCR技术验证获得的类胡萝卜素合成相关差异表达基因的表达水平。结果获得两个样本显著差异表达基因共3 056个,与盛花后90 d果实比较,成熟期果实中有1 270个基因上调表达,1 786个基因下调表达。对这些表达差异基因进行了Pathway富集分析,结果显示差异表达基因涉及类胡萝卜素、苯丙氨酸以及类黄酮等代谢途径,其中类胡萝卜素代谢途径基因有3个上调,4个下调。通过对这7个差异表达基因进一步的qRT-PCR及聚类分析,发现一个新的候选基因MdCCD4b,该基因与菊花以及桃等CCD4聚为一类,与其他作物功能已知的CCD4一样,其表达水平与黄肉种质中类胡萝卜素积累呈负相关,推测黄肉种质果实成熟后类胡萝卜素的富集与MdCCD4b基因显著下调有关。     

Effects of post-harvest calcium chloride or salicylic acid treatments on the shelf-life and quality of apricot fruit

Summary

The purpose of this work was to estimate the effects of post-harvest calcium chloride or salicylic acid treatments on the physicochemical characteristics and shelf-life of apricot (Prunus armeniaca L.) ‘Asgar-Abad’ fruit stored at 1ºC in a normal atmosphere for 21 d after harvest. Fruit were dipped in deionised water (control), or in 40, 60, or 80 mM CaCl₂, or in 1.0, 2.0, or 3.0 mM salicylic acid (SA) for 10 min.Total soluble solids (TSS) contents, titratable acidity (TA), ascorbic acid contents, total phenolics contents, and total anti-oxidant activity were determined 7, 14, or 21 d after each treatment. Fresh weight (FW) loss, titratable acidity, and TSS contents were improved by all treatments. Fruit treated with 3 mM SA exhibited the highest phenolics content during the storage period. At the end of the storage period, the highest values of TSS were observed in the 2.0 mM and 3.0 mM SA treatments. This experiment revealed that post-harvest treatment with SA or CaCl₂ prolonged the storage-life and preserved the valuable marketing characteristics of apricot fruit, presumably because of their inhibitory effects on fruit softening, ripening, and senescence. Over 21 d in cold storage, 2.0 mM SA was found to be the best treatment to maintain fruit quality in terms of FW loss, while 60 mM CaCl₂ was optimal for achieving high ascorbic acid concentrations and enhancing the anti-oxidant capacity of fruit.     

Changes in ripening behavior of ‘d'Anjou’ pears (Pyrus communis L.) after cold storage

‘d'Anjou’ pear fruit, harvested at optimum maturity with flesh firmness of 6.8 kg, were stored at ?1.1°C. Fruit were ripened at 20°C for 15 days following storage for 1–8 months. Dessert qualities were evaluated organoleptically on Day 10 of each ripening period. Changes in fruit firmness, extractable juice, titratable acids, solubl solids, respiration, ethylene production and internal ethylene were determined daily during each ripening period. Fruit firmness declined continually from 6.8 kg at harvest to 4.5 kg after 8 months of storage. Fruit stored for 2–8 months softened with a similar pattern during a 15-day ripening period at 20°C, while fruit stored for 1 month softened at a slower rate during ripening to 3.2 kg, with a coarse and dry texture after 15 days at 20°C. Fruit stored for 2–4 months ripened with the desirable buttery and juicy texture, while those stored for more than 5 months ripened with a coarse or mealy and dry texture. The buttery and juicy texture was highly correlated with a lower extractable juice, which could be used for quantitative determination of storage life based on ripened fruit quality. Changes in titratable acids and soluble solids during each ripening period were not associated with changes in dessert qualities of the ripened pears. Rates of respiration, ethylene production and internal ethylene during ripening at 20°C varied with duration of storage, but were not associated with changes in dessert qualities of the ripened fruit.     

胚培早熟杏新品种——新世纪

 ‘新世纪’杏是采用有性杂交(‘二花槽’ב红荷包’) 与胚培技术相结合育成的早熟新品种, 具有开花晚、成熟早、果实大、外观美、香味浓及品质优等特点, 适合华北地区大棚及露地栽培。     

Defense response of tomato fruit at different maturity stages to salicylic acid and ethephon

In order to elucidate whether fruit maturity stage influence the induced resistance of exogenous elicitors in tomato and the involved mechanisms, we investigated the defense responses of tomato fruits against Botrytis cinerea, ethylene production and internal quality following treatments of fruit with salicylic acid (SA) or ethephon (ET) at mature green (MG) and breaker (BR). SA significantly suppressed decay and disease incidence in tomato fruits at both MG and BR stages, along with higher expression level of PR1 gene after 2 days of treatment. All fruits treated by SA had lower contents of ethylene and lycopene. The ET-treated fruit at both maturity stages showed lower disease incidence and higher level of PR2 and PR3 expression compared with the control fruit. ET treatment significantly enhanced ethylene and lycopene contents, and accelerated fruit ripening. Our results suggest that SA and ET induced disease resistance in fruits by mediating the expression of different pathogenesis-related genes and have different effects on fruit ripening, which in turn influences the disease resistance of tomato fruits.