含迟熟基因rin的番茄果实货架寿命相关性状的研究

分析比较了贮藏过程中的番茄成熟突变体rin材料L2与正常成熟番茄品种L5及其杂种一代L20果实的果实硬度、呼吸强度、番茄红素、贮藏指数及各种商品品质的差异。结果表明:番茄果实贮藏过程中果实硬度呈下降趋势;而果实的可溶性固形物、可溶性糖、Vc、番茄红素含量变化呈上升趋势,但是有机酸含量变化总体上呈现下降趋势,因此果实的糖酸比呈上升趋势;呼吸高峰的出现有很大的差异,L2的波动较小,且呼吸强度一直处于最低状态;rin番茄果实的贮藏指数最高,达到75%以上,而正常成熟的番茄贮藏指数最低,仅60%左右,含迟熟基因的品种与正常品种杂交后贮藏性显著下降,但比正常成熟番茄耐贮,贮藏指数比正常成熟的高约15%。     

番茄在非生物胁迫下实时定量RT-PCR中内参基因的筛选

近年来实时荧光定量PCR已经成为研究基因表达的标准方法,稳定的内参基因可使反应标准化进行,并提高该方法的敏感度和重复性。许多研究表明不同组织、细胞和不同条件下内参基因的表达存在很大差异,因此在研究基因表达分析时,需要以内参基因对目标基因的表达量进行校准,由此来获得更为准确的结果。本研究以番茄经过果糖、蔗糖、葡萄糖、高温和低温处理的材料为研究对象,利用实时荧光定量PCR方法,对Actin、CAC、TIP41、Expressed、SAND 5个内参基因m RNA水平的表达量进行分析。经ge Norm和Norm Finder软件分析5个内参基因的表达稳定性,以期为番茄果实基因表达调控相关的研究提供内参基因。研究结果为番茄植株在非生物胁迫下的实时定量RT-PCR分析中内参基因的选择提供了理论与实验依据。     

番茄SlETR6基因的克隆及非生物胁迫下的表达分析

为解析番茄乙烯受体基因SlETR6在非生物胁迫过程中的功能。以番茄为材料,克隆了番茄SlETR6基因,利用MEGA 5. 0软件对SlETR6基因编码的蛋白进行了聚类分析,并利用实时荧光定量PCR分析了SlETR6基因在番茄根、叶、花、果实不同发育时期的组织表达情况及对其在高盐、高温(40℃)、低温(4℃)、干旱胁迫条件下的表达模式。结果表明,SlETR6基因开放阅读框(Open reading frame,ORF)为2 265 bp,编码754个氨基酸,蛋白质分子质量为85. 05 ku,等电点为7. 28,与马铃薯St ETR-like蛋白的同源性最高;启动子分析显示,SlETR6基因含有热胁迫、干旱胁迫、低氧胁迫、光响应、乙烯、水杨酸及赤霉素应答等相关的顺式作用元件。实时荧光定量PCR分析表明,SlETR6在番茄不同组织中均有表达,且在花和转色期果实中有显著高表达。高盐胁迫6 h后,SlETR6基因呈现上调表达,12 h后达到峰值,而后回复正常表达水平;高温胁迫后,SlETR6基因表达量有明显的上升趋势;干旱胁迫早期SlETR6基因应答强烈,在胁迫处理1 h后表达量达到峰值。因此,推测SlETR6基因可能在番茄适应高盐、高温、干旱等逆境胁迫过程中发挥重要作用,可能参与番茄生长发育过程中的逆境调控。为番茄抗逆研究提供了新的候选基因资源。     

辣椒CaWRKY30转录因子的克隆、亚细胞定位及番茄斑萎病毒侵染下的表达分析

为研究辣椒CaWRKY30转录因子与番茄斑萎病毒互作的响应机制,以辣椒湘研11为试验材料,通过RNA提取、RT-PCR、切胶纯化及克隆等试验获得CaWRKY30编码序列。生物信息学分析结果表明,CaWRKY30全长1 122 bp,编码373个氨基酸,该基因编码的蛋白含有1个WRKY保守结构域和1个C₂H₂结构域,属于典型的Ⅱ（e）亚家族成员。系统发育分析表明,与马铃薯StWRKY22氨基酸序列的亲缘关系最近。本氏烟叶片亚细胞定位试验发现,CaWRKY30在本氏烟幼苗中定位于细胞核和细胞膜,并且导致细胞膜加厚。实时荧光定量PCR分析结果表明,观察番茄斑萎病毒机械摩擦接种辣椒后的病毒积累量,发现病毒积累量在接种1～14 d逐渐上升,在接种后14 d处于最大值,接种14 d后病毒积累量逐渐下降;同时,CaWRKY30受番茄斑萎病毒接种后诱导,在接种病毒1～14 d CaWRKY30表达量上调,14 d达到峰值,14 d以后表达量逐渐下降。综上,获得了CaWKRY30转录因子基因序列,该转录因子定位于细胞核和细胞膜,并初步阐述了辣椒CaWRKY30...     

番茄转录因子LeMADS-MC正反义植物表达载体的构建

为进一步阐明转录因子家族MADS-Box对番茄果实成熟的调控途径,本研究利用聚合酶链式反应技术(PCR)从番茄(Solanum lycopersicum)cDNA中克隆LeMADS-MC基因和LeMADS-antiMC基因核心片段,将这2个基因通过酶切分别正向连接到pCAMBIA1300-221载体和反向连接到pCXSN载体中,并用冻融法将重组载体导入农杆菌中。获得的重组载体分别通过PCR及酶切鉴定符合预期结果且测序结果与NCBI同源性高达100%。结果成功构建了适合于番茄农杆菌遗传转化的植物表达载体,为下一步通过LeMADS-MC基因研究果实成熟衰老机理奠定了物质基础。     

酸性转化酶基因家族在番茄果实发育及逆境胁迫下的表达分析

以普通栽培番茄(Lycopersicon esculentum)品种桃太郎为试材,通过半定量RT-PCR方法研究了5个转化酶基因在果实不同发育阶段不同部位的表达,并进一步研究了苗期番茄在亚高温、亚低温、NaCl盐胁迫和渗透胁迫下转化酶基因的表达变化.结果表明:果实膨大期主要受Lin5、Lin6和Lin8表达的调控;绿熟期仅有Lin8在发挥作用,而在果实完熟期Lin6、Lin8和AI2的表达明显.这说明在番茄果实发育的不同时期及果实的不同发育部位都受到酸性转化酶基因家族的不同成员的共同调控.亚适温对AI2的影响最明显,无论是亚低温还是亚高温,均能明显抑制AI2的基因表达;而对细胞壁束缚性的转化酶(Lin5、Lin6、Lin7)的表达影响不明显,对Lin8有明显的抑制作用.Lin5和Lin7在渗透胁迫和盐胁迫下均不表达,Lin6和Lin8的表达受盐胁迫和渗透胁迫的抑制,处理3d时表达变弱,处理5d后则完全抑制;AI2对渗透胁迫较敏感,处理3d其表达完全受抑制,而盐胁迫随处理时间的延长,表达逐渐变弱,直至完全消失.     

番茄SlUDP基因的克隆及其在镉、干旱和盐胁迫中的响应分析

非生物胁迫环境严重制约了番茄的生产,因此挖掘番茄耐非生物胁迫相关基因尤为重要。前期通过高通量测序筛选获得的UDP-糖基转移酶基因能够参与番茄镉胁迫应答反应,以番茄为试材,进一步研究该基因参与番茄抗逆的功能。首先,利用同源克隆法获得UDP全长的cDNA序列,对该序列进行生物信息学分析,再利用系统进化树分析该蛋白与其他植物的亲缘关系。其次,采用实时荧光定量PCR分析该基因的组织表达特性及其在3种不同非生物胁迫条件下(Cd、PEG-6000、NaCl)的表达模式。进一步利用转基因酵母分析胁迫表型。测序结果显示,该基因的cDNA全长为1 486 bp,包含一个1 452 bp的开放阅读框(ORF),编码483个氨基酸,将其命名为SlUDP。系统进化树分析结果显示该蛋白与马铃薯的亲缘关系最近。实时荧光定量PCR分析结果表明,该基因在番茄不同组织中存在表达差异,在叶中表达量最高,各部位的表达量为叶片果实根部侧茎主茎花。转SlUDP基因酵母胁迫表型分析结果显示,该基因提高了酵母对Cd及干旱的耐受性。根据以上结果推测SlUDP可能在番茄响应重金属镉和干旱胁迫中起到了一定的作用。     

果实特异启动子调控薄皮甜瓜ACC合成酶反义基因植物表达载体的构建

从成熟的薄皮甜瓜(齐甜1号)果肉组织中提取总DNA,经PCR扩增得到约0.5kb的ACC合成酶基因的片段,将其克隆到质粒载体pMD18-T中,测序表明,该基因为583bp,编码194个氨基酸;从番茄(东农706)叶片组织中提取总DNA,经PCR扩增得到约2.2kb的E8基因片段,将其克隆到质粒载体pGEM-TEasy中,测序表明,该基因为2192bp;以pCAM2301为起始植物表达载体,pCAM-GT为中间载体,成功构建了果实特异启动子(E8)调控薄皮甜瓜ACC合成酶反义基因植物表达载体,采用冻融法将其转入根癌农杆菌LBA4404,得到了完整的Ti质粒表达载体系统。     

番茄果实成熟软化过程中细胞壁作用机制研究进展

番茄是研究果实成熟的重要模式作物,细胞壁结构和成分的改变是造成果实成熟变软的重要因素,综述了果实成熟过程中细胞壁各种相关基因、酶和转录因子的功能和研究进展,旨在构建番茄果实成熟软化中的细胞壁作用机制相关调控网络,为增强果实耐贮性方面的相关研究提供参考.     

番茄不同截短U3启动子的克隆及功能分析

从中蔬四号番茄品种中克隆能在番茄叶片中高效转录的SlU3启动子,为今后利用CRISPR/Cas9基因编辑技术进行分子育种奠定了基础。采用2轮PCR的方法,第1轮PCR从中蔬四号番茄品种中克隆了3种SlU3启动子,再采用Transfer PCR方法分别对3个启动子进行截短,共得到6个不同长度的启动子,并分别构建6个截短的SlU3启动子驱动GUS融合植物表达载体,利用农杆菌转化法分别转染番茄叶片。运用DNAMAN软件对已克隆的SlU3和拟南芥AtU3启动子序列具有转录功能的必要元件进行序列分析;经过2轮PCR,首先从中蔬四号番茄品种中克隆了3种SlU3-1P、SlU3-3P、SlU3-4P启动子,其长度分别是1 156,1 114,1 147 bp,再采用Transfer PCR方法分别对3个启动子进行截短,共得到6个不同长度的启动子,其长度依次是489,318,450,248,457,248 bp,并分别构建6个截短SlU3启动子驱动GUS融合植物表达载体,启动子序列比对分析发现,番茄U3启动子与拟南芥U3启动子一样,也含有比较保守的2个元件,USE和TATA框,2个元件之间的位置比较固定。利用农杆菌转化法分别转染番茄叶片,结果显示,成功侵染后的番茄叶片均被染成蓝色,表明已克隆的6种不同截短番茄SlU3启动子均具有转录活性。成功克隆了6种在番茄叶片中高效转录的SlU3启动子,为构建番茄CRISPR/Cas9基因编辑载体提供更多高效的内源启动子。     

Mode of action of nitric oxide in inhibiting ethylene biosynthesis and fruit softening during ripening and cool storage of ‘Kensington Pride’ mango

The mode of action of nitric oxide (NO) in inhibiting ethylene biosynthesis and fruit softening during ripening and cool storage of mango fruit was investigated. Hard mature green mango (Mangifera indica L. cv. ‘Kensington Pride’) fruit were fumigated with 20 μL L⁻¹ NO for 2 h at 21 °C and allowed to ripen at 21 ± 1 °C for 10 d, or stored at 13 ± 1 °C for 21 d. During ripening and cool storage, ethylene production and respiration rate from whole fruit were determined daily. The 1-aminocyclopropane-1-carboxylic acid (ACC) content, activities of ACC synthase (ACS), ACC oxidase (ACO), and fruit softening enzymes such as pectin esterase (PE), endo-1,4-β-d-glucanase (EGase), exo- and endo-polygalacturonase (exo-PG, endo-PG) as well as firmness and rheological properties of pulp were determined at two- and seven-day intervals during ripening and cool storage, respectively. NO fumigation inhibited ethylene biosynthesis and respiration rate, and maintained higher pulp firmness, springiness, cohesiveness, chewiness, adhesiveness, and stiffness. NO-fumigated fruit during cool storage and ripening had lower ACC contents through inhibiting the activities of both ACS and ACO in the fruit pulp. NO-fumigated fruit showed decreased activities of exo-PG, endo-PG, EGase, but maintained higher PE activity in pulp tissues during ripening and cool storage. In conclusion, NO fumigation inhibited ethylene biosynthesis through inhibition of ACS and ACO activities leading to reduced ACC content in the fruit pulp which consequently, reduced the activities of fruit softening enzymes during ripening and cool storage.     

The manipulation and modification of tomato fruit ripening by expression of antisense RNA in transgenic plants

Summary The common cultivated tomato (Lycopersicon esculentum Mill.) provides a major focus for improvement of crop quality through genetic engineering. Identification of ripening-related cDNAs has enabled the modification of specific aspects of ripening by manipulating gene expression in transgenic plants. By utilizing antisense RNA to modify expression of ripening genes, we have inhibited the production of the cell wall-metabolising enzymes polygalacturonase and pectinesterase and created transgenic plants that contain, effectively, single, targeted mutations affecting these genes. Furthermore, this approach has been used with previously unidentified cDNA clones to enable both functional identification and manipulation of genes involved in ethylene production (ACC oxidase) and carotenoid biosynthesis (phytoene synthase). The use of antisense RNA targeted to specific genes to alter ripening phenotypes and improve commercial utility of fruit by affecting shelf-life, processing characteristics and nutritional content is discussed.We have used the extreme ripening-impaired mutant, ripening inhibitor (rin) to identify additional genes implicated in the ripening process. This approach has resulted in the cloning of several novel ripening-related mRNAs which are now being studied by antisense experiments. This may enable identification and manipulation of additional genes involved in processes such as softening, flavour and aroma generation and susceptibility to pathogens.Abbreviations ACC 1-aminocyclopropane-1-carboxylic acid - PE pectinesterase - PG polygalacturonase - SAM S-adenosyl methionine - SARs scaffold attachment regions     

Control of ripening in transgenic tomatoes

Major progress has been made over the last few years in the identification and regulation of tomato ripening genes. At least 25 genes showing elevated expression during ripening have been cloned and several, including polygalacturonase, which modifies fruit textures, have been shown to be ripening-specific. In addition, genes have been cloned for ACC synthase and ACC oxidase, which control the synthesis of ethylene, which plays a critical role in ripening. Inhibition of expression of polygalacturonase, pectinesterase, ACC synthase, ACC oxidase and phytoene synthase has been achieved in transgenic plants, using antisense technology. The expression of several genes has also been inhibited by sense gene suppression. New traits caused by these transgenes are stably inherited. Antisense tomatoes with reduced polygalacturonase have improved textural qualities which are being exploited commercially for the fresh and processed markets. Overexpression of phytoene synthase has been shown to restore carotenoid production in the yellow flesh mutant and can be used to enhance colour in other cultivars. Antisense fruit in which ACC synthase or ACC oxidase are inhibited show slower ripening and reduced over-ripening. ACC oxidase antisense genes have also been shown to delay leaf senescence. It is to be expected that further genes determining other quality traits will be identified and manipulated soon.     

Ethylene biosynthesis in apricot: Identification of a ripening-related 1-aminocyclopropane-1-carboxylic acid synthase (ACS) gene

Apricots are climacteric fruits with a high susceptibility to flesh softening and loss of flavor during postharvest storage, and most of the ripening processes are regulated by ethylene, which also has an effect on its own biosynthesis. To understand this process in apricot, inhibition of ethylene biosynthesis and perception was performed for studying key genes involved in the ethylene biosynthetic pathway. Apricots, cv. “Patterson”, were harvested with yellow-green ground color and immediately treated with either the ethylene perception inhibitor 1-methyl cyclopropene (1-MCP) at 10 μL L⁻¹ or the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG) at 1 g L⁻¹. After treatment, quality and physiological attributes such as firmness, color, total soluble solids, acidity, fruit weight, ethylene production and respiration rates were evaluated every 2 d until they ripened at 20 °C. Gene expression analysis was performed by quantitative polymerase chain reaction (qPCR). Both ethylene inhibitors were effective in reducing ethylene production, respiration rate and fruit softening. Three 1-aminocyclopropane-1-carboxylic-acid synthase (ACS) genes were characterized, but only the expression of ACS2 was highly reduced by ethylene inhibition, suggesting a key role in ethylene synthesis at ripening. Contrarily, ACS1 and ACS3 showed a higher expression under ethylene inhibition suggesting that the corresponding genes are individually regulated in a specific mode as observed in other climacteric fruits. Finally, changes in 1-aminocyclopropane-1-carboxylic-acid oxidase genes did not show a consistent pattern of ethylene modulation.     

桑树EIN2基因的分离与表达

EIN2是植物体内乙烯信号转导的中心元件,负责将乙烯信号由内质网传递到细胞核中。本文通过检索桑树基因组数据,获得一个EIN2候选基因(MaEIN2),并进行生物信息学分析和表达分析。该MaEIN2全长5614 bp,由7个外显子和6个内含子组成,包含3921 bp的CDS,编码1036个氨基酸残基。MaEIN2在进化树中与草莓、桃树等双子叶植物的EIN2蛋白关系较近,与单子叶植物关系较远。MaEIN2在老叶和成熟果实中的表达量分别高于在幼叶和幼果中,且随果实发育呈逐渐上升趋势,MaEIN2可能与器官的成熟衰老有关。选用乙烯利、ABA和NaCl处理桑树种苗,乙烯利能够促进MaEIN2的表达,而ABA和NaCl抑制MaEIN2的表达。本文为深入研究MaEIN2基因的功能奠定了基础。     

1-MCP对外源乙烯诱导油桃果实软化的影响

以秦光油桃为试材,研究了1-MCP处理对外源乙烯诱导果实软化的影响.结果表明,1-MCP处理可抑制外源乙烯诱导果实硬度的下降,将乙烯诱导果实的淀粉、纤维素和果胶类物质的降解延迟2天,对引起这些物质降解的相关酶类如淀粉酶、纤维素酶和多聚半乳糖醛酸酶(PG)等酶活性高峰的到来推迟2天,同时降低了多聚半乳糖醛酸酶(PG)活性高峰值.