叶片喷施脱落酸对桃果实着色及相关基因表达的影响

以美香桃为试材,于果实着色前用25 mg/L 的脱落酸（ABA）溶液喷施叶片,研究了ABA 处理促进桃果皮着色的效果以及对果皮花色素苷合成相关基因表达的影响。结果表明,ABA 处理对果实单果重、 可溶性固形物含量和固酸比影响不显著, 但明显改善果实着色,果皮花色素苷含量增加了39.48%,果面光泽明亮度（L*值）和色调角（h*值）分别下降了6.86% 和18.64%,红绿色差指标（a*值）增大了134.19%。ABA 处理显著促进了查尔酮合成酶基因（CHS）的上调表达以及类黄酮葡萄糖苷转移酶基因（UFGT）、 二氢黄酮醇4-还原酶基因（DFR）、花色素合成酶基因（LDOX）的提前表达。据此推测,ABA可能参与了桃果实花色素苷合成的调控,对花色素苷合成具有促进作用。     

马铃薯愈伤组织中色素含量与4个花色苷合成相关基因的表达差异

本研究从马铃薯（Solanum tuberosum cv．Chieftain）茎的愈伤组织中分离得到绿色、白色和红色3种愈伤组织,并利用鲜重法和分光光度法分别测量愈伤组织的生长量、叶绿素和花色苷的含量;通过半定量RT—PCR法分析4个花色苷生物合成相关基因的表达差异。结果表明：绿色愈伤组织生长最快,叶绿素含量最高,红色愈伤组织生长最慢,叶绿素含量最低;绿色和白色愈伤组织中几乎不含花色苷,红色愈伤组织中花色苷含量最高,达2．1OD513/mgFw;对CHS、F3H、DFR和F3’5’H四个花色苷生物合成相关基因表达分析发现,绿色和白色愈伤组织不合成花色苷可能与DFR基因不表达有关。本实验结果为进一步阐明花色昔生物合成机理和花色苷色素的生产应用提供一定的理论依据。     

彩色油菜花瓣色素成分研究

为明确彩色油菜花瓣色素成分和色素呈色机制,提高彩色油菜育种效率,本研究比较了红色、橙色、黄色和白色4种色系共10种彩色油菜花瓣色素代谢的次生代谢物含量,并采用液质联用仪(HPLC-MS/MS)分析红色、橙色和黄色油菜花瓣中花青素和类胡萝卜素含量,同时对花青素合成关键酶活性和编码关键酶活性的基因表达量进行分析。结果表明,各色系油菜花瓣积累了大量酚类和类黄酮化合物。红色系和橙色系油菜花瓣中含有丰富的原花青素和花色苷;黄色系油菜花瓣中不含原花青素,但含花色苷;白色系油菜花瓣既不合成原花青素,也不合成花色苷。红色和橙色油菜花瓣中的花色苷主要成分是矢车菊素和芍药素。红色、橙色、黄色和白色油菜花瓣中均含有胡萝卜素和番茄红素,且4种花色花瓣中的番茄红素含量均高于胡萝卜素。红色、橙色和黄色油菜花瓣的番茄红素含量仅为对应花色花瓣花青素的0.25%、0.15%、0.02%。基因表达分析结果表明,引起花青素在不同色系油菜花瓣中积累差异的基因为二氢黄酮醇还原酶基因(DFR)和花青素还原酶基因(ANS),在红色、橙色和橙黄色花瓣中DFR和ANS的表达量分别为黄色花瓣的100倍和1 000倍以上。相关性分析表明,彩色油菜DFR和ANS基因的表达量与花色苷含量呈高度正相关性。但是,DFR和ANS活性在红色、橙色、黄色和白色油菜花瓣中差异不显著。本研究为彩色油菜进行基因操纵中靶基因的选择和合理的育种线路提供了理论基础。     

Storage temperature effects on blood orange fruit quality.

Orange fruits of two blood varieties (Tarocco and Moro) were stored at 8 degrees C and 22 degrees C for 85 and 106 days, respectively, and analyzed periodically for standard quality parameters (total soluble solids, total acidity, ascorbic acid, juice yield, and rind color) and sensory influencing parameters (anthocyanins, and total and free hydroxycinnamic acids). A decrease in total acidity (TA) and juice yield during storage was observed for both cultivars; total soluble solids (TSS) increased only in the Tarocco oranges stored at 8 degrees C. The increase in TSS observed for Tarocco and the simultaneous decrease in TA in both varieties resulted in a higher maturity index (TSS/TA) for the two cultivars. No loss of vitamin C was noted in Tarocco orange at either temperature, whereas a sharp reduction in vitamin C occurred in the first 50 days of storage for Moro. A significant increase in anthocyanin content was observed in Tarocco and Moro stored at 8 degrees C. Overlong storage induces extensive hydrolysis of hydroxycinnamic derivatives to free acids in Moro orange and these, in turn, could develop the malodorous vinylphenols.     

热胁迫下丹参迷迭香酸代谢途径关键酶基因的表达研究

为探索热胁迫对丹参迷迭香酸途径关键酶基因表达的影响,采用定量RT-PCR法,以Actin与GAPDH作为内参基因,0~48h叶片cDNA作为模板,对迷迭香酸途径7个关键酶基因PAL、C4H、4CL、TAT、HPPD、HPPR和RAS的表达进行分析。通过试验结果构建出这7个关键酶基因0~48h代谢途径表达图谱。其中,PAL、C4H和RAS受热胁迫影响表达量下降;TAT、4CL和HPPD表达量呈先上升后下降趋势;HPPR表达量前期变化不大,后期呈下降趋势。结果表明热胁迫对迷迭香酸途径关键酶基因表达有极显著影响。该表达时序谱的建立为进一步研究热胁迫与酚酸类成分累积之间的关系奠定了基础。     

Active oxygen detoxifying enzymes and phenylalanine ammonia-lyase in the ethylene-induced chilling tolerance in citrus fruit

The effects of applying ethylene (2 microL x L(-)(1)) during cold storage of Fortune mandarins on the development of chilling-induced peel damage and on changes in the activities of the enzymes of the antioxidant system, superoxide dismutase, catalase (CAT), ascorbate peroxidase, guaiacol peroxidase, and glutathione reductase, and on phenylalanine ammonia-lyase (PAL) have been investigated. Chilling damage was reduced by applying ethylene during fruit storage at 1.5 degrees C. PAL activity increased in response to cold stress and was higher in fruit held under ethylene than under air during the whole storage period, whereas CAT was temporarily higher in ethylene-treated fruit. In contrast, the activities of the other enzymes were not increased by ethylene. The global results suggest that the ethylene-induced chilling tolerance in Fortune mandarins might be due to increased PAL and CAT activities.     

Orthophenylphenol and phenylhydroquinone residues in citrus fruit and processed citrus products after postharvest fungicidal treatments with sodium orthophenylphenate in California and Florida

Sodium orthophenylphenate (SOPP) has been used extensively for >40 years to control postharvest diseases of citrus fruits. Studies of the metabolism of [(14)C]SOPP have identified orthophenylphenol (OPP) as the major metabolite with phenylhydroquinone (PHQ) as a minor metabolite. The whole-fruit tolerance in the United States for OPP is 10 ppm. This study was conducted to quantify terminal OPP and PHQ residues in whole Navel oranges, grapefruit, and lemons following SOPP applications at maximum application rates and following commercial application and fruit storage practices. OPP and PHQ residues also were determined in products processed from treated Navel oranges. OPP residues in lemons, Navel oranges, and grapefruit treated with SOPP using foamer wash and shipping wax applications remained below the 10 ppm tolerance, and PHQ residues were all < or =0.439 ppm. PHQ residues in whole fruit increased with time in commercial storage. OPP residues in all Navel orange matrices except oil remained relatively stable with time in commercial storage; residues in oil declined substantially while in storage.     

刺葡萄愈伤组织UFGT基因克隆及表达分析

为从细胞水平上揭示刺葡萄3-O-类黄酮葡萄糖基转移酶(UFGT)基因调控花青素合成的功能,以刺葡萄愈伤组织为试验材料,根据刺葡萄愈伤组织转录组UFGT序列片段,利用RT-PCR结合RACE技术克隆得到VdUFGT基因,并对其进行生物信息学和表达特性分析。结果表明,VdUFGT基因cDNA和DNA开放阅读框(ORF)分别为1 371 bp和1 448 bp,包含2个外显子和1个内含子,编码456个氨基酸,为带负电荷的不稳定的亲水性蛋白,具有一个UDPGT结构域,是UDPGT超家族成员,包含UDP-黄酮糖基转移酶特征区域。由UFGT同源基因编码蛋白所构建的系统发育树,与植物进化的关系相一致,6个葡萄属植物聚为一支。RT-qPCR分析表明,刺葡萄红色愈伤组织VdUFGT转录水平极显著高于白色愈伤组织,培养25 d的2个细胞培养物差异可达79倍;在刺葡萄愈伤组织连续培养过程中,红色愈伤组织中VdUFGT转录水平变化幅度较大,在愈伤组织快速生长中期和衰老初期分别出现峰值,而刺葡萄白色愈伤组织VdUFGT转录水平与红色愈伤组织相比变化幅度不大,且始终维持在一个较低的水平。说明VdUFGT对刺葡萄红色愈伤组织细胞培养物中的花青素生物合成有重要的调控作用,这种调控作用主要发生在刺葡萄愈伤组织细胞快速生长中期和细胞衰老初期。本研究结果为进一步阐明VdUFGT调控刺葡萄细胞花青素合成的机制奠定了理论基础。     

Phenylalanine ammonia-lyase as related to ethylene in the development of chilling symptoms during cold storage of citrus fruits.

Low-temperature, nonfreezing, storage induces pitting and necrosis in the flavedo tissue of chilling susceptible citrus fruits. In this study the role of ethylene and phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) in the cold-induced citrus peel damage has been investigated. It has been shown that increasing PAL activity by applying ethylene at a nonchilling temperature did not cause fruit damage or reduce the incidence of this peel disorder when fruits were subsequently held at a chilling temperature (2 degrees C). The cold-induced peel damage was enhanced by applying inhibitors of PAL activity and ethylene synthesis and action. These results indicate that the induction of PAL and ethylene during fruit cold storage, but not before, plays a role in reducing the development of chilling symptoms. The cold-induced PAL activity was reduced by inhibitors of ethylene production, but inhibitors of ethylene action exerted little effect on the activation of this enzyme. Therefore, the activation of PAL may be dependent on ethylene but also an independent cold signal apparently related to the cold-induced peel damage.     

高湿贮藏对茄子冷害及抗氧化系统的影响

为探讨高湿贮藏对减轻茄子冷害的作用及其与抗氧化系统的关系,本试验将茄子果实分别放置于4℃的干雾控湿高湿冷库(相对湿度96%~99%)和低湿冷库(相对湿度70%~75%)中贮藏15 d,每隔3 d进行取样测定,比较分析相关指标的变化。结果表明,与低湿贮藏相比,高湿贮藏能显著抑制茄子果实冷害指数、相对电导率和失重率的上升(P<0.05),保持茄子果实较高的硬度及总酚和花青素含量。同时,高湿贮藏能显著提高茄子果实中超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)和过氧化物酶(POD)等抗氧化酶的活性(P<0.05),抑制过氧化氢(H₂O₂)和超氧阴离子( {\mathrm{O}}_2^{\frac{-}{·}} )的产生,保持更高的1,1-二苯基-2-三硝基苯肼(DPPH)和羟基自由基清除能力。上述结果表明,高湿贮藏可维持茄子果实较高的抗氧化系统活性,从而抑制活性氧对茄子的伤害,减轻果实冷害。本研究为高湿贮藏在茄子果实采后保鲜中的应用提供了一定的依据。     

减压贮藏对冷藏枇杷果实品质和木质化败坏的影响

为阐明低温减压贮藏对枇杷果实品质和木质化败坏的影响,该研究应用40～50 kPa压力于(0±0.5)℃下贮藏果实49 d,并每隔7 d测定果实的营养品质、出汁率、硬度、褐变指数、呼吸速率、乙烯产生速率、过氧化物酶(POD)和苯丙氨酸解氨酶(PAL)等木质化相关酶活性及木质素含量的变化.结果表明,减压处理可明显抑制冷藏枇杷果实的呼吸强度、乙烯产生和果实褐变,并保持较高的果实可溶性固形物、可滴定酸度和维生素C含量,抑制贮藏21 d后果实硬度的增加,减轻出汁率的下降,降低POD和PAL酶活性的上升趋势,抑制木质素含量的增加.另外,减压贮藏减轻冷藏枇杷果实的木质化败坏,可能与抑制POD和PAL酶活性有关.低温减压贮藏可有效保持果实食用品质,延长贮藏期,是适合枇杷果实贮藏的有效方法.     

Characterization of major anthocyanins and the color of red-fleshed Budd Blood orange (Citrus sinensis)

High-performance liquid chromatography (HPLC) with photodiode array detection was applied for the characterization of anthocyanins in red-fleshed Budd Blood (Citrus sinensis) orange. More than seven anthocyanin pigments were separated within 30 min by using a binary gradient (0.1% H(3)P0(4) in water and 0.1% H(3)PO(4) in acetonitrile) elution on a Prodigy ODS column. Separations by reversed-phase HPLC and semipreparative HPLC on a Prodigy 10-microm ODS Prep column, and acid and alkali hydrolyses were used for identification of anthocyanins. The primary anthocyanins in Budd Blood orange grown in Florida were cyanidin-3-(6"-malonylglucoside) (44.8%) followed by cyanidin-3-glucoside (33.6%). Two other minor pigments were also acylated with malonic acid. Malonated anthocyanins represented the major proportion (>51%) of anthocyanins in Budd Blood orange. Total anthocyanin contents and juice color parameters (CIE L,a,b) were compared with six other Florida-grown blood oranges.     

Differential expression of anthocyanin biosynthetic genes and anthocyanin accumulation in tartary buckwheat cultivars 'Hokkai t8' and 'Hokkai t10'

Six genes involved in anthocyanin biosynthesis in tartary buckwheat have been cloned, namely, FtC4H, Ft4CL, FtCHI, FtF3H, FtF3'H, and FtANS, which encode cinnamate 4-hydroxylase (C4H), 4-coumarate:CoA ligase (4CL), chalcone isomerase (CHI), flavones 3-hydroxylase (F3H), flavonoid 3'-hydroxylase (F3'H), and anthocyanidin synthase (ANS), respectively. Then, these cDNAs were used, along with previously isolated clones for phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS), to compare gene expression in different organs, flowering stages, and maturing seeds of tartary buckwheat cultivars 'Hokkai T8' and 'Hokkai T10'. Quantitative real-time polymerase chain reaction analysis showed that these anthocyanin biosynthetic genes were most highly expressed in the stems and roots of Hokkai T10. The FtANS gene was more highly expressed than other genes during flowering and maturing seeds. In addition, the anthocyanin concentration was higher in 'Hokkai T10' than in 'Hokkai T8'; however, naringenin chalcone, a flavonoid, was absent from 'Hokkai T10' seedlings based on fluorescence microscopy.     

Cinnamaldehyde inhibits enzymatic browning of cut lettuce by repressing the induction of phenylalanine ammonia-lyase without promotion of microbial growth

Cinnamaldehyde treatment inhibited the browning of cut lettuce during cold storage. In this study, to clarify the mechanism of inhibitory action of cinnamaldehyde against the browning and to show its microbiological merit, its effect on the browning of cut lettuce was compared to that of mild heat treatment. Both cinnamaldehyde and mild heat treatments inhibited the induction of phenylalanine ammonia-lyase (PAL) activity because of cutting. As a result, the biosynthesis of polyphenols, which are substrates of polyphenol oxidase, was inhibited. This reduction of polyphenol synthesis caused the inhibition of the browning. Cinnamaldehyde treatment repressed the induction of PAL mRNA, while mild heat treatment did not repress its induction. The increase in microbes in cut lettuce treated with cinnamaldehyde was less than that treated with mild heat after 12 days.     

云南红皮梨bHLH转录因子的生物信息学分析

具有碱性-螺旋-转角-螺旋结构的一大类基因被称为bHLH家族基因,其成员主要有c-MYC、MADL、MAX、MIXL和删r基因;bHLH转录因子在细胞的增殖、分化和凋亡方面起着重要作用;对植物的生长发育、营养吸收、生物合成和信号转导等方面同样有着重要作用。在果肉、叶片和外果皮中,CsMYC2的表达与CHS、UFGT及ANS表达相关联,因此CsMYC2参与花色苷的生物合成调控,但是该基因在云南红皮梨花色苷合成调控中起着什么样的作用尚不清楚。利用生物信息学方法对云南红皮梨（RedPyruspyrifdia）bHLH基因进行分析,对不同植物间bHLH基因氨基酸序列的同源性比对,并且对该基因编码的蛋白质的理化性质、结构和功能等进行预测和分析。结果表明：该蛋白属于亲水性蛋白,其二级结构中的主要结构元件是仅一螺旋和无规则卷曲,并散布于整个蛋白。这一结果为研究红皮梨bHLH基因的结构、功能以及红皮梨的着色机制奠定了一定的基础。     

Volatile emissions of navel oranges as predictors of freeze damage

Volatile emissions of navel orange (Citrus sinensis L. Osbeck cv. Washington) fruit were evaluated as a means for predicting and gauging freeze damage. The fruits were subjected to -5 or -7 degrees C treatments in a laboratory freezer for various time periods of 2-9.5 h and stored at 23 degrees C for 1, 2, or 7 days, after which time the emission of volatiles from the fruit was measured. Following the final day of volatile measurements the fruits were stored at 5 degrees C for an additional 2-3 weeks and then evaluated for fruit quality characteristics. Peel injury in the form of brown lesions, drying of the juice vesicles, a decline in acidity, and a loss of flavor were observed to occur as a result of freezing. Corresponding to the loss in fruit quality were large increases in the emissions of ethanol, ethyl butanoate, methyl hexanoate, and ethyl octanoate. With the exception of methyl hexanoate, for which volatile emissions decreased during storage for 7 days at 23 degrees C, all of the other volatiles were relatively unchanged in amount by storage. Treatment at -7 degrees C caused greater injury, quality loss, and more volatile emanation than did freezing at -5 degrees C. The measurement of volatile emissions appears to be a useful approach to identify freeze-damaged navel oranges.