菌核生枝顶孢霉次生代谢物对桃褐斑致病菌的抑制效果

菌核生枝顶孢霉(Acremoniumsclerotigenum)作为枝顶孢属真菌的优势种,其次生代谢产物多样。为了明确其对植物病害致病菌的抑制效果,以桃褐斑致病菌(Alternariaalternata)为靶标菌,采用菌丝生长速率法和孢子萌发法测定6种发酵液的抑菌活性。结果表明:PD培养基发酵液提取物对桃褐斑致病菌的抑制效果最好,对菌丝生长和孢子萌发的EC50分别为53.6734mg/L和808.1584mg/L;培养5d的PD培养基发酵液的抑菌效果最好,对菌丝生长和孢子萌发的EC50分别为1.4458mg/L和309.6318mg/L;菌核生枝顶孢霉发酵液对桃褐斑致病菌菌丝生长的抑制效果优于对孢子萌发效果。该研究结果为将其开发成生物源农药奠定了理论基础。     

设施果树栽培应注意的几个问题

日光温室和塑料大棚等设施果树栽培是高效农业的范畴,这种生产方式投资大,收益好,风险性也高.为了尽可能地避免造成损失,在进行设施果树栽培时应慎重对待以下问题:     

一株新的引起玉米细菌性茎腐病病原细菌的分离鉴定

In 2019, the disease was observed in the maize growing areas of Dehong County, Yunnan Province, China. On the basis of signs and symptoms, the disease was characterized as a bacterial infection. Identification of the pathogen were based on morphological characteristics, biology and physiological and biochemical assay, 16S rDNA and specific rpoD and gapA gene sequence analysis. The results show that the pathogen is similar to short rod in shape under a transmission electron microscope, the both ends are obtuse and have 1-3 terminal flagella. In King’s B medium, it produced milky white, round, smooth surface and transparent edge colonies and can utilize the 58 kinds of carbon sources. The LOPAT test result is “+++-+”. The construction of evolutionary trees was based on the 16S rDNA、rpoD and gapA gene sequencing, which indicated the closest genetic relationship with Pseudomonas extremorientalis and which was finally identified as P. extremorientalis. To our acknow-ledgment, this is the first report on the bacterial stalk rot disease of maize caused by phytopathogenic bacteria P. extremorientalis.     

不同烤烟套作模式对烤烟根际土壤细菌群落特征及烤烟产质量的影响

目的研究云南玉米大豆间作模式对玉米根际微生物群落特征、玉米产量及病害的影响,为玉米大豆间作模式的田间应用提供科学依据。方法采用单因素随机区组试验,通过设置玉米大豆间作和玉米单作处理,利用Illumina Miseq高通量测序技术分析间作玉米根际土壤微生物群落结构及其多样性,并进行玉米产量、病害发生与根际微生物变化之间的相关性分析。结果间作玉米产量显著高于单作玉米产量(P<0.05);与单作相比,间作后玉米锈病、玉米灰斑病、玉米小斑病和玉米大斑病的病情指数显著降低;间作可提高玉米根际土壤微生物多样性指数(真菌和细菌Observed_species指数、Chao1指数和Shannon指数)。差异OTUs分析结果显示：细菌中276个OTUs在玉米大豆间作中显著富集,251个OTUs在玉米单作中显著富集,芽单孢菌属(Gemmatimonas)和溶杆菌属(Lysobacter)等菌属的数量在玉米大豆间作中显著升高,伯克氏菌属(Burkholderia)和鞘脂菌属(Sphingobium)等菌属的数量显著降低;真菌中146个OTUs在玉米大豆间作中显著富集,141个OTUs在玉米单作中显著富集,被孢霉属(Mortierella)和壶菌属(Spizellomyces)等菌属丰度在玉米大豆间作中显著升高,而镰刀菌属(Fusarium)和梭杆菌属(Monographella)等菌属丰度显著降低。功能注释结果显示：玉米大豆间作能使玉米根际土壤中具有促进氮元素转化、有机物分解和改善土壤结构功能的有益微生物的丰度增加,而注释到潜在致病菌有害微生物丰度降低。结论玉米大豆间作改变了玉米根际微生物的群落结构,提高了细菌和真菌的多样性,使根际土中有益微生物数量增加,同时潜在致病菌等有害微生物数量降低,提高了玉米的抗病能力,增加了产量。     

抗生素溶杆菌13-6对玉米小斑病的生防作用机制初步研究

玉米小斑病是玉米生产中的重要病害之一,本研究利用传统植物病理学和荧光定量PCR方法,研究抗生素溶杆菌对玉米小斑病菌(Bipolaris maydis)的生防效果和作用机制,为玉米小斑病的生物防控提供理论依据.结果显示,抗生素溶杆菌13-6对玉米小斑病菌丝生长和孢子萌发具有显著抑制作用,造成菌丝顶端生长受阻、表面粗糙,部...