利用泽兰实蝇控制紫茎泽兰的生防策略研究

本文根据野外泽兰实蝇种群15个世代的调查资料,利用契贝谢夫正交多项式拟合了泽兰实蝇、紫茎泽兰的空间格局。阐明了泽兰实蝇空间格局的序列变化及紫茎泽兰空间格局的特点;揭示了泽兰实蝇空间格局的特点受当地主风及寄主紫茎泽兰空间格局特点的影响;并从最优控制系统的角度对泽兰实蝇-紫茎泽兰系统作了初步探讨。首次提出了最佳释放虫量指标为每条虫占有10条枝条。这些结果为多点释放及定点多次释放泽兰实蝇防治紫茎泽兰这一生防策略提供了理论基础。     

Observations of herbivore attack on garlic mustard (Alliaria petiolata) in Southwestern Ontario, Canada

We have observed what appears to be the first significant report of herbivory of a population of Alliaria petiolata (M. Bieb.) Cavara & Grande (Garlic Mustard) in Canada. Ceutorhynchus erysimi Fabr., Plutella xylostella L. (Diamondback Moth), and Philaenus spumarius (Meadow Spittlebug) were identified attacking, and successfully proceeding through different stages of development on A. petiolata. From the field observations, we hypothesize that these species have recognized A. petiolata as a host and therefore may be candidates for the management of the invasive species.     

Antibacterial activity of guava,moringa, camphor bush and pelargonium extracts against bacterial wilt (Ralstonia pseudosolanacearum sp. nov.) of potato

Bacterial wilt (Ralstonia pseudosolanacearum sp. nov.) is a major disease devastating global potato production. Proposed management options are mostly expensive and ineffective. This has necessitated efforts to develop cheaper and eco-friendly management options such as use of botanicals. Antibacterial activity of ethanol and acetone plant extracts from guava (Psidium guajava), drumstick (Moringa oleifera), camphor bush (Tarchonanthus camphoratus) and pelargonium (Pelargonium zonale) against R. pseudosolanacearum sp. nov. was evaluated in-vitro at a concentration of 100 mg/mL of 1 % Dimethlysulfoxide (DMSO) using disk diffusion technique. The R. pseudosolanacearum sp. nov was isolated from infected haulms collected from potato growing field at the University of Nairobi. The most effective extracts were subjected to further screening at different concentrations to determine their minimum inhibitory concentrations (MICs). All the four plant extracts showed varied antibacterial efficacy. P. zonale leaves extract was the most effective with growth inhibition zone of 18.73 mm and 18.60 mm for ethanol and acetone solvents respectively. The average of growth inhibition zones for each plant extract was not significantly different at p ≤ 0.05 among extraction solvents. The minimum inhibitory concentration (MIC) results showed that antibacterial activity of P. zonale and P. guajava leaf started at 6.25 mg/mL with growth inhibition zones of 7.67 and 8.0 mm for ethanol and acetone solvents respectively. P. zonale and P. guajava leaf extracts exhibited significantly higher antibacterial activity at p ≤ 0.05 compared to other extracts. Thus, further research should be conducted to assess their antibacterial potency against R. pseudosolanacearum sp. nov. both in-vivo and under field condition.     

Efficacy of African weaver ant,Oecophylla longinoda (Hymenoptera: Formicidae) in reducing losses due to frugivorous fruit flies (Diptera: Tephritidae) in smallholder mango production systems in Eastern Tanzania

Fruit flies (Diptera: Tephritidae) are dipteran insects that cause high losses of fruits and vegetables in the tropical and subtropical regions of the world. As quarantine pests, fruit flies affect export markets because trade regulations hamper export of fruits from areas with occurrence of fruit flies. We compared the effectiveness of Oecophylla longinoda with the insecticide; imidacloprid for the control of Bactrocera dorsalis in a 6-year-old orchard of mango cultivar ‘Apple’. Mango samples at different developmental stages were collected between September and November in 2012 and between November 2013 and January 2014 at a three-week interval between sampling dates. Every fruit was cultured in a separate individual plastic container containing approximately 500?g sieved sterilised sand. Three weeks later, larvae and pupae were sieved from sand and counted. In both years, significantly higher (P?<?.0001) incidences and infestation rates were recorded in the control plots when compared to the trees protected with insecticides and O. longinoda. Incidences and infestation rates did not differ significantly (P?>?.05) between insecticide and weaver ants protected fruits, implying that O. longinoda was as effective as imidacloprid in suppressing the population of fruit flies. Peak fruit fly incidences and infestation rates coincided with the ripening stage of mango fruits. Our results have shown that the incidences and infestation rates on incubated mango fruits were lowest in the O. longinoda and the imidacloprid protected trees. Thus, O. longinoda is an effective bio-control agent that could be exploited to serve as a vital Integrated Pest Management component on mango orchards.     

小麦内生细菌的分离及其对小麦纹枯菌的拮抗作用

利用涂布平板法从小麦根系中分离出8株内生细菌,从中筛选出1株对小麦纹枯菌(Rhizoctonia cerealis)具有拮抗作用的内生菌。室内测定该菌株培养液对小麦纹枯病菌的抑制作用,结果发现,小麦纹枯病菌在培养液中生长缓慢,培养6d后菌丝量与对照相比下降了89％,同时发现病菌菌丝生长畸形,出现断裂和细胞壁瓦解。双抗标记法测定该拮抗菌在小麦根系中的定殖情况,发现该菌能够在根系中长期定殖。初步的鉴定结果表明该菌为蜡样芽孢杆菌。     

Advances in research of Achnatherum inebrians-Epichloë endophyte symbionts北大核心CSCD

Research on drunken horse grass (Achnatherum inebrians)-endophytic fungi (Epichloë gansuensis, E. inebrians) represented an important area of endophyte research in China. Compared with tall fescue (Festuca arundinacea)-endophyte (E. coenophiala) in the United States and perennial ryegrass (Lolium perenne)-endophyte (E. festucae var. lolii) in New Zealand, A. inebrians-endophyte research in China is becoming a leading branch of endophyte research. The studies of A. inebrians-endophyte symbionts over the past three decades were reviewed, mainly including endophyte distribution, detection methods, infection rate, fungal diversity, stress tolerances of drought, cold, salt, heavy metal, pest, disease and their mechanisms, secondary metabolite of alkaloids, feeding experiments and its ecological functions etc. Research reveals that drunken horse grass itself has no toxicity, the grazed animals will be intoxicated if the grass bears infection by Epichloë endophytes and produces ergot alkaloids. Future research will focus on E. gansuensis and E. inebrians genomics and endophyte functions. In other research we will create new grass cultivars that are 1) sanitized of the endophyte and non-toxic, 2) utilizing novel endophytes that deter birds feeding and 3) utilizing endophytes that are modified to produce novel fungicides, pesticides or medicines. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All rights reserved.     

Proteomics of methyl jasmonate induced defense response in maize leaves against Asian corn borer

Background

Jasmonic acid (JA) and methyl jasmonate (MeJA) regulate plant development, resistance to stress, and insect attack by inducing specific gene expression. However, little is known about the mechanism of plant defense against herbivore attack at a protein level. Using a high-resolution 2-D gel, we identified 62 MeJA-responsive proteins and measured protein expression level changes.

Results

Among these 62 proteins, 43 proteins levels were increased while 11 proteins were decreased. We also found eight proteins uniquely expressed in response to MeJA treatment. Data are available via ProteomeXchange with identifier PXD001793. The proteins identified in this study have important biological functions including photosynthesis and energy related proteins (38.4%), protein folding, degradation and regulated proteins (15.0%), stress and defense regulated proteins (11.7%), and redox-responsive proteins (8.3%). The expression levels of four important genes were determined by qRT-PCR analysis. The expression levels of these proteins did not correlate well with their translation levels. To test the defense functions of the differentially expressed proteins, expression vectors of four protein coding genes were constructed to express in-fusion proteins in E. coli. The expressed proteins were used to feed Ostrinia furnacalis, the Asian corn borer (ACB). Our results demonstrated that the recombinant proteins of pathogenesis-related protein 1 (PR1) and thioredoxin M-type, chloroplastic precursor (TRXM) showed the significant inhibition on the development of larvae and pupae.

Conclusions

We found MeJA could not only induce plant defense mechanisms to insects, it also enhanced toxic protein production that potentially can be used for bio-control of ACB.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1363-1) contains supplementary material, which is available to authorized users.     

植物伴生细菌数量应答系统的研究进展*

N-酰基高丝氨酸内酯(AHLs)作为信号分子介导的细菌数量应答系统参与许多生物学功能的调节,当侵染动植物寄主组织的病原菌繁殖到一定量时,细菌本身产生的AHLs积累到临界浓度,AHLs与胞内特异受体结合,启动致病因子的表达。利用AIRs降解酶和AHLs类似物的特性,干扰和破坏病原菌的AHLs数量应答系统,将为利用现代生物技术防治细菌病害开辟了一条全新的途径。     

Distribution of Catenaria anguillulae Sorokin,a facultative endoparasite of nematodes in soils from different locations of India

A survey of soils from 39 different locations from 12 states of India for the presence/absence of Catenaria anguillulae indicated a wide distribution of the fungus in Indian soils. Out of 490 soil samples, 451 yielded C. anguillulae. Further, it was also noted that the fungus is present throughout the year in soils from the different locations irrespective of soil types and crops grown. This is the first report of this kind on distribution of C. anguillulae from India.     

Fungal endophyte effects on invasive Phragmites australis performance in field and growth chamber environments

Manipulating plant microbiomes may provide control of invasive species. Invasive Phragmites australis has spread rapidly in North American wetlands, causing significant declines in native biodiversity. To test microbiome effects on host growth, we inoculated four common fungal endophytes into replicated Phragmites genotypes and monitored their growth in field and growth chamber environments. Inoculations were highly successful in the growth chamber but inoculated plants in the field were rapidly colonized by diverse endophytes from the local environment. There were significant genotype effects and minimal inoculation effects in both experiments with a significant inoculation × genotype interaction on tiller height in the field. Our results demonstrate that endophyte inoculation treatments are feasible, but repeated inoculations may be required to maintain high titer in plants subject to endophyte colonization from the local environment. Future studies should investigate a wider range of fungal endophytes to identify taxa that inhibit Phragmites and other invaders.