马铃薯遗传转化体系的优化及玉米淀粉分支酶基因SBEⅡb的导入

以马铃薯脱毒试管苗茎段为转化受体材料,建立并优化了农杆菌介导的马铃薯遗传转化体系。通过农杆菌介导法将玉米淀粉分支酶基因(Starch branching enzyme b,SBEⅡb)的过表达载体转化马铃薯,接种762个茎段,共获得35株抗性植株。经PCR检测获得了4株转基因阳性植株;对转基因植株进一步进行GUS活性组织化学染色,发现转基因植株的茎段与试管薯均被染上蓝色,表明外源SBEⅡb基因已整合到马铃薯基因组,且正常表达。     

Establishment of introduced antagonistic bacteria in the rhizosphere of transgenic potatoes and their effect on the bacterial community

In a field release experiment, rifampicin resistant mutants of two antagonistic plant-associated bacteria were used for seed tuber inoculation of transgenic T4 lysozyme expressing potatoes, transgenic control potatoes and non-transgenic parental potatoes. The T4 lysozyme tolerant Pseudomonas putida QC14-3-8 was originally isolated from the tuber surface (geocaulosphere) of T4 lysozyme producing plants and showed in vitro antibacterial activity to the bacterial pathogen Erwinia carotovora ssp. atroseptica. The T4 lysozyme sensitive Serratia grimesii L16-3-3 was originally isolated from the rhizosphere of parental potatoes and showed in vitro antagonism toward the plant pathogenic fungus Verticillium dahliae. The establishment of the inoculated bacteria in the rhizosphere and geocaulosphere of the different plant lines was monitored over one growing season to assess the effect of T4 lysozyme produced by transgenic potato plants on the survival of both inoculants. Both introduced isolates were able to colonize the rhizo- and geocaulosphere of transgenic plants and non-transgenic parental plants, and established in the rhizosphere at levels of ca. log(10) 5 colony forming units g(-1) fresh weight of root. During flowering of plants, significantly more colony counts of the T4 lysozyme tolerant P. putida were recovered from transgenic T4 lysozyme plants than from the transgenic control and the parental line. At this time, the highest level of T4 lysozyme (% of total soluble protein) was detected. Effects of the inoculants on the indigenous microbial community were monitored by analysis of PCR-amplified fragments of the 16S rRNA genes of the whole bacterial community after separation by denaturing gradient gel electrophoresis (DGGE). At any sampling time, the DGGE pattern of rhizosphere and geocaulosphere communities did not show differences between the inoculated and non-inoculated potatoes. Neither of the introduced strains became a dominant member of the bacterial community. This work was the first approach to assess the establishment of plant growth promoting rhizobacteria and potential biocontrol agents on transgenic plants.     

Effects of rye and triticale seed proteins on Leptinotarsa decemlineata (Say) digestive α-amylase and protease and some biological parameters

The current study aimed to investigate the effect of rye and triticale seed proteins on the Leptinotarsa decemlineata, gut enzymes. Results showed that ammonium sulphate precipitation fractions; 0–30, 30–50, 50–70 and 70–100% had no inhibition on the fourth instar larval (L₄) protease activity, while first two fractions of triticale and all fractions of rye had inhibitory effects on the all larval stages and adult’s α-amylase activity. Mode of inhibition in rye and triticale was partial mixed and uncompetitive, respectively. Zymograms approved the results. Feeding assays were conducted using four cultivars of potato leaves treated with extracts. Weight of L₄ on Marx in both trials and the L₄ evolution in all cultivars in rye and just on Picasso in triticale were reduced, the developmental durations were increased on Marx and Picasso in triticale trial significantly. Also, rye extract caused inhibition in amylase activity of survived individuals that feed from treated Burren leaves.     

Mapping QTLs controlling fruit quality in peach (Prunus persica (L.) Batsch)

 The organoleptic quality of fleshy fruits is in a large part defined by their composition of soluble sugars and organic acids. An F₂ population issuing from a cross between two peach varieties, ‘Ferjalou Jalousia’, a non-acid peach, and ‘Fantasia’, an acid nectarine, was analysed over 2 successive years for agronomic characters and for molecular-marker (isoenzymes, RFLPs, RAPDs, IMAs and AFLPs) segregations. Blooming and maturity dates, as well as productivity, were noted for each tree. Four fruits per tree were analysed at maturity for fresh weight, colour, pH, titratable acidity, soluble-solids content (SSC), acid (malic, citric and quinic acids) and sugar (sucrose, glucose, fructose, sorbitol) contents. QTLs were detected for all fruit components analysed, except for fruit colour. The QTLs for nearly all components were present on two linkage groups. For productivity, fresh weight, pH, quinic acid, sucrose and sorbitol content, all the detected QTLs displayed the same effect as the parental phenotypes. By contrast, for maturity date, titratable acidity, malic and citric acids and fructose, some QTLs displayed the same effect as the parental phenotypes while others displayed the opposite effect. The fraction of the total variation in each trait throughout the population explained by the QTLs was very high and reached more than 90% for some characters. For most of the characters analysed, epistasis was observed between QTLs. Received: 10 October 1997 / Accepted: 18 August 1998     

Comparative structural stability of subunits of the potato virus X coat protein in solution and in virus particles

Several optical methods and differential scanning calorimetry were used to study the structure and stability of free coat protein (CP) molecules and CP molecules in the virion of the potato virus X (PVX), a filamentous plant virus. All criteria suggest that PVX CP (hereinafter, CP) subunits in solution at room temperature display a certain preserved tertiary structure; however, this structure is very unstable and already denatures at 35°C. Very low concentrations of sodium dodecylsulfate or cetyltrimethylammonium bromide also disrupt the CP tertiary structure, three-five molecules of these detergents per one protein molecule being sufficient. However, the secondary structure of CP molecules does not change under the same conditions. Once included into the virion, CP subunits become considerably more stable towards increased temperature and detergents. This combination of a highly labile tertiary structure and a fairly stable secondary structure of free CP can be a structural basis for the recently discovered ability of PVX CP to assume two distinct functional states within the virion.     

微卫星标记及其在蚜虫种群生物学研究中的应用

微卫星（SSR）是以1～6个碱基为重复单位组成的简单串联重复序列,具有丰度高、多态性高、共显性遗传、选择中性和可重复性好等优点。微卫星标记技术可分为三种类型：基于杂交的SSR指纹,基于PCR的SSR指纹和单位点SSR的PCR扩增。前两者不需要知道基因组序列信息,属于多位点标记;后者则需要前期工作,属于单位点标记,即通常所指的微卫星标记。到目前为止,共在14种蚜中筛选到141个微卫星位点,并发表了相关的引物序列,这给今后的相关研究提供了丰富的共享资源。业已证明微卫星引物在邻近种之间有一定的通用性。微卫星标记严格遵守孟德尔遗传规律,已经被用来推断某些蚜虫有性生殖的情况。同种蚜虫中可能同时存在有性系和无性系,微卫星研究证明有性系比无性系有更高的遗传多样性,无性系通常表现出杂合过剩和连锁不平衡。蚜虫的迁飞规律适合用微卫星标记加以研究,已有的研究显示在具有高度迁飞特性的种类中,地理种群间的遗传分化程度低,基因频率的相似性高。存在广泛分布的相同的多位点基因型是迁飞性蚜虫的另一个重要特征。在我国,微卫星应用于蚜虫生物学研究的工作还较少,鉴于该种标记的优良特性和巨大的潜力,本文建议今后相关的研究应该首先考虑微卫星标记。     

Sporulation,storage and infectivity of obligate aphid pathogen Pandora nouryi grown on novel granules of broomcorn millet and polymer gel

Aims: Producing granular cultures of obligate aphid pathogen Pandora nouryi for improved sporulation and storage. Methods and Results: Small millet–gel granules were made of the mixtures of 80–95% millet powder with 5–20% polymer gel (polyacrylamide, polyacrylate or acrylate‐acrylamide copolymer) and inoculated with mycelia at 30 mg biomass g^?1 dry granules plus 87·5% water, followed by static incubation at 20°C for 4–12 days. The fungus grew well on 12 preparations but best on that including 10% copolymer. An 8‐day culture of this preparation discharged maximally 58·5 × 10⁴ conidia mg^?1 granule at 100% RH and was capable of ejecting conidia at the nonsaturated regimes of 86–97% RH. During storage at 6°C, granular cultures with >85% water content had twofold longevity (120 days) and half‐decline period (34–36 days) of those stored at room temperature. The steadily high water content preserved the cultures better than that decreasing at 6°C. However, conidia from 70‐day‐stored granules were less infective to Myzus persicae nymphs than those from fresh ones based on their LC₅₀s. Conclusions: The millet–gel granules had higher sporulation capacity than reported Pandora cultures and a capability of spore discharge at nonsaturated humidity. Significance and Impact of the Study: The granular cultures are more useful for aphid control.     

Role of terpenes from aphid-infested potato on searching and oviposition behavior of Episyrphus balteatus

To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are then able to express traits that facilitate ＂top-down＂ control of pests by attracting herbivore predators. Here we investigate the indirect defence mechanism of potato plants by analyzing the volatile patterns of both healthy and aphid- infested plants. Important changes in the emitted terpene pattern by the Myzus persicae infested host plant were observed. Using Solid Phase MicroExtraction （SPME） and GC-MS, the （E）-fl-farnesene （EBF） appeared to be emitted by aphid-infested potato and not by healthy plants. To assess the infochemical role of these volatile releases after aphid damage on the aphidophagous predators Episyrphus balteams, the hoverfly foraging behavior was assessed using the Observer 5.0 software （Noldus, Wageningen, The Netherlands）. Aphidfree potato plants were also used as a control volatile source in the predator behavioral study. While aphid-infested plants induced efficient searching and acceptation behaviors leading to egg-laying, no kairomonal effect of healthy potato plants was observed, leading to longer immobility durations and shorter searching periods in the net cage. High oviposition rate of E. balteatus was observed when aphid-infested potato was used （mean of 48.9 eggs per laying and per female）. On the other hand, no egg was produced by the hoverfly on healthy aphid-free plants. The E. balteatus foraging and reproductive behaviors according to the volatile emission from aphid-infested plants are discussed in relation to the potential use of active infochemical molecules in integrated aphid pest management.     

大豆蚜的生物学防治技术

大豆蚜AphisglycinesMatsumura是亚洲大豆种植区的一种主要农业害虫。近年来,大豆蚜又先后侵入北美洲和大洋州等地,对当地的大豆生产构成了潜在威胁,正成为一种世界性的农业害虫。文章对大豆蚜的分布、危害、生物学特征、天敌和防治技术等方面的研究现状进行了详细论述。     

Parasitism ofLeptinotarsa decemlineata [Coleoptera: Chrysomelidae] byEdovum puttleri [Hymenoptera: Eulophidae] in different cultivars of eggplant

Experiments were conducted to quantify parasitism of Colorado potato beetle,Leptinotarsa decemlineata (Say), by the egg parasitoid,Edovum puttleri Grissell, on 3 different cultivars of eggplant,Solanum melongena L. Levels of parasitism were higher (P<0.05) on ‘Black Pride’ than on other cultivars. The percentage of egg masses that were parasitized was 1.2-fold higher (P<0.05) on ‘Black Pride’ than on ‘Harris Special’ and ‘White’. The number of eggs per mass that were parasitized was 1.3- and 1.4- fold greater (P<0.05) on ‘Black Pride’ than on ‘Harris Special’ and ‘White’, respectively. The percentage of eggs that were parasitized per mass and percentage of emerged adult parasitoids did not differ (P>0.05) among cultivars; between 2.1- to 2.6- fold more females than males emerged from eggs on all cultivars during the growing season.Edovum puttleri suppressed the 2nd generation ofL. decemlineata on ‘Black Pride’ and ‘Harris Special’, but did not suppress populations on ‘White’.