芽孢杆菌绿色荧光蛋白标记及其在小麦体表定殖的初探

 将来自质粒pAD4412的启动子和绿色荧光蛋白基因gfpmut3a插入大肠杆菌-枯草芽孢杆菌穿梭载体pBE2,构建成芽孢杆菌表达载体pGF P4412,用其转化野生型生防芽孢杆菌83-6和A-47等8个菌株,均得到良好的发光表型。质粒稳定性实验表明重组质粒pG FP4412稳定性为92%。借助荧光显微镜对gfp标记的菌株A-47-gfp在小麦体表的定殖进行初步的研究。结果表明:A-47-gfp能够在小麦根际及小麦体表定殖(包括根表和茎叶表面);相对于在茎叶表面定殖的A-47-gf p在根表定殖的菌体与根的结合更为牢固;从根基到根尖A-47-gfp的定殖量有明显的减少趋势。     

Endophytic-Host Selectivity of Discula umbrinella on Quercus alba and Quercus rubra Characterized by Infection, Pathogenicity and Mycelial Compatibility

The fungal endophytic–host relationships of Discula umbrinella and two oak species, Quercus alba and Quercus rubra, were characterized on the basis of endophytic infection, pathogenicity, and mycelial compatibility. Isolates of D. umbrinella were cultured from leaves of Q. alba and Q. rubra collected from a hardwood forest located in Patuxent Wildlife Research Center in Laurel, Maryland, USA. Endophytic infection was observed on sterile leaf discs and living 2-month-old seedlings of Q. alba and Q. rubra. Fungal-host reciprocal inoculations revealed the presence of conidiomata on both hosts but conidiomata production was more abundant on Q. alba. Isolates from Q. rubra produced milder disease symptoms on both oak species. Mycelial compatibility studies identified seven different MCG groups. MCG groups 1–3 contained isolates from both oak species whereas MCG groups 4–7 contained host specific isolates. Field studies monitored the seasonal appearance of the sexual fruiting structures, perithecia, as a possible source of new genetic variation that might alter host specificity/pathogenicity of the D. umbrinella isolates on Q. alba and Q. rubra hosts. Only 1–2% of the leaves contained perithecia throughout the sampling period (April–September). Isolates collected from Q. alba differed from those collected from Q. rubra in endophytic infection, pathogenic response, and perithecia production. The results of this study suggest that the endophyte–host relationship is one of host selective preference for Q. alba, but that the endophyte has the ability to maintain the endophytic/pathogenic life cycle on the less preferred host species, Q. rubra.     

2株重组根瘤菌在4个大豆品种根圈中定殖动态的比较研究

在灭菌和未灭菌土盆栽缩影条件下，比较研究了重组大豆根瘤菌HN01DL和TA113QD在4个不同品种大豆根圈中的定殖动态与水平，并初步考察了其与共生效应的关系。结果表明：HN01DL在渝豆1号和宁镇1号大豆根圈表现出较强的适应性和竞争性，而TA113QD则在Williams大豆根圈的适应性较强，在宁镇1号大豆根圈的适应性较差，且供试菌在4种大豆根圈定殖动态与水平的差异在共生效应上也有一定程度的反映，但未达到显著水平。     

毛乌素沙地3种豆科植物根际AM真菌生态分布研究

通过对毛乌素沙地草木樨(Melilotus suaveolens)、胡枝子(Leapedeza bicolor)和沙打旺(Astragalus adsurgens)等3种豆科植物根际土壤样品和根样的采集和分析,研究了3种植物根际AM真菌的群落组成和生态分布.试验结果表明,在已分离出的3属28种AM真菌中,球囊霉属(Glomus)种类占绝对优势;3种豆科植物都有较高的AM真菌定殖率和孢子密度,但不同种之间或同一种植物在不同样地之间的AM真菌种类和分布差异显著.AM真菌泡囊定殖率和总定殖率与土壤速效N有显著负相关,其定殖强度可能主要取决于宿主植物和AM真菌的相互选择性.     

Effect of Arbuscular Mycorrhizal Fungi and Phosphate-Solubilizing Bacteria Consortia Associated with Phospho-Compost on Phosphorus Solubilization and Growth of Tomato Seedlings (Solanum lycopersicum L.)

ABSTRACT

The exploitation of phosphate mines generates an important quantity of phosphate sludge that remains accumulated and not valorized. In this context, composting with organic matter and rhizospheric microorganisms offers an interesting alternative and that is more sustainable for agriculture. This work aims to investigate the synergetic effect of arbuscular mycorrhizal fungi (AMF), phosphate-solubilizing bacteria (PSB) and phospho-compost (PC), produced from phosphate-laundered sludge and organic wastes, and their combination on plant growth, phosphorus solubilization and phosphatase activities (alkaline and acid). Inoculated mycorrhizae and bacteria strains used in this study were selected from plant rhizosphere grown on phosphate-laundered sludge. Significant (p < .05) increases in plant growth was observed when inoculated with both consortia and PC (PC+ PSB+ AMF) similar to those recorded in plants amended with chemical fertilizer. Tripartite inoculated tomato had a significantly (p < .05) higher shoot height; shoot and root dry weight, root colonization and available P content, than the control. Co-inoculation with PC and AMF greatly increased alkaline phosphatase activity and the rate of mycorrhizal intensity. We conclude that PC and endophytic AMF and PSB consortia contribute to a tripartite inoculation in tomato seedlings and are coordinately involved in plant growth and phosphorus solubilization. These results open up promising prospects for using formulate phospho-compost enriched with phosphorus-solubilizing microorganisms (PSM) in crop cultivation as biofertilizers to solve problems of phosphate-laundered sludge accumulation.     

短小芽孢杆菌BX-4抗生素标记及定殖效果研究

为研究短小芽孢杆菌BX-4在作物根际的定殖及防病效果,通过浓度梯度法用氨苄青霉素对其进行了抗性标记,并通过番茄盆栽试验研究了其在根际土壤中的定殖规律。结果表明,筛选出的突变体菌株BX-4＇能够耐受浓度为200 μg·mL^-1的氨苄青霉素,并且具有耐药和遗传双重稳定性;应用试验显示该突变体菌株能成功在番茄根际定殖,接种20 d后根际土壤中存活数量达到最高值1.34×10^8 cfu·g^-1干土,以后逐渐下降,到50 d时趋于稳定;筛选的突变体菌株对番茄青枯病具有明显的防治效果,防效达37.9%-50.9%。短小芽孢杆菌BX-4在作物根部的定殖规律为揭示其生防机理及应用该菌提供了科学根据。     

棉花黄萎病拮抗细菌HMB-1005鉴定及定殖

以大丽轮枝菌(Verticillium dahliae)为指示菌,对从棉田土壤中已经分离筛选到的细菌HMB-1005进行形态、19项生理生化特征及16S rDNA试验,结果表明,HMB-1005为解淀粉芽孢杆菌(Bacillus amyloliquefaciens);通过灭菌土和非灭菌土进行盆栽试验,拮抗菌HMB-1005芽孢液浸种、土壤全部混菌和部分混菌3种处理,经过5个月的盆栽试验表明,拮抗细菌HMB-1005能够在灭菌土和非灭菌土中定殖,且定殖数量达106cfu/g土左右,并仍能保持较高的抑菌活性。通过对棉苗根内细菌的分离,证实拮抗细菌HMB-1005能在棉花根内定殖,数量达到103cfu/g。实验结果显示,灭菌土的拮抗菌数高于非灭菌土,并且3种处理方式差异不明显,在实际生产应用中,建议使用浸种方法。     

Arbuscular mycorrhizal fungi improve the growth and phosphorus uptake of mung bean plants fertilized with composted rock phosphate fed dung in alkaline soil environment

Abstract

Inoculation effect of arbuscular mycorrhizal fungi (AMF) on phosphorus (P) transfer from composted dung of cattle with a diet supplemented with powdered rock phosphate (RP) and their successive uptake by mung bean plants was assessed in alkaline soil. The efficacy of composted RP fed dung alone or/and in combination with AMF inoculums containing six different species were compared with SSP in six replicates per treatment in pots. The results showed that the association of AMF with composted RP fed dung had a positive effect on mung bean shoot (3.04?g) and root (2.62?g) biomass, chlorophyll (a, b), carotenoid contents and N (58.38?mg plant^?1) and P (4.61?mg plant^?1) uptake. Similarly, the percent roots colonization (56%) and nodulation of mung bean plant roots and their post-harvest soil properties were also improved by the inoculation of AMF together with composted RP fed dung. It is concluded that the combined application of AMF with composted RP fed dung has almost the same effect as SSP for improving mung bean plants growth and their nutrients uptake. Moreover, AMF inoculants can be used as a suitable biofertilizer in combination with locally available organic sources of fertilizers for improving P status and growth of plants in alkaline soils.     

Mycorrhizal inoculation enhances growth and nutrition of cotton plant

Arbuscular Mycorrhizae Fungi (AMF) inoculations may improve growth and nutrient uptake of cotton (Gossypium hirsutum L.) plant. Although the importance of mycorrhizal symbioses for growth and nutrient acquisition of cotton plant is known, less is known about mycorrhizal dependency on P and Zn nutrition under low Zn fertile soil conditions. A greenhouse experiment was conducted to investigate the effect of different of P and Zn fertilizer addition on cotton plant growth as well as Zn and P uptake. Sterilized and non-sterilized low Zn fertile Konya series soil was treated with different levels of P and Zn. Soils were inoculated with two mycorrhizae species like Funneliformis mosseae and Claroideoglomus etunicatum after sterilization. Results showed that mycorrhizal inoculation on plant growth and nutrient uptake has significant effect when soil was sterilized. Cl. etunicatum mycorrhizae species has greater effect than Fu. mosseae mycorrhizae species. Root colonization increased 23–65% due to mycorrhizal amendment. The shoot: root ratio increased by 13 and 22% for non-sterile and sterile condition respectively in mycorrhiza amended soil. Mycorrhizal dependency varies 1–55% and 3–64% for non-sterile and sterile soil respectively on mycorrhizae, P and Zn amended soil. Mycorrhizal dependency analysis showed that cotton plant in both sterile and non-sterile soil conditions depends on mycorrhizae species, P nutrition, however is less depend on Zn nutrition. This study concluded that the inoculation of cotton plant with selected mycorrhizae is necessary under both sterile and non-sterile soil conditions.     

AM真菌对田间山银花生长、矿质营养及绿原酸含量的影响

Lonicera confusa, a traditional Chinese medicine herb for treating cold, flu, acute fever, and so forth, is often grown artificially in acidic soils and suffers from phosphorus (P) deficiency. A five-year field experiment was carried out to study the colonization rate, growth, nutrition, and chlorogenic acid content of Lonicera confusa seedlings inoculated with arbuscular mycorrhizal (AM) fungi, Glomus etunicatum and Glomus intraradices. Before transplanting into a field, both AM-inoculated and uninoculated control plants were cultured in nursery beds. In the plants inoculated with the AM fungi, the colonization rate decreased linearly with time and a greater decrease was observed in the plants inoculated with G. intraradices than with G. etunicatum, while the AM colonization increased from 0% to 12.1% in the uninoculated control plants 5 years after transplanting. Plant height, crown diameter, number of new branches, and flower yield increased significantly by AM inoculation as compared to the uninoculated control. Phosphorus concentrations in leaves and flowers increased, and plant uptake of nutrients, e.g., nitrogen (N), P, and potassium (K), was also enhanced significantly by AM inoculation. The Lonicera confusa seedlings had a better response to inoculation of G. intraradices than G. etunicatum in both growth and chlorogenic acid content in flowers. In contrast, both plant P uptake and P concentrations in leaves and flowers were similar between two fungal inoculations. The positive responses of Lonicera confusa to AM inoculation in growth, nutrient uptake, flowering, and chlorogenic acid content in flowers suggested that AM inoculation in nursery beds could promote the plant growth and increase chlorogenic acid content in flowers of Lonicera confusa when grown on acidic and P-deficient soils.