烟草青枯病生防菌的筛选及其田间防效评价

为筛选出对烟草青枯病有效防治的生防菌,通过稀释涂布法从烟株根际土壤分离到一株具有明显拮抗作用的菌株69-1,经16S rDNA鉴定该菌株为壮观链霉菌(Streptomyces spectabilis),并用该菌株进行烟草青枯病田间防治试验。结果表明,与对照相比,经菌株69-1处理烟株茎围、有效叶片数、最大叶宽、最大叶长、上中下部烟叶单叶干重、最大叶面积、产量均显著增加,且对烟草青枯病的相对防效达60.42%,同时对不同处理组的初烤烟叶进行化学成分的检测分析,发现菌株69-1处理相对于对照组烟叶品质更佳。该菌株菌剂处理不仅可以提高烟株对烟草青枯病的防效,而且还提高烟叶品质和产量,可为烟草青枯病生物防治提供一定参考。     

Enzyme Bioprospection of Marine-Derived Actinobacteria from the Chilean Coast and New Insight in the Mechanism of Keratin Degradation in Streptomyces sp. G11C

Marine actinobacteria are viewed as a promising source of enzymes with potential technological applications. They contribute to the turnover of complex biopolymers, such as pectin, lignocellulose, chitin, and keratin, being able to secrete a wide variety of extracellular enzymes. Among these, keratinases are a valuable alternative for recycling keratin-rich waste, which is generated in large quantities by the poultry industry. In this work, we explored the biocatalytic potential of 75 marine-derived actinobacterial strains, focusing mainly on the search for keratinases. A major part of the strains secreted industrially important enzymes, such as proteases, lipases, cellulases, amylases, and keratinases. Among these, we identified two streptomycete strains that presented great potential for recycling keratin wastes—Streptomyces sp. CHA1 and Streptomyces sp. G11C. Substrate concentration, incubation temperature, and, to a lesser extent, inoculum size were found to be important parameters that influenced the production of keratinolytic enzymes in both strains. In addition, proteomic analysis of culture broths from Streptomyces sp. G11C on turkey feathers showed a high abundance and diversity of peptidases, belonging mainly to the serine and metallo-superfamilies. Two proteases from families S08 and M06 were highly expressed. These results contributed to elucidate the mechanism of keratin degradation mediated by streptomycetes.     

菌剂与钾肥配施对连作魔芋生长、生理代谢和发病率的影响

以安康当地花魔芋为材料进行盆栽试验，研究娄彻氏链霉菌（Streptomyces rochei）菌剂D74与钾肥配施对连作魔芋生物学性状、块茎产量、叶绿素含量、活性氧代谢、渗透调节物质含量及软腐病的影响，为魔芋连作障碍微生物-化学双重修复提供理论依据。结果表明：菌剂与钾肥配施对连作魔芋具有一定的促生防病作用，使魔芋单株块茎鲜质量和生长系数分别较对照显著增加86.7%和85.9%，软腐病病情指数降低 33.0%。配施处理中，钾肥和菌剂分别在促进魔芋块茎膨大和抑制软腐病方面发挥主导作用。菌剂与钾肥配施促进魔芋叶片叶绿素的合成，其叶绿素a及叶绿素(a+b)含量分别较对照显著增加51.0%及34.6%，同时叶绿素a/b及叶绿素(a+b)/类胡萝卜素比值分别提高41.8%及22.2%。配施的菌剂效应对叶绿素合成的促进作用占主导地位。菌剂与钾肥配施显著提高魔芋的诱导抗性，其叶片过氧化物酶活性、可溶性蛋白和可溶性糖含量分别为对照的3.1倍、2.9倍和2.2倍。采用主成分分析法对魔芋相关19个生理生化指标分析得出特征值、贡献率、累积贡献率和主成分载荷矩阵，提取3个主成分（叶绿素b、叶幅和相对防效）综合评价菌剂与钾肥配施对魔芋连作障碍的修复效果。不同施肥处理综合得分高低顺序为：菌剂与钾肥配施>单施钾肥>单施菌剂>不施肥对照。综上所述，娄彻氏链霉菌菌剂D74与钾肥配施能提高连作魔芋产量并降低植株发病率，有效缓解连作障碍。     

链霉菌和壳聚糖对淮山土壤微生物活性与群落的影响

为探究链霉菌30702和壳聚糖对淮山土壤微生物活性与群落的影响,采用比色法和滴定法观测土壤酶活性的变化,采用高通量测序技术和Trimmomatic等软件,分析土壤微生物群落中细菌和真菌的发展变化。结果表明,链霉菌、壳聚糖、土壤原始微生物和培养时间等4个因素对淮山土壤的脲酶和过氧化氢酶活性均有显著影响,壳聚糖浓度在0~10.0 g/kg内,土壤酶活性随壳聚糖浓度的增大而提高;随时间的延长,先升再降;壳聚糖与链霉菌之间存在交互效应。链霉菌和壳聚糖能增加淮山土壤细菌的物种丰度,减少细菌的多样性,增加艾德昂菌属（Ideonella）和纤维弧菌（Cellvibrio）等有益菌属的相对丰度,而对真菌的物种丰度和多样性的影响较小,与对照之间的差异不显著,土壤优势菌属为腐质霉属（Humicola）、枝孢属（Cladosporium）、鞘氨醇单胞菌属（Sphingomonas）和uncultured_bacterium_ c_Subgroup_6。其中,链霉菌与2.5 g/kg壳聚糖复合处理的细菌物种丰度最大,细菌多样性最少。     

丰加霉素对黄瓜立枯丝核菌的拮抗作用

采用菌丝生长速率法和盆栽试验法,研究了淀粉酶产色链霉菌Streptomyces diastatochromogenes胞外代谢产物丰加霉素（toyocamycin）对黄瓜立枯丝核菌Rhizoctonia solani的拮抗作用。结果表明：丰加霉素对立枯丝核菌菌丝生长和菌核形成有明显的抑制作用,抑制菌丝生长的EC50值为1.67mg.L-1,浓度为2.20mg.L-1时能完全抑制菌核形成。盆栽试验结果表明,丰加霉素对黄瓜苗立枯病有明显的保护和治疗作用。喷施19.54mg.L-1丰加霉素14d后,对黄瓜苗立枯病的治疗效果为71.91%,显著高于对照霉灵1000倍液的治疗效果（35.83%）;喷施19.54mg.L-1丰加霉素14d后,预防效果为51.06%,与对照无显著差异。施药后21d和14d的治疗效果和保护效果均相当;同时19.54mg.L-1和9.77mg.L-1的丰加霉素对黄瓜立枯病的作用效果相当。     

Temporal association of potato tuber development with susceptibility to common scab and Streptomyces scabiei‐induced responses in the potato periderm

Using hydroponics and novel non‐destructive pot culture systems which enable inoculation at specific tuber development stages, the dynamics of common scab infection patterns in potato were studied in order to provide more precise identification of tuber physiological factors associated with susceptibility. At the whole‐tuber level, infection percentages were greatest when Streptomyces scabiei inoculation occurred early; at 2 weeks after tuberization (WAT) 68% of tubers became infected, contrasting with late inoculation (8 WAT), when only 4% infection occurred. The first‐formed internodes were most susceptible to infection, whilst later‐forming and slower‐expanding internodes were less susceptible. Detailed tuber physiological examination of internode 2 showed that pathogen‐induced changes, including increased phellem (periderm) thickness, cell layers and phellem suberization (key physiological features believed critical to S. scabiei infection) were promoted through S. scabiei inoculation. Sequential harvesting showed enhanced phellem suberization (28% greater than the control) within 7 days of pathogen exposure, while phellem thickness and layer responses were also initiated early in the infection process (10–14 days after pathogen exposure) and these responses were independent of symptom expression. Differences in cultivar response were observed, with greater phellem suberization observed 10 days after tuberization (DAT) in the common‐scab‐tolerant cv. Russet Burbank than in the susceptible cv. Desiree. Likewise, Russet Burbank had thicker and more numerous cell layers in the phellem (up to eight cell layers) during early tuber growth (20–30 DAT) than Desiree (up to six cell layers).     

番茄叶霉病菌拮抗链霉菌BPS2发酵条件的研究

(1吉林省农业科学院，公主岭 136100；2东北农业大学资源与环境学院，哈尔滨 150030； 3吉林农业大学农学院，长春 130118)     

Transmission of resistance to common scab from the diploid to the tetraploid level via 4x-2x crosses in potatoes

Summary Diploid potato clones selected for their reaction to common scab and their ability to produce 2n male gametes were used in a series of crosses to a susceptible tetraploid female parent (cv. Shepody). In addition, two tetraploid clones were also selected for their reaction to common scab and crossed with Shepody as a female parent. Results indicated that resistance to common scab can be effectively transmitted from the diploid to the tetraploid level via 4x-2x crosses. Diploid parents producing 2n pollen via either first division or second division restitution can be used to transmit scab resistance. A relatively small proportion of resistant individuals could be recovered from susceptible x susceptible crosses in both 4x-2x and 4x-4x combinations. The data support a previously developed hypothesis that scab resistance is relatively simply inherited.     

利迪链霉菌A02诱导番茄抗灰霉病作用机制研究——对植株防御酶系的影响

利用利迪链霉菌生防菌株A02发酵液和番茄灰霉病菌对番茄植株进行诱导和接种处理,利用分光光度法测定处理前和处理后1~5 d番茄叶片组织的主要防御酶系——苯丙氨酸解氨酶、过氧化物酶、过氧化氢酶和多酚氧化酶的活性变化。试验结果显示,不接种灰霉病菌而单独诱导处理、接种灰霉病菌后诱导处理和诱导处理后接种灰霉病菌这3种处理都能提高番茄植株各防御酶系的活性,后者酶活性峰值最高,对番茄植株灰霉病的抑制作用也最明显,控制效果达94.92%。     

一株产抗生素链霉菌的研究初报

从土壤中筛选出一株能产生抗生素的放线菌,经鉴定为放线菌科链霉菌属。抗菌谱分析表明,该菌株对革兰氏阴性细菌抗性较弱,对革兰氏阳性细菌有较强的抗性,对含芽孢细菌抑菌效果尤为明显。其活性成分能耐受100℃、120min水浴,且具有一定的耐酸能力。