Impact of long-term chemical fertilizer and organic amendment to Fusarium root rot of soybean

Soil suppressiveness to Fusarium root rot of soybean had been observed in a black soil field after a long-term fertilization with nitrogen(N)and phosphorus(P)fertilizer combined with pig manure as organic amendment(NPM),rather than that with only nitrogen and phosphorus fertilizer(NP)or no fertilizer(NF).To determine the microbial role on this suppressiveness,fungal and bacterial community characteristics in NPM,NP and NF treatments were investigated by q PCR and DGGE.Compared with the similar bacterial community characteristics among 3 treatments,fungal community,especially Fusarium population size and community composition in NPM treatment were different with those of NP and NF groups.Based on the isolation and pathogenicity test,pathogenic F.oxysporum,F.graminearum,F.verticillioide and F.lateritium absolutely dominated Fusarium community in NF and NP groups.Nonpathogenic F.avenaceum,F.equiseti,F.culmorum,F.redolens,F.solani and F.tricinctum dominated Fusarium community in NPM group.Isolation rate of pathogenic Fusarium in NPM reduced from 100%to 38%in NF.These results suggested that the dominance of soil non-pathogenic Fusarium population induced by organic amendment might play an important role on suppressing Fusarium root rot in the tested field.

Resistance Evaluation of Soybean Germplasm from Huanghuai Region to Phytophthora Root Rot

The aim of the study was to establish a set of differential strains and to identify soybean resistant genes to Phytophthora root rot and then to apply those strains for analysis of the resistant genes Rps1a,Rps1c,and Rps1k that soybean cultivars or lines may carry.Virulence formula of 125 Phytophthora sojae isolates were determined using the hypocotyls inoculation technique,the strains,which includ 6 isolates with different virulence formulas,were applied to identify the resistance of 55 soybean cultivars or lines and resistant genes were analyzed using the gene postulating procedure.Eighteen reaction types occurred in 55 cultivars or lines and results of gene postulation indicated that 2 cultivars or lines probably carried gene Rps1c and no cultivar may carry genes Rps1a or Rps1k.A few of soybean cultivars or lines from Huanghuai Region carry Rps genes Rps1a,Rps1c and Rps1k and tend to infect by P.sojae,so resistant cultivars or lines need to be bred and popularized actively.

Relationships between Microsclerotia Content and Hyperspectral Reflectance Data in Soybean Tissue Infected by Macrophomina phaseolina

Alternative methods are needed to assess the severity of charcoal rot disease [Macrophomina phaseolina (Tassi) Goid] in soybean [Glycine max (L.)] plant tissue. The objective of this study was to define the relationship between light reflectance properties and microsclerotia content of soybean stem and root tissue. Understanding that relationship could lead to using spectral reflectance data as a tool to assess the severity of charcoal rot disease in soybean plants, thus reducing human bias associated with qualitative analysis of soybean plant tissue and cost and time issues connected with quantitative analysis. Hyperspectral reflectance measurements (400-2490 nm) were obtained with a non-imaging spectroradiometer of non-diseased and charcoal rot diseased ground stem and root tissue samples of six soybean genotypes (“Clark”, “LD00-3309”, “LG03- 4561-14”, “LG03-4561-19”, “Saline”, and “Y227-1”). Relationships between the reflectance measurements and tissue microsclerotia content were evaluated with Spearman correlation (rs) analysis (p < 0.05). Moderate (rs = ±0.40 to ±0.59), strong (rs = ±0.60 to ±0.79), and very strong (rs = ±0.80 to ±1.00) negative and positive statistically significant (p < 0.05) monotonic relationships were observed between tissue spectral reflectance values and tissue microsclerotia content. Near-infrared and shortwave-infrared wavelengths had the best relationships with microsclerotia content in the ground tissue samples, with consistent results obtained with near-infrared wavelengths in that decreases in near-infrared spectral reflectance values were associated with increases in microsclerotia content in the stem and root tissue of the soybean plants. The findings of this study provided evidence that relationships exist between tissue spectral reflectance and tissue microsclerotia content of soybean plants, supporting spectral reflectance data as a means for assessing variation of microsclerotia content in soybean plants. Future research should focus on the modelling capabilities of the selected wavelengths and on the feasibility of using these wavelengths in machine learning algorithms to differentiate non-diseased from charcoal rot diseased tissue.

Conidia of one Fusarium solani isolate from a soybean-production field enable to be virulent to soybean and make soybean seedlings wilted

Fusarium is usually thought to cause soybean root rot, which results in a large quantity of annual yield loss in soybean production, by its secretions including Fusarium toxins and cell wall degrading enzymes, but not by the conidia themselves that do not underlie any virulence so far. Here we report that the conidia of one Fusarium solani isolate are able to be virulent to soybean and make soybean seedlings wilted alone. We isolated them from the wilted plants in a soybean-production field and molecularly identified 17 Fusarium isolates through phylogenetic analysis. Of them, except for one isolate that showed diversity of virulence to different soybeans （virulent to one soybean whereas avirulent to another soybean）, the others were all virulent to the two tested soybeans： both conidia cultures and secretions could make soybean seedlings wilted at 5 days post infection, and their virulence had dosage effects that only conidia cultures of at least 5×10^6 conidia mL-1 could show virulence to soybean; however, the sole conidia of the F. solani isolate #4 also exhibited virulence to soybean and could make soybean seedlings wilted. Finally, we developed the specific cleaved amplified polymorphic sequences （CAPS） markers to easily differentiate Fusarium isolates. The isolate #4 in this work will likely be used to investigate the new mechanism of virulence of Fusarium to soybean.

Resistance identification of bivalent fungi-resistant genes transformed soybean to Phytophthora sojae

Soybean is one of the most important sources of edible oil and proteins in the world. However, it suffers from many kinds of fungal diseases which is a major limiting factor in soybean production. The fungal disease can be effectively controlled by breeding plant cultivars with genetic transformation. In this study, the resistance to Phytophthora sojae of five bivalent transgenic soybean lines was identified using the hypocotyls inoculation technique. The lines were the T2 of the transgenic soybean which were transformed with kidney bean chitinase gene and barley ribosome inactivating protein gene, and were positive by Southern Blot analysis. The resistance difference was studied through comparing the death percentage of transgenic soybean with the control. The results showed that four lines were more resistant to P sojae, whereas other one had no significant difference in comparison with the control. These transgenic soybean lines with enhanced resistance to P sojae will be useful in soybean resistance breeding.

大豆镰刀菌根腐病拮抗菌的筛选及生防效果

【目的】镰刀菌根腐病是世界范围内大豆生产上最具破坏性的土传病害之一,为获得对禾谷镰刀菌Fusarium graminearum具有较好拮抗效果的生防菌株。【方法】从健康大豆根际土壤分离细菌,平板对峙法筛选拮抗菌株,通过形态观察、生理生化特性、胞外酶活性及促生特性对菌株进行鉴定分析,采用盆栽试验进一步测定菌株生防及促生效果。【结果】筛选出的4株芽孢杆菌和1株假单胞杆菌对F.graminearum的抑菌率均达到60%以上,对F.oxysporum,F.solani,F.longifundum以及F.equiseti也均有一定的抑制作用,其发酵液及挥发代谢物均会影响F.graminearum的生长。5株拮抗菌具有产蛋白酶、纤维素酶以及葡聚糖酶的活性,解磷、解钾、固氮以及产铁载体的能力。综合以上测试结果,菌株20-8具有较强的抑菌及大豆促生效果。根据形态特征及16S rRNA序列分析,将菌株20-8鉴定为暹罗芽孢杆菌(Bacillus siamensis)。该菌株的发酵上清液可以破坏F.graminearum菌丝体结构,无细胞发酵上清液可以显著抑制孢子萌发。室内盆栽防效测定结果表明,20-8的稀释发酵液对F.graminearum引起大豆根腐病的防效可达46.08%,并且促进大豆植株生长。【结论】筛选鉴定的暹罗芽孢杆菌20-8具有解磷、解钾、固氮以及产铁载体及多种胞外酶功能,其稀释发酵液具有较强的抗真菌活性及大豆促生能力,菌株20-8可以用于防治F.graminearum引起的大豆根腐病。

镰孢菌引发的大豆根腐病及其生物防治研究进展

大豆是我国主要粮食和经济作物之一,但其产量和品质极易受病害影响。大豆根腐病是世界范围内较为常见的大豆病害类型。镰孢菌(Fusarium)是大豆根腐病的主要致病菌之一。本文综述了由镰孢菌引发的大豆根腐病的发生条件、发病症状及病害影响,并分析了镰孢菌引发大豆根腐病的致病性与发病机理。通过尖孢镰孢菌(F.oxysporum)和禾谷镰孢菌(F.graminearum)的致病性研究发现,镰孢菌属菌株可以通过破坏宿主植物免疫应答系统或分泌真菌毒素破坏植物细胞等方式引发大豆根腐病。同时不同病原菌之间还存在协同互作机制,可通过分泌促侵染关键物质协同逃脱宿主植物防御。本文总结了镰孢菌引发的大豆根腐病的生物防治研究进展。生物防治手段集合多个作用靶点于一体,通过转录组学技术能够揭示生物防治的作用机理,而生防微生物固有的活体属性所带来的应用局限性则可通过与农业田间管理、化学防治相结合等方式加以攻破。本文还对关于大豆根腐病乃至各类农业生产病害的生物防治未来研究方向进行了展望。

大豆根腐病致病病原菌及其抗性研究进展

文章综述大豆根腐病病原菌鉴定与分布、抗病性鉴定与抗病基因挖掘研究现状,从栽培措施、化学防治、定向育种、生物防治方面总结根腐病防治方法,展望未来研究方向,旨在为提高大豆产量提供科学依据。

浅析黑龙江省大豆根腐病研究现状

大豆根腐病为大豆主要病害之一,具有发病范围广、卵孢子存活时间长、危害重等特点,严重制约黑龙江省大豆产业发展。为提高黑龙江省大豆根腐病防控技术水平,文章综述黑龙江省大豆根腐病致病菌种类及分布、发病症状及特点、抗病品种鉴定及防治措施,以期为黑龙江省大豆根腐病防治及研究提供理论依据,助力黑龙江省大豆产业振兴。

黑龙江省北部地区大豆种质对疫霉根腐病抗性评价

为了明确黑龙江省北部地区大豆种质资源对大豆疫霉根腐病的抗耐情况,采用下胚轴创伤接种法,对适宜该地区种植的113份大豆育成品种或育种材料的大豆疫霉根腐病抗性开展鉴定。结果显示:共鉴定出7份抗病种质,占鉴定总数的6.19%;5份中间类型种质,占鉴定总数的4.42%。其中,从第三积温带种质中鉴定出1份抗病种质,中间类型种质1份;从第四积温带种质中鉴定出抗性种质3份,中间类型种质2份;从第五积温带种质中鉴定出抗性种质1份,中间类型种质2份;从第六积温带种质中鉴定出抗性种质2份,未见中间类型种质。结果表明在不同积温带参试材料中均存在抗性种质。该研究结果为黑龙江省北部地区培育和利用抗疫霉根腐病大豆种质提供了参考。

不同类型农药对大豆根腐病的田间防治效果

为筛选有效防控大豆根腐病的种衣剂,开展杀菌剂复配使用和微生物农药拌种对大豆根腐病田间防效试验。结果表明,40%溴酰·噻虫嗪FS+11%氟环·咯·精甲FS和62.5 g/L精甲·咯菌腈FSC拌种对大豆根腐病有较好的防治效果,大豆出苗后15 d防效在70%以上,微生物农药1000亿芽孢/g枯草芽孢杆菌WP和10亿芽孢/g多粘类芽孢杆菌WP也可有效防控大豆根腐病,防效为50.86%~60.71%,虽然防效低于杀菌剂复配使用,但其对环境、人畜安全,具有广阔的应用前景。因此,在未来大豆根腐病防治中,应进一步优化复配药剂组合,同时充分发挥微生物农药的作用。

大豆两种病害抗性机制及抗病育种研究进展

大豆花叶病毒病和大豆疫霉根腐病作为大豆减产的主要因素,制约着大豆产量的提升和性状的稳定,长期以来受到育种学家的重视。目前没有有效的方法防治这两种病害,通过发掘抗病基因,利用转基因技术培育抗病品种,是最有效安全的途径。本文从分子水平综述了这两种病害的抗病基因、抗病分子机制,并探讨了大豆抗病性改良的潜在途径,以期为大豆抗病育种研究提供思路。

6株生防细菌对大豆根腐病防治效果初步评价

从大豆根际分离出的1500多株细菌中筛选出6株生防细菌,其在离体的条件下对大豆根腐病病原菌尖孢镰刀菌(Fusarium oxysporum )有很好的抑制作用,其中菌株18BRR2-2、18BRR9-1和3BRR16-2在离体的条件下也对茄腐镰刀菌(F. solani)、半裸镰刀菌(F. semitectum) 和立枯丝核菌(Rhizoctonia solani)有抑制作用,并且这6株生防细菌的发酵液可以抑制尖孢镰刀菌(F. oxysporum )的生长。通过温室盆栽和大田试验表明,这些生防菌对大豆根腐病有很好的防治效果,其中菌株18BRR2-2盆栽和大田的防效均最高,分别达到了45.9%和65.00%。而且这些生防菌也表现出对大豆明显的促生作用。认为18BRR2-2 号菌株有开发为防治大豆根腐病生防制剂的潜力。

新疆阿勒泰地区大豆镰刀菌根腐病病原鉴定及致病性测定

通过对2007和2008连续两年自新疆阿勒泰地区采集分离到的大量大豆镰刀菌根腐病分离物进行的种的鉴定,结果表明分离所得253个镰刀菌属菌株分属于5个种和1个变种,分别为尖孢镰刀菌、茄腐镰刀菌、禾谷镰刀菌、茄腐镰刀菌蓝色变种、燕麦镰刀菌和节状镰刀菌。各个种或变种所占的菌株比例分别为46.6%、24.1%、11.8%、9.8%、7.5%和0.8%。以黑河5号大豆品种为接种材料进行的致病性测定结果显示除节状镰刀菌无致病性外,其余4个种和1个变种对大豆有不同程度的致病性,其中尖孢镰刀菌为大豆镰刀菌根腐病病原菌中出现频率最大且致病性最强的优势致病种,茄腐镰刀菌次之。

福建省大豆根腐病病原菌的鉴定

为明确福建省大豆根腐病病原菌的种类及组成,于2007～2009年从漳州、厦门、龙岩等地大豆产区采集根腐病标样216份,从中分离到307株丝状病原真菌。根据其培养性状、形态学特征、代表性菌株的致病性测定及rDNA-ITS序列分析,将这些病原菌分为5种,分别为尖孢镰刀菌(Fusarium oxysporum,112株)、茄腐镰刀菌(Fusarium solani,74株)、大豆疫霉菌(Phytophthora sojae,79株)、立枯丝核菌(Rhizoctoniasolani,24株)和瓜果腐霉菌(Pythium aphanidermatum,18株)。致病性测定结果表明,5种病原菌的致病力存在明显差异,其中大豆疫霉菌、尖孢镰刀菌和茄腐镰刀菌的致病性较强,发病率分别为100%、97.8%和95.6%,立枯丝核菌、瓜果腐霉菌则相对较弱。

复配生防菌株防治大豆根腐病的研究

大豆根腐病(Soybean root rot)是由多种病原真菌复合侵染所致的土传病害,其分布广、危害重,利用单一生防菌株防治困难。针对该问题将实验室筛选出的多个木霉菌生防菌株FMM35、FMM9、FMM5,毛壳菌CHZ1和生防细菌B7进行复配研究,通过测定生防菌的生长速度、产孢量、孢子萌发率及体外拮抗能力,探索复配可能性,并将适宜复配的生防菌组合进行盆栽防效试验。结果表明:不同生防菌之间生长速度、产孢量、孢子萌发率存在差异,综合分析其中组合C1(FMM9和FMM35)复配效果好,避免生防菌间拮抗作用,对大豆根腐病防治效果明显,并对大豆有促生作用,具有复配潜力可进一步研究。

新疆大豆根腐病病原及防治技术初报

通过对大豆根腐病菌的分离、纯化培养和接菌试验,初步确定新疆大豆根腐病是由多种病原菌复合侵染所至,单一菌种的致病力小于复合菌种。药剂处理种子经室内、田间试验,多菌灵和福美双处理种子出苗情况良好,病情指数降低幅度明显,防病效果显著。

大豆根腐病生防细菌优势菌株的筛选、鉴定及生防效果验证

根腐病是影响大豆产量的主要病害之一,镰刀菌(Fusarium sp.)是引起我国大豆根腐病的主要病原菌。以致病尖孢镰刀菌为研究对象,通过平板对峙法从实验室保存的237株芽孢杆菌筛选到一株对该尖孢镰刀菌具有明显抑菌活性的芽孢杆菌8-32。对芽孢杆菌8-32经菌落、菌体形态,16S rRNA基因序列及生理生化性质鉴定,该菌株为枯草芽孢杆菌(Bacillus subtilis)。温室盆栽结果表明:该生防菌对大豆根腐病具有很好的防治效果,其病情指数减少32.08%。

大豆根腐病菌拮抗细菌筛选及抗生作用

从大豆根际土壤中分离纯化得到 388个细菌菌株 ,从中筛选对大豆根腐病病原尖孢镰刀菌 (Fusariumoxysporum )、茄腐镰刀菌 (Fusariumsolani)和立枯丝核菌 (Rhizoctoniasolani )有拮抗作用的菌株 ,采用无菌室内点接法初筛 ,抑菌带大于 2 0mm以上的有 12株 ,通过盆栽防效试验 ,进一步证明 12个菌株中有 6个菌株盆栽防治尖孢镰刀菌和立枯丝核菌达到 4 6 .0 % - 78.5 %。菌株与病原真菌共培养结果显示 ,菌株B2、B5 7、B85和B6 9使尖孢镰刀菌菌丝干重分别减少 5 1.2 7%、4 0 .78%、38.87%和 34.5 8% ;菌株B5 7使茄腐镰刀菌菌丝干重减少 71.4 8%。菌株分泌物对病原真菌的拮抗作用研究结果表明 ,B5 7的分泌物对尖孢镰刀菌抑制率最高 ,3d为 82 .1% ,6d为 90 .6 % ;其次是B16 ,3d为 5 8.8% ,6d为 5 1.1%。

中国大豆疫霉根腐病和大豆种质抗病性研究

大豆疫霉根腐病在中国的发生区域逐渐扩大 ,局部地区发生严重。大豆疫霉菌 1号生理小种是黑龙江省的优势小种 ,同时也存在其它已知生理小种和新生理小种。不同大豆生态区之间大豆疫霉菌生理小种差异显著。在总体上 ,中国大豆种质的抗病性不强 ,长江流域大豆中抗病种质比率最高 ,其次为黄淮海流域种质 ,而东北地区抗病种质较少。按省归类 ,大豆种质抗性由强至弱依次为河南、江苏、湖北、山西、河北、辽宁、吉林、黑龙江、山东。吉林和黑龙江选育推广品种中 ,感病品种分别高达80 %和 73% ;在 4 62份大豆品系中 ,也表现出南方材料抗病性高于北方材料的趋势 ;地方品种中感病类型也高达 60 %以上。