转录因子FabHLH148参与草莓果实的颜色发育

【目的】探究碱性螺旋-环-螺旋（basic helix-loop-helix,bHLH）转录因子在草莓果实成熟过程中的功能。【方法】基于转录组测序和基因组数据库,克隆FabHLH148基因;分析其理化性质、保守结构域、预测编码的蛋白质结构、系统进化树、亚细胞定位等;采用RT-qPCR检测其在草莓中的时空表达水平,并构建过表达（over expression,OE）和RNA干扰（RNA interference,RNAi）载体,利用农杆菌介导瞬时侵染草莓果实,观察记录表型,检测FabHLH148表达水平,并测定花色素苷含量。【结果】FabHLH148基因CDS区全长687 bp,编码228个氨基酸,预测蛋白分子质量24.89 ku,理论等电点（p I）为11.65;该基因属于bHLH超家族,因其与二倍体草莓FvbHLH148序列相似度最高,所以将其命名为FabHLH148;亚细胞定位显示,FabHLH148主要定位在细胞核。RT-qPCR结果表明,FabHLH148在草莓不同组织部位均有表达,在果实中有较高表达并随果实成熟表达量显著升高。过表达FabHLH148能够促进果实着色以及花色素...     

茶树低温胁迫转录因子CsICE的亚细胞定位及表达分析

 以茶树[Camellia sinensis（L.）O. Kuntze]品种‘迎霜’为试验材料,采用PCR技术扩增出与茶树低温胁迫相关转录因子CsICE的开放阅读框,长度783 bp。采用荧光定量PCR分析CsICE的表达量,结果表明CsICE在根、茎、叶、花和果中都有表达,在叶中表达量最高,是根、茎、果中表达量的4倍;在500 μmol ? L^-1 ABA处理下,幼叶中CsICE表达峰值是对照的40倍,在4 ℃低温处理下,最高值是对照的20倍,在10%聚乙二醇6000处理的干旱条件下表达量最高值只有对照的5倍。亚细胞定位结果显示CsICE定位在细胞核上。     

NAC转录因子在果实成熟中的调控作用

NAC转录因子是植物中最大的特异性转录因子家族之一,其依赖由高度保守的N端结构域和高度变异的C端转录调控结构域组成独特的NAC结构域发挥功能,在果实成熟的调控中发挥着重要的作用。在介绍NAC转录因子的结构特征及不同物种NAC基因的成员与分类的基础上,总结了近年来NAC转录因子在果实成熟过程中的积极作用,包括促进果实软化影响果实质地,促进叶绿素降解及类胡萝卜素、类黄酮和花色苷的合成决定果实着色、调控糖分积累影响果实糖酸比例以及促进多种芳香化合物合成积累形成果实特有风味、果实脱涩等方面,并阐述了NAC转录因子与内源激素特别是乙烯和ABA交互在调控果实成熟中的重要作用。总结了NAC转录因子调控果实成熟的潜在机制以及影响NAC表达的因素与分子通路,旨在为在果实成熟性状遗传改良与调控技术研发提供重要参考。     

番茄转录因子基因SlWRKY16的克隆及原核表达分析

从栽培番茄(Solanumlycopersicum)‘M82’中克隆到1个WRKY家族基因SlWRKY16。研究结果显示:SlWRKY16包含1 497 bp的完整开放读码框,编码498个氨基酸,理论分子量为55.5 kD,含有1个WRKYGQK保守结构域和C2H2锌指结构域,属于Ⅱb类WRKY转录因子基因,且定位于细胞膜上;栽培番茄Sl WRKY16与潘那利番茄Sp WRKY6(XP₀15064265.1)、马铃薯St WRKY6(XP₀06350473.1)同源性最高。qRT-PCR结果显示SlWRKY16在番茄不同组织中均有表达,叶片中的表达量最高;短时间非生物胁迫下该基因的表达量显著降低。此外,重组菌pET-30a-SlWRKY16在NaCl、甘露醇胁迫下生长均明显低于对照菌pET-30a。综上,番茄SlWRKY16基因可能在响应非生物胁迫过程中具有负调控效应。     

茶树低温胁迫转录因子 CsICE 的亚细胞定位及表达分析

以茶树[Camellia sinensis（L.）O. Kuntze]品种‘迎霜’为试验材料,采用 PCR 技术扩增出与茶树低温胁迫相关转录因子 CsICE 的开放阅读框,长度 783 bp。采用荧光定量 PCR 分析 CsICE 的表达量,结果表明 CsICE 在根、茎、叶、花和果中都有表达,在叶中表达量最高,是根、茎、果中表达量的 4 倍;在 500 μmol L-1ABA 处理下,幼叶中 CsICE 表达峰值是对照的 40 倍,在 4 ℃低温处理下,最高值是对照的 20 倍,在 10%聚乙二醇 6000 处理的干旱条件下表达量最高值只有对照的 5 倍。亚细胞定位结果显示 CsICE 定位在细胞核上。     

草莓果实成熟软化相关基因研究进展

对草莓果实细胞壁水解酶和伸展蛋白在成熟软化时的功能和作用进行了阐述,并对已报道的相关编码酶（或结构蛋 白）的基因进行了描述和评价。指出纤维素酶、果胶裂解酶和伸展蛋白是参与草莓果实成熟软化的关键因子;并提出利用RNA 干扰等生物技术对关键基因进行调控,降低相关酶的mRNA表达,提高草莓果实硬度的研究思路。     

葡萄果实成熟相关NAC转录因子的筛选、克隆及表达分析

【目的】NAC转录因子在植物生长发育中起重要调控作用。旨在筛选参与葡萄果实成熟的NAC转录因子,揭示NAC转录家族在葡萄果实成熟过程中的生物学功能。【方法】利用荧光定量PCR技术分析了NAC基因在葡萄果实不同时期的表达水平及其组织特异性,对候选基因的核苷酸序列、蛋白质性质进行分析。同时,构建pGBKT7重组质粒检测转录因子的自激活能力。【结果】红地球葡萄不同发育阶段的NAC基因表达分析中,筛选出11个差异表达的NAC基因。结合其在红巴拉多葡萄中的表达情况,确定4个NAC转录因子为候选基因。VvNAC5、VvNAC11、VvNAC13、VvNAC18基因的开放阅读框长度分别为1083、1092、1098、1062 bp,分别编码360、363、365、353个氨基酸,各蛋白分子质量与等电点不同。蛋白序列对比结果显示4个NAC基因在N端都包含高度保守的NAM结构域,但C端序列高度变异。系统进化树分析显示VvNAC5、VvNAC11、VvNAC13与众多参与组织形成和器官发育相关的NAC蛋白聚为一类,推测同时在组织形成发育过程中发挥作用;VvNAC18与众多调控果实成熟衰老及叶片脱落相关蛋白...     

柑橘响应溃疡病菌转录因子基因CsAP2-09的克隆与功能分析

对柑橘中AP2转录因子进行注释,并克隆柑橘溃疡病相关的Cs AP2-09,研究外源水杨酸、茉莉酸甲酯、乙烯利、机械损伤以及溃疡病菌对该基因的诱导表达,确定其表达模式。从柑橘全基因组公共数据库一共注释出12个AP2成员,据系统发育和结构可以将其分为4个亚类;可能与抗、感溃疡病相关的Cs AP2-09基因全长4 159 bp,开放阅读框1 467 bp,编码488个氨基酸,具有典型的AP2结构,同时也具有一些结构特殊性;该基因在细胞核中优势表达,与定位信号预测结果吻合;上游启动子元件含多个与植物逆境或激素应答相关的顺式作用元件,如BOX-W1、CGTCA-motif、TCA-element、WUN-motif等;诱导结果表明Cs AP2-09对外源水杨酸、茉莉酸甲酯、乙烯利及机械损伤均有响应;柑橘溃疡病菌侵染可诱导抗病品种四季橘中此基因明显上调表达,而在感病品种纽荷尔中变化趋势不显著。上述研究表明Cs AP2-09是一个响应溃疡病菌侵染的,可作为研究柑橘抗溃疡病的候选基因。目前已将其在锦橙中超表达,共筛选出8个转基因植株,后期将对其进行抗病性评价以确定其分子育种价值。     

NAC转录因子在果实发育成熟过程中的作用研究进展

就NAC基因结构与功能及对果实发育和成熟的调控作用研究进行了综述,提出NAC转录因子通过乙烯途径和多重激素途径影响果实成熟。乙烯途径包括：乙烯诱导NAC转录因子,NAC转录因子调控乙烯信号系统上游转录因子,和直接调控主要乙烯合成基因影响果实成熟;多重激素途径包括,通过生长素、脱落酸及赤霉素/油菜素内酯等途径,影响果实成熟。     

A critical path analysis of fruit production in strawberry

The method of Critical Path Analysis has been applied to strawberry fruit production from runner propagation to first harvest in an experimental situation. The quantitative components of yield and the stages of their creation have been identified and arranged in sequential order.Analysis of crop data showed that large variations in yield potential arose early in development, from causes not identified in the experiment. In the fruiting season there was a substantial shortfall in realisation of existing potential due to inefficient fertilisation of ovules and poor berry development.The analysis indicates three phases of development where factors not yet examined can have a large effect on yield.     

Size factors in strawberry fruit

Analysis of data relating to berries of 9 cultivars grown under different conditions indicates that the weight of ripe berries can be accounted for by the general equation

$\text{Berry fresh weight (g)}\text{=}\text{(}\text{Total no. of achenes}\text{? C)F}\text{(}\text{No. of achenes/cm}{}^2\text{of surface}\text{)}$

where C is a numerical adjustment probably due to the non-spherical shape of berries, and F is the weight in g per unit area of tissue which forms the berry, and both may be characteristic of each cultivar under normal conditions.The number of achenes on perfect berries, equal to the number of ovules initiated on the flowers, is closely related to the position of the flower on the inflorescence. Expressing Rank value on the scale 1 : $\text{1}\text{2}$ : $\text{1}\text{4}$ : $\text{1}\text{8}$ for Rank 1 : Rank 2 : Rank 3 : Rank 4, a general equation

$\text{Achene no.}\text{= (K ×}\text{Rank value}\text{) + D}$

can be applied to all cultivars, although K and D may vary between cultivars and to a less extent within a cultivar. If these size factors are in fact basically genetic, a grower may have little scope for influencing berry size except during berry development in the fruiting-season.     

脆肉梨果实成熟过程中质地性状的变化

【目的】探讨脆肉梨成熟过程中不同时期、果实不同部位质地性状的差异和变化规律。【方法】以脆肉梨品种‘华酥’和‘圆黄’为试材,采用食品物性分析仪质地多面分析法(TPA)和穿刺试验,测定果肉脆度、硬度、黏着性、弹性、胶黏性、咀嚼性和果皮硬度等7个质地性状。【结果】各质地性状在梨果实成熟过程中均发生显著变化,而且果实萼部、中部和梗部3个部位的质地性状均存在差异;除黏着性与其他参数间的相关性较差之外,果肉脆度、果肉硬度、弹性、胶黏性、咀嚼性和果皮硬度之间均呈极显著正相关。【结论】首次明确了在梨果实成熟过程中各部位质地性状的变化规律,可以为梨适宜采收成熟度的确定提供理论依据。     

The components of fruit size in strawberry

High Correlation coefficients have been found in the application of the formula:

$\text{Fresh weight of ripe berry}\text{(g)}\text{=}\text{(Total number of achenes?C)F}\text{(Number of achenes per cm}{}^2\text{of surface}$

to data for a large number of strawberries from nine cultivars. Of the terms in the equation (Total no. of achenes — C) was found to be different in different cultivars and to be related to the position of the berry on the inflorescence, but there was no constant relationship between the achene numbers in the different ranks of berry. Whether the numbers of achenes per berry can be altered by environmental or cultural treatments was not resolved. F, a term having the dimensions of weight per area, represents weight per unit area of berry surface and seems to be constant amongst plants of a cultivar subject to uniform treatment, but differs between cultivars and treatments.The number of achenes per cm² of surface on ripe berries is a measure of berry development in the fruiting season and may be affected by environmental and managerial factors and by internal competition between fruits and leaves on the same plant.The interactions of these factors on berry size enable two stages to be recognised at which size is determined, namely during flower formation, when achene numbers and possibly F are fixed, and during fruit development after pollination when the term for spatial distribution of achenes is settled.It is suggested that an examination of the effects of different treatments on each of the size components might enable a distinction to be drawn between the influence on yield of genetic characteristics on the one hand and intrinsically variable characteristics subject to external influence on the other hand, thus clarifying the type of research and/or development needed to enable growers to achieve maximum yields.     

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.     

果树EST在果实发育和成熟研究中的应用

表达序列标签(EST)已成为植物功能基因组学研究的重要手段,在揭示植物生长发育机制方面起着重要作用。近年来果树EST研究与应用也得到快速发展,dbEST数据库中EST信息量超过5 000条的果树已达37种。着重介绍柑橘、葡萄、苹果、猕猴桃、桃、草莓和杨梅等果树EST在果实发育和成熟研究中的应用进展,并展望今后研究的热点和趋势。     

Gibberellin-like substances during ripening of olive fruit

The activity of gibberellin-like substances in olive fruits, Olea europea L. cultivar ‘Manzanillo’, was investigated. A decrease in gibberellin activity was found with the transition from green ripe to black ripe; simultaneously, the activity of inhibiting substances was demonstrated. The general aspects of ripening and their reference to the specific processes taking place in the olive fruit are discussed.     

Physiological changes in boysenberry fruit during growth and ripening

Summary

Boysenberries (Rubus hybrid) were harvested at five developmental stages (green, “turning”, pink, red and purple) to study changes associated with flavour, colour and firmness, with a particular focus on the different enzymes involved in chlorophyll degradation or cell wall degradation. The level of reducing and non-reducing sugars increased 109- and 52-fold, respectively, between the “turning” and the purple stage. Titratable acidity increased by 84% between the green and the pink stage, but dropped by 41% between the red stage and full ripening. Total phenols displayed their highest values in green and “turning” fruit. Chlorophyll a and b degradation occurred mainly during the early stages of development, and was paralleled by a 2.3-fold increase in chlorophyllase activity and a 5-fold increase in Mg-dechelatase activity between the green and the red stages. Chlorophyll peroxidase activity was high at the green stage, but did not change significantly after the “turning” stage. This is the first report on the activity of chlorophyll-degrading enzymes in Rubus spp. fruits. Anthocyanins increased 11-fold between the “turning” and the pink stages, and an additional eight-fold between the pink and the purple stages. Fruit firmness decreased noticeably during ripening, with a concomitant 10.75-fold increase in polygalacturonase activity, beginning at the “turning” stage. Endo- -1,4-glucanase and -galactosidase activities rose 9.2- and 6.7-fold, respectively, after the pink stage and paralleled the major softening process taking place between the pink and purple stages, when fruit firmness decreased from 3.83 N to 0.29 N. Pectin methylesterase activity was high in pink and red fruit, but decreased by 21% as the fruit turned from red to purple. This is the first report on cell wall enzyme activities whose combined action might be required for the breakdown of natural cell wall substrates during ripening in boysenberry, as happens in other soft fruits.     

Heat treatments and expansin gene expression in strawberry fruit

Heat treatments have been applied in fruit postharvest technology for insect disinfestations, decay control, ripening delay and modification of fruit responses to other stresses. Heat treatment affects several aspects of fruit ripening, such as ethylene production and cell wall degradation probably through changes in gene expression and protein synthesis. In this paper, strawberries (Fragaria × ananassa Duch., cv Camarosa) at 50–75% red stage of ripening were heat-treated at 45 °C during 3 h in an air oven and then stored at 20 °C for 0, 4, 18, 24 and 48 h. Fruit firmness was determined and the expression of a set of expansin genes (FaEXP1, FaEXP2, FaEXP4, FaEXP5 and FaEXP6) was analyzed. The firmness of treated fruit was higher than that of control fruit 24 h after treatment, though the differences disappeared after 48 h at 20 °C. The analysis by northern-blot indicated that heat treatments affected differently the expression of expansin genes. The expression of FaEXP1, FaEXP2 and FaEXP6 was lower in treated fruit during the following 24 h post-treatment. The lower expression of these expansin genes could contribute to delay softening after heat treatment.