Isolation and characterization of novel soilborne lytic bacteriophages infecting Dickeya spp. biovar 3 (‘D. solani’)

Nine bacteriophages infecting Dickeya spp. biovar 3 (‘Dickeya solani’) were isolated from soil samples collected in different regions in Poland. The phages have a typical morphology of the members of the order Caudovirales, family Myoviridae, with a head diameter of c. 90–100 nm and tail length of c. 120–140 nm. In host range experiments, phage ?D5 expressed the broadest host range, infecting members of all Dickeya spp., and phage ?D7 showed the narrowest host range, infecting isolates of Dickeya dadantii and ‘D. solani’ only. None of the phages was able to infect Pectobacterium spp. isolates. All phages were prone to inactivation by pH 2, temperature of 85°C and by UV illumination for 10 min (50 mJ cm^?2). Additionally, phages ?D1, ?D10 and ?D11 were inactivated by 5 m NaCl and phage ?D2 was inactivated by chloroform. Phages ?D1, ?D5, ?D7 and ?D10 were characterized for optimal multiplicity of infection and the rate of adsorption to the bacterial cells. The latent period was 30 min for ?D1, 40 min for ?D5, 20–30 min for ?D7 and 40 min for ?D10. The estimated burst size was c. 100 plaque‐forming units per infected cell. The bacteriophages were able to completely stop the growth of ‘D. solani’ in vitro and to protect potato tuber tissue from maceration caused by the bacteria. The potential use of bacteriophages for the biocontrol of biovar 3 Dickeya spp. in potato is discussed.     

臭氧结合拮抗酵母对草莓采后灰霉病的控制

为了寻找一种能够代替化学杀菌剂控制草莓采后病害的方法,试验研究了臭氧与罗伦隐球酵母（Cryptococcus laurentii (Ku?erath) Skinner）结合使用对草莓采后灰霉病的控制效果的影响。研究表明,臭氧处理能显著降低草莓采后灰霉病发病率、抑制草莓水果伤口处致病菌数目和抑制霉菌孢子的萌发。经过2 d的贮藏,臭氧处理与罗伦隐球酵母结合使用草莓灰霉病的发病率为29.63%,显著低于对照处理（70.37%）,同时也低于臭氧处理及罗伦隐球酵母单独处理的发病率（分别为48.15%和44.44%）。在20℃和4℃下培养,罗伦隐球酵母在水果伤口处能迅速地增长,并持续保持较高水平。臭氧处理与罗伦隐球酵母结合处理能诱导草莓果实的多酚氧化酶（PPO）、过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）、过氧化氢酶（CAT）和b-1,3-葡聚糖酶（GLU）活性的提高,同时可以抑制脂氧合酶（LOX）活性的增加。     

天津地区草坪草褐斑病菌生物学特性及生物防治

以纯化的草坪褐斑病病原RH2 Rhizoctonia solani为试验菌株,对其生长的温度、pH值、碳源等生物学特性进行研究,并针对目前化学药剂频繁使用的现状,对生产上经常使用的生防药剂进行室内筛选。生物学特性研究表明：褐斑病菌生长适宜温度约30 ℃,适宜pH值6.5～7.5,适宜碳源为蔗糖、可溶性淀粉或乳糖。室内7种生防药剂筛选表明：尼索和特立克的抑菌效果最好,盆栽防治试验结果表明,尼索1 500倍处理防效为72.51％,特立克600倍防效为76.94％。     

Microalgal bioinoculants for sustainable agriculture and their interactions with soil biotic and abiotic components: A review

Modern agricultural practices have posed a detrimental impact on the environment due to their intensive use to meet the food demands of an ever-increasing population. In this context, microalgal bioinoculants, specifically cyanobacteria and green microalgae, have emerged as sustainable options for agricultural practices to improve soil organic carbon, nutrient availability, microbial quality, and plant productivity. An overview of current and future perspectives on the use of microalgal bioinoculants in agriculture practices is presented in this review, along with a discussion of their interactions with soil biotic and abiotic factors that affect soil fertility, plant health, and crop productivity. The benefits of microalgal bioinoculants include releasing agronomically important metabolites (exopolymers and phytohormones) as well as solubilizing soil nutrients. Furthermore, they function as biocontrol agents against soil-borne pathogens and facilitate the establishment of rhizosphere communities of agricultural importance. So far, very few studies have explored the basic mechanisms by which microalgal bioinoculants interact with soil biotic and abiotic factors. In recent years, advanced molecular techniques have contributed to a better understanding of these interactions.     

荔枝采后病害的生物防治研究进展

简要介绍了国内外已筛选出的荔枝采后病害拮抗微生物的种类及其生物防治途径,并对拮抗菌的抑菌机理研究情况进行综述。同时,对我国荔枝采后病害生物防治的现状与存在的问题及今后该领域的发展方向也进行了阐述。     

复合生防菌群对连作土壤大豆根际可培养微生物区系的影响

土壤微生物区系的变化是引起大豆连作障碍的主要因素之一。本实验采用盆栽试验,研究了复合生防菌群对大豆根际土壤可培养微生物区系的调节作用。结果表明,复合生防菌群可以明显改变大豆根际微生物区系组成。在大豆不同时期,复合生防菌群处理的大豆根际细菌、真菌和放线在数量发生较大改变。在大豆真叶期和复叶期,复合生防菌群接种处理大豆根际细菌较对照增幅分别达到71.8%和114.3%,而根际真菌较对照减少12.9%和22.3%.。在大豆真叶期,复合生防菌群接种处理大豆根际放线菌数量较对照减少9.9%,而在复叶期,根际放线数量较对照增加27.4%。此外,研究结显示,施用复合生防菌可有效降低土传病原菌镰孢菌属（Fusarium）和丝核菌属（Rhizoctonia）的比例,并且提高根瘤菌（Rhizobium）、固氮菌（Azotobacter）、木霉属（Trichoderma）、假单胞菌属（Pseudomonas）和芽孢杆菌属(Bacillus)等有益菌的比例。总之,该复合生防菌群对改善连作土壤大豆根际微生物区系方面有良好的效果。     

枯草芽孢杆菌Bs2004菌株的防病促生效果

本文测定了枯草芽孢杆菌Bs2004菌株对生姜姜瘟、大白菜根肿病和莴苣霜霉病的田间防治效果及对作物的促生作用。结果显示:Bs2004菌剂可以显著降低生姜因姜瘟导致的死亡率,并使姜苗和生姜分别增产52.5%、51.2%;对大白菜根肿病的防效达到52.3%,增产14.7%,显著优于庄伯伯和生石灰土壤处理;对莴苣的增产和霜霉病的防治效果与施药次数和施药浓度有一定关系,在莴苣生长前期和中期用药可提高对霜霉病的防治效果,防效达到69.0%,生长后期一次性高浓度用药,莴苣增产效果明显。     

基于防御酶活性分析准噶尔乌头拮抗内生菌对玉米斑点病菌的抑制作用

[目的]活体水平验证新疆准噶尔乌头(Aconitum soongaricum Stapf)拮抗内生细菌XJAS-ZB-14代谢物对两种玉米斑点病菌的抑制活性.[方法]做活体实验,制备玉米叶片酶粗提物,测定叶片总蛋白含量,对比分析来自不同处理组酶粗提液的超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APx)、过氧化氢酶(CAT)等抗病相关防卫酶系活性变化.用Graphpad Prism 5.0统计软件在α=0.01水平进行单因素方差分析.[结果]不同处理组玉米叶片总蛋白含量和各防御酶活性呈不同的变化趋势,XJASZB-14代谢物对玉米大斑病菌和玉米小斑病菌的防效率分别达32.48;和65.16;.[结论]该菌株发酵液有对玉米大、小斑点病菌有较强的抑杀作用.在玉米大、小斑点病菌的生物防治中具有较好的应用价值.     

鲜枣采后生防菌株梅奇酵母XY201培养条件的优化

梅奇酵母（Metschnikowia zizyphicola）XY201是从冬枣表面分离筛选的新酵母菌种,对采后冬枣病原菌具有很好的抑制作用。本试验研究了该酵母菌对碳源、氮源和无机盐的利用情况,以及温度、初始pH和接种浓度三个因素对梅奇酵母生物量的影响,优化其培养基配方和培养条件。结果表明,梅奇酵母最大生物量的培养基配方为：2%蔗糖＋2%牛肉蛋白胨＋0.05%磷酸二氢钾＋0.05%硝酸钠;最优培养条件为：培养温度25℃,初始pH 6.0,接种浓度1%;在上述培养条件下进行摇瓶培养,梅奇酵母的最佳培养时间为接种后72 h。     

黄麻链霉菌NF0919菌株发酵提取液HPLC检测分析及稳定性研究

采用HPLC法检测分析了黄麻链霉菌NF0919菌株发酵提取液的主要有效成分,以确定该发酵液的HPLC检测方法,采用菌丝生长速率法对不同处理条件下的发酵提取液进行抑菌活性测定,以确定该发酵提取液的稳定性。结果表明,在采用C18柱,波长305nm,甲醇与水梯度洗脱的条件下,所检测到的发酵提取液物质成分最多;该菌株发酵提取液对热、碱、紫外线的稳定性较差,对酸、光照均较稳定,在冰箱贮藏条件下,该菌株的发酵提取液稳定性较强,具有一定的研究开发价值。