细菌在植物病害生防中的

1、细菌在植物病害生防中的应用进展1细菌是植物根围优势微生物类群The Rhizosphere is the zone surrounding the roots of a plant which complex relations exists among the plant, the soil microorganisms and the soil itself. The plant roots and the biofilm associated with them can profoundly influence the chemistry of the soil including pH

2、 and nitrogen transformations.2一、细菌作为生防菌的优势细菌单细胞，便于进行规模发酵生产（模仿Bt生产工艺）生长繁殖，便于进行制剂生产芽孢杆菌存活时间长，便于制剂储存3二、细菌防治植物病害的机制抗生作用寄生作用竞争作用诱导植物抗性4Agrobacterium radiobacter K84 production of Agrocin 84 (bacterocin) inhibiting just A. tumefaciens细菌的抗生作用5细菌的寄生作用细菌寄生线虫 如穿透巴氏杆菌（Pasturia penetrens）寄生线虫6再如：蛭弧菌寄生G-细菌7 此外，

3、链霉菌（放线菌）对真菌具有重寄生作用 例如：链霉菌菌株F46和PR在灰葡萄孢菌丝上产生附着胞、缠绕靶标菌丝, 使靶标菌丝畸形等现象。8诱导抗性激活植物的防卫反应 如防卫反应相关酶（POD、PPL、PPO）等活性提高、产生植保素和PR蛋白等 系统性诱导抗性可用于防治植物地上部分病害。9三、商品制剂10植物种苗的细菌化（Bacterization）以细菌粘着剂（如Pelgel）包衣植物种子或苗木 促进植物生长 防治根部病害 处理方便，易商品化11121314利用芽孢杆菌防治桃褐腐病的效果细菌处理对照处理15ManufactureTrade namesTargeted diseaseApplied

4、cropsReferencesGustafson, USAQuantum, Kodiak & StealthSeedling & soil borne diseaseCotton, peanut & vegetablesLisansky et al., 1995Gustafson, USAKodiak ATSeedling & Soil borne diseasesCotton, peanut,cereals & legumesLisansky et al., 1995Agraquest, USASerenadeFungal & bacterial foliar diseasesGrapevi

5、ne fruit trees & vegetables. comMicroBio, EnglandEpicRoot diseasesCotton, peanut & beanLisansky et al., 1995Novosibirsk, RussiaBactophytFungal & bacterial diseasesVegetables & cereals Lisansky et al., 1995Bayer AG, Germany FZB 24Seedling & Soil borne diseasesVegetables, potato & tobacco Junge et al.

6、, 2000Kilian et al., 2000Commercial biopesticides based on formulation of Bacillus subtilis161718Development of Streptomyces as a biofungicide and its applicationStreptomyces Gram positive mostly saprophytic aerobic soilborne well-adapted to high temperature grows well in slightly alkaline environme

7、nt produce antibiotics & hydrolytic enzymes19Important antibiotics Streptomycin (bacterial diseases of fruits) Kasugamycin & Blasticidin S (rice blast) Polyoxin & validamycin (rice sheath blight) New antibiotics (soilborne diseases) Chitinase (soilborne diseases)20Formulation of biomass MycostopTM P

8、roduced by S. griseovirides Effective against Botrytis cinerea on lettuce, Fusarium oxusporum on carnation, Alternaria sp. on cauliflower, Pythium sp. on sugar beet and curcurbits 21Streptomyces saraceticus SS31 effective for root knot nematode chitinase also antagonistic to fungal pathogens, especi

9、ally to Oomycetes on solid substrate, spore yield can reach up to 1011cfu/g shelf life: 1 year at 8 C a soil amendment containing mushroom compost, fish meal, crab shell powder and rapeseed pomace can enhance proliferation of SS31 in liquid production system, corn starch and soluble chitin was used

10、as major culture substrate. Biomass yield can reach up to 109- 1010 cfu/mL effective to control Phytophthora infestans on papaya (5% via 30% in untreated plants) significantly reduced incidence of damping-off of cucumber (Pythium aphanidermatum)22Research methodology for soilborne plant pathogensMic

11、roorganism isolation ScreeningEfficacy testingIdentity characterizationMechanism exploitationToxicitiy testingMass production, formulation and commercialization23Microorganism isolationSample collection soil samples from various ecological niches plant rhizoplane & rhizosphere soil plant roots 24Iso

12、lation methods direct isolation dilution platings tissue plating (endophytes) indirect isolation baiting technique with sclerotia with senescent plant tissue 25Soil samples should collected fertile fields or rhizosphere disease suppressive soils forest soils sea water in a word, from an alien ecolog

13、ical niche, you may have more chance to get new strains 26In order to obtained diversified species, we should change media and incubation conditions different media support growth of different microorganisms different incubation conditions favor growth of also different species 27For isolating bacte

14、ria, nutrient agar (NA) and Kings B media are conventional used Fluorescent pseudomonads produce fluorescent substances on Kings B media, Therefore, this media can be used for preliminary identification of bacterial strains Incubation in water at 80C may help to isolate Bacillus species 2829For isol

15、ating Streptomyces, media containing soluble starch are more suitable 30For isolating fungi, potato dextrose agar (PDA) amended with streptomycin or lactic acid is generally used.31For isolating plant endophytes, plant tissues should be surface sterilized before isolation This is a hot research fiel

16、d!32ScreeningThe most important thing is to establish a screening system antibiotics-production hyperparasitism competition predation plant growth promotion33We should consider: characteristics of the target pathogens how to get the candidate strains and pathogens involved in interaction how to mass

17、 screen34Generally, in vitro screening is used firstlyFollowed by potting experiments field microplot experiments field macroplot experiments characterization of biological fitness sometimes, effective antagonism cannot confer efficient biological control in soil or on plants 35For screening plant g

18、rowth-promoting strains, potting experiments are of the foremost importance36Identity characterizationMorphology somatic cells, spores, colonyPhysiological and biochemical characterization production of specific substances,utilization of specific carbon/nitrogen Molecular characterization cloning, sequencing and comparison of specific genes 37Mechanism exploitationFrom screening procedures, some mechanisms can be deduced, how