B型烟粉虱在四种葫芦科寄主植物上的发育和繁殖

研究了B型烟粉虱在4种葫芦科寄主植物黄瓜、节瓜、苦瓜和丝瓜上的发育和繁殖特性.结果表明,B型烟粉虱在节瓜上的世代发育历期最短,为19.3 d,在苦瓜上的世代发育历期最长,为29.0 d;世代存活率在黄瓜上最高,为92.85％,在苦瓜上最低,为53.08％;平均单雌产卵量在黄瓜上最多,为187.4粒,苦瓜上最少,为30.0粒;雌成虫寿命以在黄瓜上最长,为25.2 d,在苦瓜上最短,为10.9 d.B型烟粉虱在黄瓜、节瓜、苦瓜和丝瓜上的内禀增长率（r_m）分别为0.1453、0.1429、0.0616和0.1055.综合比较4种葫芦科植物,黄瓜是B型烟粉虱的最适宜寄主.     

黄瓜花叶病毒和烟草花叶病毒在双抗转基因线辣椒内的增殖

本试验以转化CMV CP和TMV CP基因的转基因线辣椒纯合系植株作为研究试材 ,比较了单独或混合接种CMV和TMV后 ,转化线辣椒的抗病性表达特点 ,并测定了两种病毒在植株体内的病毒含量。结果表明 :转化线辣椒不仅能抵抗CMV和TMV的单独侵染 ,而且还能抵抗CMV和TMV的复合侵染。转化线辣椒表现为系统症状延迟出现 7 15d ,显症株率和病害严重度级别大幅度降低 ,CMV和TMV在接种叶、新生叶中的病毒含量明显减低。转基因线辣椒原生质体作为研究试材接种CMV ,测定病毒含量结果表明 :CMV病毒的增殖在转基因线辣椒原生质体内受到明显抑制。在CMV接种浓度为 4 0 μg/mL ,感染原生质体 4 8h后 ,CP(- )植株原生质体内CMV是CP( )的 4 .2倍。这一结果揭示了转基因线辣椒具有抑制病毒增殖的抗病性。     

Role of lipopeptides produced by Bacillus subtilis GA1 in the reduction of grey mould disease caused by Botrytis cinerea on apple

AIM: Test of Bacillus subtilis strain GA1 for its potential to control grey mould disease of apple caused by Botrytis cinerea. METHODS AND RESULTS: GA1 was first tested for its ability to antagonize in vitro the growth of a wide variety of plant pathogenic fungi responsible for diseases of economical importance. The potential of strain GA1 to reduce post-harvest infection caused by B. cinerea was tested on apples by treating artificially wounded fruits with endospore suspensions. Strain GA1 was very effective at reducing disease incidence during the first 5 days following pathogen inoculation and a 80% protection level was maintained over the next 10 days. Treatment of fruits with an extract of GA1 culture supernatant also exerted a strong preventive effect on the development of grey mould. Further analysis of this extract revealed that strain GA1 produces a wide variety of antifungal lipopeptide isomers from the iturin, fengycin and surfactin families. A strong evidence for the involvement of such compounds in disease reduction arose from the recovery of fengycins from protected fruit sites colonized by bacterial cells. CONCLUSIONS: The results presented here demonstrate that, despite unfavourable pH, B. subtilis endospores inoculated on apple pulp can readily germinate allowing significant cell populations to establish and efficient in vivo synthesis of lipopeptides which could be related to grey mould reduction. SIGNIFICANCE AND IMPACT OF THE STUDY: This work enables for the first time to correlate the strong protective effect of a particular B. subtilis strain against grey mould with in situ production of fengycins in infected sites of apple fruits.     

Biolistic mediated site-specific integration in rice

Cre-lox mediated site-specific integration in tobacco or Arabidopsis used polyethylene glycol or Agrobacterium, respectively, to deliver the integrating DNA. The polyethylene glycol method is inconvenient since it requires the use of protoplasts. The Agrobacterium method is inefficient as the single-stranded T-DNA is not a substrate for Cre-lox recombination. In this study, we tested the biolistic method for the site-specific insertion of DNA into the rice genome. Two target callus lines, each harboring a single genomic lox target, were generated by Agrobacterium-mediated transformation. The target callus lines were subjected to a second round of transformation by particle bombardment with a construct designed to excise the plasmid backbone from the integrating DNA, followed by the recombination of the integrating DNA into the genomic lox target. Site-specific integration was obtained from both target callus lines. Three integrant plants were regenerated from one target line and were found to have a precise copy of the integrating DNA at the target site, although only one plant has the integrating DNA as the sole copy in the genome. Site-specific integration through the biolistic delivery of DNA can be considered for other plants that are transformable via particle bombardment.     

Monitoring changes in anthocyanin and steroid alkaloid glycoside content in lines of transgenic potato plants using liquid chromatography/mass spectrometry

Transgenic potato plants overexpressing and repressing enzymes of flavonoids biosynthesis were created and analyzed. The selected plants clearly showed the expected changes in anthocyanins synthesis level. Overexpression of a DNA encoding dihydroflavonol 4-reductase (DFR) in sense orientation resulted in an increase in tuber anthocyanins, a 4-fold increase in petunidin and pelargonidin derivatives. A significant decrease in anthocyanin level was observed when the plant was transformed with a corresponding antisense construct. The transformation of potato plants was also accompanied by significant changes in steroid alkaloid glycosides (SAG) level in transgenic potato tuber. The changes in SAGs content was not dependent on flavonoid composition in transgenic potato. However, in an extreme situation where the highest (DFR11) or the lowest (DFRa3) anthocyanin level was detected the positive correlation with steroid alkaloid content was clearly visible. It is suggested that the changes in SAGs content resulted from chromatin stressed upon transformation. A liquid chromatography/mass spectrometry (LC/MS) system with electrospray ionization was applied for profiling qualitative and quantitative changes of steroid alkaloid glycosides in tubers of twelve lines of transgenic potato plants. Except alpha-chaconine and alpha-solanine, in the extracts from dried tuber skin alpha-solamargine and alpha-solasonine, triglycosides of solasonine, were identified in minor amounts, triglycosides of solanidine dehydrodimers were also recognized.     

The promoter of the pepper pathogen-induced membrane protein gene <Emphasis Type="Italic">CaPIMP1</Emphasis> mediates environmental stress responses in plants

The promoter of the pepper pathogen-induced membrane protein gene CaPIMP1 was analyzed by an Agrobacterium-mediated transient expression assay in tobacco leaves. Several stress-related cis-acting elements (GT-1, W-box and ABRE) are located within the CaPIMP1 promoter. In tobacco leaf tissues transiently transformed with a CaPIMP1 promoter-β-glucuronidase (GUS) gene fusion, serially 5′-deleted CaPIMP1 promoters were differentially activated by Pseudomonas syringae pv. tabaci, ethylene, methyl jasmonate, abscisic acid, and nitric oxide. The −1,193 bp region of the CaPIMP1 gene promoter sequence exhibited full promoter activity. The −417- and −593 bp promoter regions were sufficient for GUS gene activation by ethylene and methyl jasmonate treatments, respectively. However, CaPIMP1 promoter sequences longer than −793 bp were required for promoter activation by abscisic acid and sodium nitroprusside treatments. CaPIMP1 expression was activated in pepper leaves by treatment with ethylene, methyl jasmonate, abscisic acid, β-amino-n-butyric acid, NaCl, mechanical wounding, and low temperature, but not with salicylic acid. Overexpression of CaPIMP1 in Arabidopsis conferred hypersensitivity to mannitol, NaCl, and ABA during seed germination but not during seedling development. In contrast, transgenic plants overexpressing CaPIMP1 exhibited enhanced tolerance to oxidative stress induced by methyl viologen during germination and early seedling stages. These results suggest that CaPIMP1 expression may alter responsiveness to environmental stress, as well as to pathogen infection. The nucleotide sequence data reported here has been deposited in the GenBank database under the accession number DQ356279.     

转基因小麦“中间试验”与农艺性状评价

在湖北武汉对3个转基因小麦品系连续2次进行了"中间试验".结果表明在田间栽培条件下,转基因小麦植株个体生长发育正常,但转基因小麦主要农艺性状与对照间存在差异;特别是小区产量与本地小麦品种之间存在极显著差异;转基因小麦品系与其受体品系之间千粒重和小区产量上存在显著差异或极显著差异.组织化学和SDS-PAGE检测结果表明,外源基因能够稳定遗传,功能得到正确表达.     

贮藏温度和气体状况对苹果果胶、多聚半乳糖醛酸酶变化的影响

在苹果贮藏前期温度和CO_2浓度由高到低同步变动形成双维变动气调(TDCA)。 前期高温期间,果实予以高浓度CO_2处理,可抑制高温促使早熟的不利效应,其保鲜效果优于冷库,接近传统气调贮藏,表现在果肉硬度下降平缓;原果胶转化为水溶性果胶的速度减慢;多聚半乳糖醛酸酶活性显著受抑。低浓度CO_2抑制高温效应的作用大为减弱。低温下,不同浓度CO_2作用差异不大,均优于对照。     

Susceptibility of dopamine D5 receptor targeted mice to cysteamine

BACKGROUND: Recently we demonstrated that gastric mucosa of rats can synthesize, store and release dopamine. Out of five different subtypes, mRNA of D5 (=D1b) dopamine receptor is very abundant in the gastric epithelium. D1 receptor selective dopamine agonists have been shown to protect against experimental gastro-duodenal lesions. AIMS: To test the hypothesis that protective effects of dopamine involve D5 receptors, mucosal lesions were induced in D5 receptor deficient (KO) and wild-type (WT) mice using cysteamine. Morphology and gastric acid secretion of D5 KO mice were also studied. METHODS: Single doses of 600 mg/kg, 300 mg/kg cysteamine or vehicle were administered subcutaneously to fasted animals. After 24 h, number and severity of gastro-duodenal lesions were analyzed. Basal and histamine-induced maximal gastric acid output were measured by a stomach-sac wash-through method. RESULTS: All the KOs in the 600 mg/kg cysteamine group died within 4 h showing symptoms of toxicity while three out of four WTs survived (P<0.05). Mortality after 300 mg/kg cysteamine was significantly higher in KOs versus the WTs: 6/14 versus 2/11, P<0.05. Gastric lesion-index was also significantly higher in KOs (median, middle quartile): four (3-9) versus 0 (0-0), P<0.05. Duodenal lesions did not develop from this single dose of cysteamine in either genotype. Basal and histamine-induced maximal gastric acid output were comparable in the two genotypes. CONCLUSIONS: This study demonstrates that loss of D5 receptor causes mucosal vulnerability and increased toxicity of cysteamine in genetically manipulated mice. Thus, D5 receptor subtype is indeed likely to be involved in protective effects of dopamine in the stomach.