转rolA、B、C基因枳橙快繁技术

通过对转rol基因枳橙B、D、E系及对照的高接植株春梢茎段进行萌芽诱导、增殖及试管苗生根成苗的试验,摸索出适宜枳橙快繁各种培养基配方及培养条件。结果表明,以MS+6-BA1mg/L的培养基适合于芽萌发,以MS+6-BA0.5mg/L+NAA0.05mg/L的培养基适合于芽增殖,生根则以1/2MS+NAA0.5mg/L+0.2%活性炭的组合最佳,转基因各系生根率均在93.3%以上,显著高于对照生根率(66.7%)。快繁苗移栽成活率可达90%,目前生长良好。     

基于远缘杂交的黄瓜种质资源的创新与利用研究

未来作物改良的最大希望在于有用外源基因的导入，远缘杂交是导入外源有用基因的主要途径之一。基于笔者近年来在甜瓜属（Cucumis）种间杂交所取得的进展，本文综述了甜瓜属种间杂交双二倍体、异源三倍体、单体异附加系和异源易位系的合成、鉴定和定性研究，以及对外源有用基因，包括抗病、抗逆性的转导利用情况，并展望了这些特异种质资源在甜瓜属作物的遗传和品种改良上的理论和实践价值。     

Note: Pyrethroid resistance and possible involvement of glutathione<Emphasis Type="Italic">S</Emphasis>-transferases in<Emphasis Type="Italic">Helicoverpa armigera</Emphasis> from Turkey

An introductory study was conducted to investigate the pyrethroid resistance ofHelicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) strains in Turkey, collected from cotton fields in the Adana and Antalya provinces, through two different synthetic pyrethroid insecticides: lambda-cyhalothrin and esfenvalerate. In addition, the roles of glutathioneS-transferases (GSTs) in this resistance mechanism were analyzed. It was found that whereas resistance ratios for lambda-cyhalothrin (LD₅₀ levels) were 3- and 98-fold increased in the Adana and Antalya strains, respectively, esfenvalerate ratios were 3.3- and 92.3-fold increased in the Adana and Antalya strains, respectively, with respect to the susceptible strain. Furthermore, Adana and Antalya strains showed 2.4- and 2.9-fold higher GST activities than the susceptible strain, respectively. In the Antalya field strain, the minor increase in GST activity compared with the resistance levels implies that GSTs may be not greatly involved in this resistance. It also provides evidence that they could not be the only metabolic mechanism responsible for resistance to lambda-cyhalothrin and esfenvalerate inH. armigera from Turkey. http://www.phytoparasitica.org posting Nov. 16, 2006.     

两种季铵盐阳离子表面活性剂对番茄灰霉病菌的生物活性

为探讨季铵盐阳离子表面活性剂在番茄灰霉病防治中的应用潜力,室内采用菌丝生长速率法测定了五种阳离子表面活性剂对番茄灰霉病菌Botrytis cinerea的毒力作用,筛选出具有较高抑菌活性的1227(十二烷基二甲基苄基氯化铵)和C8-10(双八、十烷基季铵盐),并研究了其对该菌菌丝干重、分生孢子萌发、产孢量、菌核形成及细胞膜透性的影响。结果表明,五种阳离子表面活性剂中1227和C8-10对病原菌菌丝生长有较强的抑制作用,EC50值分别为8.39和5.82μg/mL,其毒力高于常规对照药剂腐霉利水悬浮剂,与嘧霉胺水悬浮剂、乙霉威水悬浮剂相当。两者对菌丝干重、孢子萌发均有较强的抑制作用,20μg/mL时抑制率接近或达到100%;对菌核数、菌核形态及分布有一定影响;40μg/mLC8-10对该菌产孢量的抑制率可达90%以上;1227和C8-10的浓度大于20μg/mL时均能明显影响病原菌细胞膜的通透性。     

Critical Use Exemption for methyl bromide for soil disinfestation: Italy’s experience with the European union process

Methyl bromide (MB) was phased out on January 1, 2005, and a Critical Use Exemption (CUE) process has been established in order to define the rules for allocating the needed amounts of the fumigant. This paper deals with the effects of the CUE process on Italian horticulture. The actual usage of the amounts of MB allocated to Italy for the year 2005 in the different areas and on the economically most important crops was monitored and critically evaluated. The usage pattern monitored shows that already in the first year after MB phaseout, Italy was able to replace it completely on crops such as zucchini, salad greens, basil and watermelon. However, on crops such as tomato, pepper, melon, eggplant, strawberry, and cut flowers, further work is required in order fully to replace MB. The emerging problems and research needs are discussed briefly.     

Towards identifying pathogenic determinants of the chickpea pathogen <Emphasis Type="Italic">Ascochyta rabiei</Emphasis>

Ascochyta blight is a serious disease of cool-season grain legumes (chickpea, faba bean, lentil and pea) caused by fungal species of the anamorphic genus Ascochyta and related genera. Despite extensive studies on the biology, ecology, epidemiology and management of the disease, little is known about the pathogenic determinants of these pathogens. This research aims at using Ascochyta rabiei as a model for the genus in investigating genetic factors of pathogenicity, with the ultimate goal of elucidating pathogenic mechanisms. Three advances were made: (1) insertional mutants with altered pathogenicity were identified through in vivo screening, and genomic regions adjacent to the insertion sites in selected mutants were determined; (2) a phage library of A. rabiei genomic DNA was constructed, and the library was estimated to provide complete coverage of the A. rabiei genome. This library was used successfully to recover clones with DNA adjacent to insertional mutation sites and to isolate specific genes; (3) DNA probes specific for an acyl-CoA ligase (cps1) and a polyketide synthase gene (pks1) were developed and library clones containing the corresponding genomic regions were identified from the phage library. These advances provide the foundation and necessary tools for experimentation of ectopic complementation assays and targeted mutagenesis to elucidate the genetic mechanisms of pathogenicity of A. rabiei.     

Resistance mechanisms and associated mutations in acetylcholinesterase genes in Sitobion avenae (Fabricius)

Wheat aphid, Sitobion avenae (fabricius), is one of the most important wheat pests and has been reported to be resistant to commonly used insecticides in China. To determine the resistance mechanism, the resistant and susceptible strains were developed in laboratory and comparably studied. A bioassay revealed that the resistant strain showed high resistance to pirimicarb (RR: 161.8), moderate reistance to omethoate (32.5) and monocrotophos (33.5), and low resistance to deltamethrin (6.3) and thiodicarb (5.5). A biochemistry analysis showed that both strains had similar glutathione-S-transferase (GST) activity, but the resistant strain had 3.8-fold higher esterase activity, and its AChE was insensitive to this treatment. The I₅₀ increased by 25.8-, 10.7-, and 10.4-folds for pirimicarb, omethoate, and monocrotophos, respectively, demonstrating that GST had not been involved in the resistance of S. avenae. The enhanced esterase contributed to low level resistance to all the insecticides tested, whereas higher resistance to pirimicarb, omethoate, and monocrotophos mainly depended on AChE insensitivity. However, the AChE of the resistant strain was still sensitive to thiodicarb (1.7-fold). Thus, thiodicarb could be used as substitute for control of the resistant S. avenae in this case. Furthermore, the two different AChE genes cloned from different resistant and susceptible individuals were also compared. Two mutations, L436(336)S in Sa.Ace1 and W516(435)R in Sa.Ace2, were found consistently associated with the insensitivity of AChE. They were thought to be the possible resistance mutations, but further work is needed to confirm this hypothesis.     

The carboxyterminal processing protease of D1 protein: Herbicidal activity of novel inhibitors of the recombinant and native spinach enzymes

The carboxyterminal processing protease of D1 protein (CtpA) is predicted to be an excellent target for the discovery of a general broad-spectrum herbicide. Directed and random screening of compounds against recombinant spinach CtpA (rCtpA) has led to the discovery of five different chemical classes of inhibitors. Lead compounds from each inhibitor class were investigated for their in vitro effects on the activities of both recombinant and native spinach CtpA. All of the lead compounds have K_i values of less than 50 μM when tested against rCtpA, and all except one showed competitive inhibition. Results from partially purified native CtpA from spinach were similar to those from the recombinant form of the enzyme, thus validating the use of rCtpA in the inhibitor screen. Compounds from three of the classes of CtpA inhibitors show in vivo herbicidal activity against Arabidopsis thaliana when applied either by addition to growth media or by spraying the leaves. Transgenic Arabidopsis plants which over-express CtpA showed greater resistance to the compounds than wild-type plants providing evidence that these inhibitors are directly acting against CtpA.     

日粮和管理对东北虎血液指标及免疫功能的影响

从营养和管理方式均不同的两组东北虎群中各选5只体型适中的成年雄性东北虎作为研究对象，其中笼养组以纯肉为日粮，散养组以混合饲料为日粮。麻醉后采集静脉血，测定血液中各项生理生化指标，外周血淋巴细胞增殖性反应，以及血清中白细胞介素-2（IL-2）、白细胞介素-6（IL-6）和肿瘤坏死因子（TNF）的含量。结果：散养组外周血淋巴细胞增殖性反应显著高于笼养组（P〈0．05）；血清尿素、肌酐、淀粉酶、谷丙转氦酶、谷草转氦酶等指标在两组间差异显著（P〈0．05）：全血红细胞计数、白细胞计数、血红蛋白含量、血清蛋白、甘油三酯、总胆固醇等指标组间差异不显著（P〉0．05）。结果显示：营养和管理方式对东北虎某些血液指标产生影响，混合日粮和散养方式更有利于维持东北虎的正常免疫机能和健康。