西瓜内生枯草芽孢杆菌BS211的拮抗活性及盆栽防效

对从西瓜植株体内分离得到的内生拮抗枯草芽孢杆菌BS211的抗菌谱进行了测定;用5种培养基对BS211菌进行培养,测定了这5种BS211菌培养液无菌滤液的抑菌活性;采用硫酸铵沉淀法提取BS211菌抗菌粗提物,并测定了抗菌粗提物的抑菌活性和温度稳定性;运用砂培和盆栽方法进行BS211菌对西瓜枯萎病的防效试验;测定了BS211菌的宿主范围。结果表明:BS211菌对西瓜枯萎病菌等12种病菌都具有强烈的拮抗作用,而且拮抗性能稳定;BS211菌在5种培养基中的生长量没有显著差异而且均能产生抗菌物质,但在不同培养基中产生的抗菌物质的抑菌能力有差异;BS211菌液的硫酸铵沉淀物及上清液对不同病菌的抗性存在差异,说明BS211菌株产生的抗菌物质为复合物;BS211菌抗菌粗提物具有较好的温度稳定性,尤其是硫酸铵沉淀的上清液部分经121℃处理30 m in后活性无明显变化,对番茄青枯病菌仍有强烈的抑菌作用;BS211菌对西瓜枯萎病有显著防效;BS211菌能在辣椒等多种作物体内定殖,有较强的宿主适应性。     

Colonization and degradation of senescent flowers of zucchini squash by Trichoderma harzianum YC459, a biocontrol agent of gray mold, Botrytis cinerea

In commercial greenhouses, senescent flower petals or flowers of vegetables such as tomato, strawberry, hot pepper and zucchini squash were blighted to be removed from fruits within five days after spraying of Trichoderma harzianum YC459 (TORY, JGreen Inc.), a biocontrol agent with good and consistent efficacy as chemical fungicides for the control of gray mold rot caused by B. cinerea. The mechanism for selective colonization of senescent floral tissues by T. harzianum YC459 was …     

Actinobacteria-enhanced plant growth, nutrient acquisition, and crop protection: Advances in soil, plant, and microbial multifactorial interactions

Agricultural areas of land are deteriorating every day owing to population increase, rapid urbanization, and industrialization. To feed today’s huge populations, increased crop production is required from smaller areas, which warrants the continuous application of high doses of inorganic fertilizers to agricultural land. These cause damage to soil health and, therefore, nutrient imbalance conditions in arable soils. Under these conditions, the benefits of microbial inoculants (such as Actinobacteria) as replacements for harmful chemicals and promoting ecofriendly sustainable farming practices have been made clear through recent technological advances. There are multifunctional traits involved in the production of different types of bioactive compounds responsible for plant growth promotion, and the biocontrol of phytopathogens has reduced the use of chemical fertilizers and pesticides. There are some well-known groups of nitrogen-fixing Actinobacteria, such as Frankia, which undergo mutualism with plants and offer enhanced symbiotic trade-offs.In addition to nitrogen fixation, increasing availability of major plant nutrients in soil due to the solubilization of immobilized forms of phosphorus and potassium compounds, production of phytohormones, such as indole-3-acetic acid, indole-3-pyruvic acid, gibberellins, and cytokinins, improving organic matter decomposition by releasing cellulases, xylanase, glucanases, lipases, and proteases, and suppression of soil-borne pathogens by the production of siderophores, ammonia, hydrogen cyanide, and chitinase are important features of Actinobacteria useful for combating biotic and abiotic stresses in plants.The positive influence of Actinobacteria on soil fertility and plant health has motivated us to compile this review of important findings associated with sustaining plant productivity in the long run.     

生防菌粗毒素对猪殃殃防御酶及叶片细胞膜透性的影响

为了揭示生防菌的致病机理,用3株生防菌粗毒素处理猪殃殃叶片,测定其过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、过氧化物酶(POD)的活性、电导率和丙二醛(MDA)含量,探讨生防菌粗毒素对叶片防御酶活性及叶片细胞膜透性的影响。结果表明,3株生防菌粗毒素使猪殃殃叶片组织细胞膜透性上升,MDA含量上升;毒素处理后的猪殃殃叶片中POD、SOD和CAT的活性均较不处理的对照升高。     

香蕉枯萎病内生生防菌H4-3抑菌蛋白稳定性研究

铜绿假单胞菌H4-3菌株是福建省农科院农业生物资源研究所微生物研究中心从香蕉植株中分离到的内生菌,该菌株对香蕉枯萎病原菌具有很强的抑菌活性,其活性物质为大分子蛋白.研究测定了H4-3菌株抑菌蛋白的稳定性,结果表明：H4-3菌株的抑菌蛋白耐高温、强酸、强碱和高浓度蛋白酶,紫外线和反复冻融对H4-3菌株抑菌蛋白活性无显著影响.     

魔芋内生拮抗细菌生防机理研究

对自选魔芋内生拮抗细菌M3、1–7、M2的生防机理进行研究,结果表明,魔芋内生菌M3、1–7、M2具有广谱抗性,3株菌及其代谢粗提物对不同致病力的魔芋软腐病菌均有拮抗作用;3株拮抗菌分别含有不同的抗菌素基因,1–7与魔芋软腐病菌MY9的相似营养系数最高,达90.63%;M3在魔芋根际及体内定殖能力均为最强,可达8.2×107 CFU/g;接种时间、接种量及接种方式对生防效果影响较大,生防效果与拮抗菌接种量呈正相关,接种病原菌前1 d接种拮抗菌生防效果最优,球包衣的防治效果优于灌根,M3包衣防效可达79.15%;施入拮抗菌后,魔芋体内和根际土壤微生物群落对底物代谢碳源利用的丰富度和代谢活性明显提高。     

萝卜软腐病生防菌株Hy11的筛选、鉴定及定殖特性

为探讨银杏内生细菌对萝卜软腐病的防病作用,通过块根接种和温室盆栽试验筛选对萝卜软腐菌Pectobacterium carotovorum subsp.carotovorum具有高效抑制作用的生防菌株,共获得8株拮抗作用较强的内生细菌,其中菌株Hy11抑菌作用明显.对生防菌株Hy11进行了形态观察、生理生化特性测定、16S rDNA和gyrB基因序列分析,并应用绿色荧光蛋白基因标记菌株Hy11,研究该菌株在萝卜体内的定殖动态.结果显示,该菌株对萝卜软腐病具有较好的防效,对萝卜块根和幼苗的防治效果分别为77.9％和66.7％;对萝卜幼苗的促生率达113.28％.经鉴定,菌株Hy11为解淀粉芽胞杆菌Bacillus amyloliquefaciens.标记菌株Hy11-gfp在喷雾接种银杏叶片后0～3 d种群数量呈急剧下降趋势,10d后保持相对稳定;其在萝卜的根、茎和叶中均能够定殖,在根中的定殖数量最高可达1.2×104 CFU/g.     

Control of morningglory species using Fusarium solani and its extracts

Abstract

Natural products of an isolate of Fusarium solani App. & Wr. NRRL 18883 grown on rice medium were discovered to be phytotoxic to morningglory. This isolate was evaluated for biocontrol potential on morningglory species including ivyleaf [Ipomoea hederacea (L.) Jacq.], multicoloured (I. tricolor Cav.), paimleaf (I. wrightii Gray), pitted (I. lacunosa L.), purple moonflower (I. turbinata Lag.), red (I. coccinea L.), sharppod (I. cordatotriloba Dennstedt), smallflower (Jacquemontia tamnifolia (L.) Griseb], and tall [I. purpurea (L.) Roth] morningglory. When sprayed at a concentration of 10 g fungus‐infested rice per 50 ml of water, this isolate caused phytotoxic damage including necrosis, chlorosis, growth inhibition, and mortality. Deleterious effects were recorded in all species, ranging from necrotic spots to death, depending on the species. Mortality ranged from 0% at 3 weeks for purple moonflower to 89% for smallflower morningglory. Soil‐drench application (10–20 ml fungal material per 150 g soil) caused wilting and death. Root lengths of 7‐ and 10‐day‐old plants were reduced between 19 and 89% by soil‐drench application and 17–84% by spray application. Whole plant length reduction of 7‐ and 10‐day‐old plants ranged from 0 to 96%, and 39 to 96% for soil‐drench and spray applications, respectively. Testing of F. solani on weed and crop species showed that most broadleaved species were sensitive but monocotyledons were immune. Tests of the phytotoxic extract for known phytotoxins such as common trichothecene (deoxynivalenol) and non‐trichothecene compounds (fusaric acid, moniliformin, fumonisins) were negative. This is the first report of the use of F. solani against morningglory.     

一种实验室用固态发酵真菌孢子分离装置的研制

为获得高纯度孢子粉,针对生防真菌孢子粒径微小,易悬浮于空气中,利用气旋原理,研制出实验室用固态发酵真菌孢子分离装置.该装置由物料粉碎机、沉降分离器、气流循环系统和风机等构成.100 g 自然阴干的蜡蚧轮枝菌固体发酵培养物,经孢子分离器处理15 min ,分离收获到70%以上的蜡蚧轮枝菌分生孢子,且获得的孢子粉重量占分离前培养物重量的5%.