Ineractions between a mild and a severe strain of potato spindle tuber viroid in doubly infected potato plants

Potato (Solarium tuberosum) plants co-infected with a mild and a severe strain of potato spindle tuber viroid (PSTVd) were analyzed by return-polyacrylamide gel electrophoresis for the presence of both strains in vegetative and reproductive plant parts. Both strains were detected in the anthers, flowers, inflorescences, leaves, ovaries, ovules, petals, pistils, roots, sepals, stolons and tubers. Only mild strain was detected from pollen in the cultivars tested. True potato seed (TPS) were not doubly infected when they were obtained from co-infected maternal parent plants pollinated with pollen from healthy plants. Also, when maternal plants infected with severe strain were pollinated with pollen from healthy plants or from those infected with the mild strain, TPS were not doubly infected. A small number of TPS with double infection was obtained when co-infected or mild-strain-infected plants were pollinated with pollen containing the severe strain (singly or doubly infected). The number of TPS containing mild strain predominated in a ratio of 7:1 over TPS containing the severe strain. This study indicates that segregation of strains from doubly-infected plants probably takes place during pollen formation and persists through seed development.     

A simple and rapid method for the detection of potato spindle tuber viroid (PSTVd) by RT-PCR

Summary A test procedure for PSTVd is described based on immobilisation of plant sap on filter paper, by dotting or tissue printing followed by RT-PCR. Tests were carried out using primarily and secondarily infected potato plants, primarily infected in vitro plants, and potato tubers. Print PCR was shown to be suitable for testing large samples of potato plants whereas dot PCR is recommended for in vitro plantlets and tuber tissue. Bulking one infected plant to 4 or 9 healthy plants gave reliable results with secondarily infected potato plants, but sometimes the test failed to detect PSTVd in primarily infected in vitro plants. Dotted and printed paper squares could be stored at 4°C for at least 2 weeks in Triton X-100 solution or under dry conditions. Storing at room temperature can lead to unreliable results.     

马铃薯纺锤块茎类病毒不同株系及不同接种方法对产量的影响

马铃薯纺锤块径类病毒(Potato spindle tuber viroid)是危害黑龙江省马铃薯生产的一种重要病害。为了查明不同类病毒变株对主栽品种克新1号和4号所引起的产量损失和症状反应,应用往复聚丙烯胺凝胶电泳法(Peturn-Polyacmdegel electophoresis)鉴定类病毒。试验结果表明,接种当年,接种类病毒的处理平均减产37%,按商品产量计算减产达47%。当年表现症状的植株平均为59.6%,块茎产生症状的植株平均为57.4%。用于接种的3个马铃薯纺锤块茎类病毒变株的致病力,以当地的类病毒弱系为最强,其次为北美的类病毒强系,北美的类病毒弱系的致病力较弱。类病毒对产量的影响与马铃薯品种和类病毒变株的组合有极为密切的关系。克新1号接种当地的类病毒弱系时薯块严重畸变,商品产量只为不接种对照的21%。用往复电泳法检测各个试验处理被类病毒侵柴的情况,芽接种处理,于出苗后1周即可检测到类病毒,叶接种处理,于接种后2周即能检测到类病毒。出苗后7周,植株中类病毒浓度达到高峰,随即急剧下降,到出苗后10周,大部分接种植株已检测不到类病毒。块茎直径达1厘米时,即能检测到类病毒,随着块茎膨大,类病毒浓度也相应增高,到收获前,块茎中的类病毒含量只略低于植株含类病毒高峰期的浓度。用于本试验的克新1号、4号无类病毒和主要马铃薯病毒的核心材料,在1988年已交付给省内外的良种场繁殖使用。于当年秋季抽样检测克山第二良种场连续种植二年的种薯,当年种植试管苗生产的种薯,以及试管苗等,均未检测到类病毒。     

Survey of potato spindle tuber viroid in seed potato growing areas of the United States

Fourteen United States (U.S.) seed potato certification agencies surveyed all U.S. seed potato growing areas for presence of the potato spindle tuber viroid (PSTVd). The survey included general surveillance, which involved searching for the occurrence of PSTVd in state seed potato certification records from 1990 through 2000, and a field survey, which involved testing selected crops for PSTVd infection by nucleic acid dot blot hybridization during 1999 through 2001. No PSTVd incident was documented in any of the state certification records, nor was PSTVd detected in the field surveys. All U.S. seed-growing areas were determined to be free of PSTVd. It is concluded that PSTVd has been eradicated and freedom from potato spindle tuber viroid has been successfully maintained in all of the seed potato growing areas in the United States.     

马铃薯晚疫病种薯带菌的分子检测

从马铃薯块茎上分离纯化得到晚疫病菌、银腐病菌、癌肿病菌、红腐病菌、黑点病菌和镰刀菌等并提取它们的全基因组DNA,用引物08-3和08-4对这些真菌的DNA进行PCR扩增,以检验该引物扩增晚疫病菌DNA的特异性。取马铃薯种薯的芽眼、芽及其他不同部位并用NaOH法提取晚疫病菌DNA,再用引物08-3和08-4进行特异性扩增以检验种薯是否带晚疫病菌。结果表明:(1)引物08-3和08-4有很强的特异性,只能扩增出大小为257bp的马铃薯晚疫病菌DNA片段;(2)用该引物能扩增出种薯芽眼组织中大小为257bp的晚疫病菌DNA,说明通过PCR特异扩增,能直接检测出马铃薯种薯中潜伏的晚疫病菌。(3)本次检测的本地感病品种米拉有10%的种薯带晚疫病菌。该研究为种薯传播晚疫病菌的分子检测提供了依据和方法。     

Assessing the resistance to gangrene of progenies of potato (Solanum tuberosum L.) from parents differing in susceptibility

Summary The resistance to gangrene (caused byPhoma exigua var.foveata) of progenies from two hybridisation schedules involving cultivars resistant, susceptible, or of intermediate reaction to gangrene was assessed. Two methods of sampling tubers from field-grown single-plant plots of 18 clones representing each progeny were used: one tuber was taken from each plant, and a bulk sample of 18 tubers was selected at random from the whole progeny. Gangrene resistance was assessed after incubating tubers which had been rolled in cornmeal-sand inoculum ofP. exigua var.foveata, and was expressed as a percentage of tubers infected. Results from the two methods of sampling correlated closely, and agreed well with tests in a subsequent year on 10-tuber samples of each individual clone. It is concluded that an 18-clone sample adequately represented each progeny, and that the mid-parent gangrene score satisfactorily predicted the resistance of the resulting progeny. There are indications that susceptibility tended to be dominant. The implication of these findings to breeding for resistance to gangrene is discussed.     

Disease eradication and propagation of the initial seed potato material in Estonia

Summary The EVIKA Research Centre has developed a disease eradication system for the initial material of seed potato, which consists of 1. Selection of the initial material for eradication, plant thermotherapy, meristem tip cultivation and testing for viruses; 2. Re-eradication (thermotherapy of test-tube plants, cultivation of meristem tips, testing for viruses, testing of varietal quality and yield of disease-free meristem clones, and the selection of meristem clones with best varietal characteristics; 3. Renewing of the initial material (all processes as above, but the initial material is selected from the seed potatoes grown for at least 3 years in the field). Field trials were conducted after the second cycle of eradiaction to determine whether the plantlets were true-to-type and to assess the yield, disease resistance and tuber dry matter. Recently we have also started in vitro testing of meristem plants resistance to late blight, hoping that this approach will improve the selection efficiency. Propagation and growing of the seed tubers consists of 3 main steps: 1. Plantlet propagation in vitro; 2. Greenhouse propagation in plastic rolls; and 3. Planting the first generation tubers in the field. Under our conditions it is the cheapest, simplest and most effective way. Multiplication of the meristem-derived plants is done by shoot tip cuttings in a greenhouse in plastic rolls with peat as the growing medium. The first generation of seed tubers is grown in the field. In our trials plant productivity was affected by the method of multiplication, growing conditions and genotype. The highest yield per hectare was obtained with plants multiplied in plastic rolls. The in vitro plants had more tubers per plant than plants multiplied in plastic rolls. In seed production fields the productivity of plants was more influenced by following our instructions than by multiplication and growing methods. The number of tubers per plant obtained with over 0.5 million plants was 6.5–9.0. In the second generation of seed tubers, grown under equal density, the greater-sized tubers gave more tubers with lower weight than the smaller-sized tubers. Cutting tubers had no effect on the plant development and tuberization.     

Growth attributes of potato and their inter-relationship with yield

Summary In the mild and short winter of the Ganges plains, the yield contributing characters such as number of shoots/plant, plant height, leaflet size, tuber yield/plant and tuber number/plant were studied for fifty varieties of potato. From the simple, partial and genotypic and phenotypic correlation studies it was observed that leaflet size, number of tubers/plant and plant height were closely connected with the yield of potato tubers. A multiple regression equation was also prepared and it was found that the leaflet size had the maximum influence on yield followed by number of tubers/plant and plant height.     

无机焦磷酸化酶基因的克隆与植物表达载体的构建

提取面包酵母基因组DNA,用无机焦磷酸化酶(PPase)基因特异引物通过PCR扩增出864bp的片段,并将该片段克隆至pMD18-T上。序列分析结果表明,该克隆序列与GeneBank上的PPase基因序列同源性达到100%。进一步将叶肉细胞特异性启动子rbcS和PPase基因克隆至植物表达载体pCBI上,构建了由rbcS启动子调控的PPase基因植物表达载体pCBIPR。通过冻融法将重组质粒导入根癌农杆菌EHA105中,为农杆菌介导的PPase基因对植物的遗传转化奠定基础。     

胶孢炭疽病菌环境pH应答转录调控因子基因的克隆与分析

参照油梨炭疽病菌(Colletotrichum gloeosporioides)的环境pH应答转录因子基因Pacl设计l对特异性引物,以芒果炭疽病菌(C.gloeosporioides)基因组DNA为模板,扩增获得大小为2 625 bp的目的基因片段.序列分析结果表明,目的片断包含完整的阅读框,与油梨炭疽病菌C.gloeosporioides pac1基因相应片段长度相同,二者碱基序列同源性达97%.用RT-PCR技术获得pacl基因cDNA片段,证实目的基因片段中存在3个大小分别为59,50,71 bp的内含子.拼接的全长cDNA长1 755 bp,推测编码的氨基酸序列长584个氨基酸残基,与推测的油梨炭疽病菌pacl基因所编码的蛋白质同样大小,二者氨基酸序列相似性达99%,只有1个氨基酸的差异,可以肯定克隆的目的片段为C.gloeosporioides pac1基因,为进一步研究C.gloeosporioides侵染芒果时的pH调控奠定了基础.     

Incidence of potato tuber blight in Ecuador

Potato late blight, caused byPhytophthora infestans (Mont.) de Bary, is the most important biotic constraint to potato yield and productivity in Ecuador. Yields are severely reduced by foliage blight, but tuber blight has never been quantified in this country. To address this issue, three independent surveys were carried out in Ecuador to estimate the incidence of tuber infection byP. infestans. The first two (1998–1999) involved the collection and assessment of more than 8,000 tubers from the four provinces that produce the most potatoes: Carchi, Chimborazo, Pichincha, and Tungurahua. In the third survey (1999–2001), approximately 10,000 tubers were sampled from the two provinces producing the most potatoes, Carchi and Chimborazo, and from Canar and Bolivar, two provinces that produce relatively small amounts. In spite of confirmed foliage infection in most fields sampled, very few infected tubers were found. In 1999, an extremely low incidence of tuber blight (less than 0.1%) was detected in three samples (each of more than 1,000 tubers) from the province of Pichincha. In a separate survey in 1999, tuber blight was also found in three fields in the province of Carchi, but with very low incidence. Our data indicate that tuber blight does occur in Ecuador, but the incidence of the disease is extremely low. Factors that might suppress tuber blight in Ecuador are discussed.     

Potato blackleg disease

Blackleg, a bacterial soft-rot of potatoes caused byErwinia atroseptica, has been recognized since the turn of the century as a disease capable of causing tremendous losses to the crop in the field or in storage. The pathogen is both seed- and soil-borne, and generally attacks the seed piece through wounds caused by insect larvae, fertilizer burns, frost injury, bruises, or lesions caused by other pathogenic bacteria and fungi. Infection is increased by low temperature and high moisture, especially in the soil. These conditons are less than optimum for the pathogen, but are less favorable for the infected plant, as they slow normal growth and prevent formation of protective cork tissue which would restrict the spread of the infection. Partial control of this disease can be effected by using seed free from disease, sanitation, crop rotation, planting in well-drained soils, prevention of any wounds or diseases which would permit entry of the pathogen, planting resistant varieties, seed treatment, and proper storage conditions for freshly dug tubers and cut tubers if they cannot be planted immediately.     

爱玉子性别与品系的SRAP分析

爱玉子雌、雄异株,其性别以及品系在结果前难以通过枝叶等形态特征进行辨别.作者将序列相关扩增多态性(SRAP)标记应用于爱玉子性别及品系鉴别研究,建立了完整的PCR反应体系,扩增效果好,结果稳定可靠,可重复性强.在153对SRAP引物中,只有引物me_5-em_4在爱玉子雌株上扩增出约220 bp的特异条带,将其命名为FA me_5-em_(14)-220,该标记与雄株没有关联,可作为爱玉子性别鉴别的SRAP标记.从153对引物中筛选出8对多态性好、分辨率高的引物组合,在24个爱玉子雌性品系和16个雄性品系的DNA样品中扩增出171条多态性带,并获得爱玉子雌、雄各品系独特的核酸指纹,其中em_6-me_6引物与me_3-em_2、me_1-em_8、me_2-em_9中的任何一对引物进行组合,都能鉴别24个爱玉子雌性品系;me_3-em_2与me_9-em_(14)2对引物组合也能鉴别24个爱玉子雌性品系;me_1-em_8单独一对引物,以及me_1-em_9与me_3-em_2(或me_6-em_6)2对引物组合能鉴别16个爱玉子雄性品系,并获得2个雄性品系的特异性片段,即片段me_1-em_8-350 bp为大洋57特有,me_1-em_8-240bp为大洋241特有.研究结果对爱玉子种质资源遗传多样性的分析、品种和品系的鉴定、以及种苗质量仲裁检验等具有重要的理论意义和实践价值.     

Extraction ofclaviba cter michiganensis subsp.sepedonicus from composite samples of potato tubers

The presence ofClavibacter michiganensis subsp.sepedonicus was detected by immunofluorescence and ELISA in diluent in which cores from 200 potato tubers had been incubated on a rotary shaker. By this procedure the ring rot pathogen was detected in composite samples from naturally infected tubers and tuber samples “spiked” with infected tissue or a pure culture of the pathogen. Populations of saprophytic bacteria increased about 100-fold in the diluent during 18 h of incubation but did not interfere with serological detection of C.m. sepedonicus. Some of the results suggest thatC. m. sepedonicus cells multiply during incubation of tuber samples. Extraction of ring rot bacteria from potato tuber tissue by incubation on a rotary shaker requires little work and minimizes the amount of plant tissue in the extract compared to the standard extraction procedure involving maceration and differential centrifugation.     

利用多重PCR技术快速鉴定番木瓜性别

利用鉴定番木瓜雄性性别的特异基因片段(1 001 bp)的引物和鉴定番木瓜雄性、两性性别的特异基因片段(225 bp)的引物,分别以5个品种番木瓜的3种性别植株的总DNA为模板进行多重PCR扩增,结果表明:以雄株总DNA为模板得到1个1 001 bp和1个225 bp的扩增产物,以雌株总DNA为模板没有得到扩增产物,以两性株总DNA为模板得到1个225bp的扩增产物,根据多重PCR扩增结果,可以将番木瓜3种性别植株一次性鉴定出来.     

氮素形态与马铃薯品质的关系

在田间条件下研究了不同形态氮素对马铃薯块茎硝酸盐含量、淀粉、蛋白质及还原糖含量的影响。结果表明,马铃薯块茎内硝酸盐含量从块茎形成期到成熟收获期是逐渐降低的。使用铵态氮肥并加硝化抑制剂双氰胺可以显著地抑制马铃薯块茎硝酸盐的积累;与硝酸盐含量变化相似,从块茎形成期到收获期蛋白质含量也逐渐降低,不同氮素形态处理对马铃薯块茎内蛋白质含量的影响无显著差异;铵态氮添加双氰胺处理可降低块茎还原糖含量。虽然马铃薯被认为是喜硝作物,但本研究表明,不同氮素形态处理不仅没有造成马铃薯产量的显著差异,而且块茎内淀粉含量也无显著差异。     

大豆种皮特异性启动子的克隆及功能分析

采用PCR技术从大豆品种吉农17基因组DNA中分离得到大豆种皮特异性启动子片段SCSP,长度约为1268 bp.序列分析表明SCSP与报道序列同源性达97%以上.将其与GUS基因融合,构建植物表达载体pSCSP-GUS后,转化到EHA105根癌农杆菌中,通过根癌农杆菌(Agrobacterium tumefaciens)介导法转化烟草(Nicotiana tabacum)NC89.转基因植株的GUS活性检测表明,仅能在种皮检测到GUS活性,而在茎、叶和花等其它组织中都未检测到GUS活性,证实SCSP片段具有种皮特异性表达功能.     

Relationship of potato tuber periderm resistance to plant water status

Potato (Solanum tuberosum L. cv. Russet Burbank) tuber periderm resistance to water loss was monitored during the harvest season. Periderm resistance of tubers from water-stressed plants was compared with tubers from unstressed plants throughout a six-week harvest period, in order to determine the effect of plant condition on tuber resistance to water loss. Tubers stored for ten days at 4°C immediately following harvest were also monitored to determine if storage enhanced periderm resistance and if any difference occurred between tubers from stressed vines compared with those from unstressed vines. During the harvest season, tuber resistance to water loss was positively correlated with plant water stress, as measured by leaf water potential and leaf diffusive resistance. Storage of tubers after harvest also caused an increase in periderm resistance. The commercial practice of vine killing, therefore, may have a positive effect on reducing weight loss in storage by enhancing the resistance of tuber periderm to water loss.     

湖南省马铃薯主产区马铃薯病毒种类及流行分析

马铃薯是世界第四大粮食作物,其病毒病危害严重。2010年对湖南马铃薯主产区采集的66个病毒标样进行了RT-PCR检测,结果表明,检测出的马铃薯病毒有马铃薯Y病毒(PVY)、马铃薯卷叶病毒(PLRV)、马铃薯X病毒(PVX)、马铃薯S病毒(PVS)、马铃薯A病毒(PVA)和马铃薯纺锤块茎类病毒(PSTVd)。其中PVS的检出率最高,为54.5%,其次是PVX,检出率为45.5%,PVY的检出率为39.4%,PSTVd和PVA的检出率均为21.2%,PLRV的检出率为18.2%。2~4种病毒的复合侵染现象较为普遍。PVY中重组型PVY占85.7%。     

油菜野芥细胞质雄性不育恢复基因候选片段的克隆

根据植物细胞质雄性不育恢复基因编码的PPR（pentatricopeptide repeat）蛋白的特点,结合拟南芥PPR基因簇相似序列,扩增油菜野芥细胞质雄性不育(Nsa CMS) 基因组DNA,筛选出一对简并引物,在Nsa不育系育性恢复后的可育材料和野芥亲本中可以同时扩增出符合预期的片段。片段长度为309bp,与萝卜CMS恢复基因核苷酸序列的一致性为69%,与拟南芥1号染色体臂上PPR基因簇核苷酸序列的一致性大于70%,与含波里马（Pol）CMS恢复基因的白菜型油菜相关序列一致性达85%。该片段编码的氨基酸序列含有两个相邻排列的PPR基序,可作为Nsa CMS育性恢复基因的候选片段。