Molecular detection of Fusarium solani f. sp. glycines in soybean roots and soil

A polymerase chain reaction (PCR)-based method was developed to detect DNA of Fusarium solani f. sp. glycines , the cause of soybean sudden death syndrome. Two pairs of primers, Fsg1/Fsg2 designed from the mitochondrial small subunit ribosomal RNA gene, and FsgEF1/FsgEF2 designed from the translation elongation factor 1-α gene, produced PCR products of 438 and 237 bp, respectively. Primer specificity was tested with DNA from 82 F. solani f. sp. glycines , 55 F. solani non-SDS isolates, 43 isolates of 17 soybean fungal pathogens and the oomycete Phytophthora sojae , and soybean. The sensitivity of primer Fsg1/Fsg2 was 10 pg while that of FsgEF1/FsgEF2 was 1 ng when using F. solani f. sp. glycines total genomic DNA or down to 10³ macroconidia g⁻¹ soil. Nested PCR increased the sensitivity of the PCR assay 1000-fold to 10 fg using primers Fsg1/Fsg2, and 1 pg using primers FsgEF1/FsgEF2. F. solani f. sp. glycines DNA was detected in field-grown soybean roots and soil by PCR using either single pairs of primers or the combination of two pairs of primers. The occurrence of F. solani f. sp. glycines was determined using nested PCR for 47 soil samples collected from soybean fields in 20 counties of Illinois in 1999. F. solani f. sp. glycines was detected in soil samples from all five Illinois Agricultural Statistic Districts including 100, 89, 50, 92 and 50% of the samples from East, Central, North-east and West Districts, respectively.     

Aggressiveness of Xanthomonas axonopodis pv. glycines isolates to soybean and hypersensitivity responses by other plants

Xanthomonas axonopodis pv. glycines ( Xag ) causes bacterial pustule disease which can significantly reduce the production of soybean. A collection of 26 isolates of Xag from different soybean-production areas of Thailand was shown to differ with regard to aggressiveness on soybean. They also differed in their ability to induce a hypersensitive response (HR) on four cultivars of tobacco and on other plant species including pepper, tomato, cucumber, pea and sesame. Tomato was most sensitive to HR induction by Xag . Isolate KU-P-34017 caused an HR on all the plant species tested. The minimal concentration of KU-P-34017 needed to induce HR on tobacco was approximately 5 × 10⁸ CFU mL⁻¹. A bacterium–plant interaction period of at least 2·5 h was necessary for HR, and different temperatures, relative humidity and light periods did not affect HR development. Inhibitors of eukaryotic metabolism, including cobalt chloride, lanthanum chloride and sodium orthovanadate (completely), and cycloheximide (partially) blocked the HR on tobacco, indicating the association of an active plant response. In contrast, the HR on tomato was inhibited only by cobalt chloride.     

SCN侵染对不同大豆品种根系氨基酸/低分子肽类分泌物的影响

 利用聚酰胺薄膜层析技术研究了不同抗感SCN的大豆品种根系分泌物中氨基酸/低分子肽类物质。结果表明:大豆根分泌物中含有多种氨基酸类物质及谷胱甘肽等低分子肽类物质;大豆胞囊线虫侵染后, 大豆根的分泌活动增强, 根分泌物中氨基酸/低分子肽类物质增多;苗期大豆根分泌物中氨基酸/低分子肽类物质的种类和含量随苗龄有不同程度的变化, 运用SPSS软件对层析图谱进行聚类和相似性分析, 结果为出苗5和11 d, 各个品种根分泌物层析图谱差异显著, 其中Franklin和辽豆10的图谱相似, 5和11 d时, r分别为0.6683^**和0.7581^**(P=0.01), 且二者均为苗期线虫侵入型品种。因此, 以Franklin或辽豆10根分泌物层析图谱荧光点作参照, 聚酰胺薄膜层析法可检测大豆苗期是否抗线虫侵入。     

黄淮海大豆新品种（系）的抗病性评价

大豆花叶病毒（SMV）、大豆孢囊线虫（SCN）和大豆根腐病（SRR）是危害中国乃至世界大豆生产的3种主要病害。为了评价黄淮海选育的大豆新品种（系）对这3种病害的抗性水平, 采用温网室接种鉴定及田间调查自然发病的方法, 对72份大豆新品种（系）进行了抗病性鉴定。结果表明, ‘中作J8012’、‘蒙01-38’、‘汾豆86’、‘中作X96328’、‘阜08-190’等9个品系对SMV流行株系SC3和SC7表现高抗或抗病, 占参试品种总数的12.5%; ‘周01015-1’、‘远育8号’和‘冀豆17’ 3个品系对SCN 1号生理小种表现中抗; 自然条件下, 抗SRR病情指数在15以下的大豆材料有31份, 占鉴定总数的43.06%; 对SMV和SRR的抗性水平均在中抗及以上的有‘阜08-325’、‘HD0113’、‘太丰6号’等8个品系, 占参试品种数的11. 11%, 而对3种病害的抗性水平均在中抗以上的材料仅有‘冀豆17’1份。本研究的结果可为大豆抗病育种选择亲本和培育多抗性的大豆新品种提供参考。     

Genetics of soybean-Heterodera glycines system

Genetics of resistance to soybean cyst nematode (SCN), Heterodera glycines Ichinohe is very complex. Crosses involving PI 437654, which is resistant to all races of cyst nematodes with other sources of resistance (Peking, PI 88788, and PI 90763) indicated that resistance to race 3 was controlled by four genes, two of which were dominant resistance genes and the other two were recessive resistance genes. For race 5, a four gene model with two recessive and two dominant resistance genes in epistasis has been proposed. For race 14, the results suggested a three gene model with one dominant and two recessive alleles. Several other plant introductions have been isolated which have different genes conditioning resistance. Most of the currently grown soybean varieties derived resistance from Peking and/or PI 88788. Resistance to SCN in these soybean varieties has broken down because of the emergence of several new races and populations of SCN. The use of PI 437654 or Hartwig and other plant introductions with different genes for resistance will broaden genetic diversity and stabilize yield.     

Systemic properties of myclobutanil in soybean plants, affecting control of Asian soybean rust (Phakopsora pachyrhizi)

BACKGROUND: The demethylation inhibitor (DMI) fungicide myclobutanil can be an effective component of spray programmes designed to control the highly destructive plant pathogen Phakopsora pachyrhizi Syd. & P. Syd., causal agent of Asian soybean rust. Myclobutanil is known from previous studies in grapevines to be xylem mobile. This study investigates the mobility profile of myclobutanil in soybean as an important component of its effective field performance. RESULTS: Over a 12 day period under greenhouse conditions, a constant uptake of myclobutanil from leaflet surfaces into the leaflet tissue was observed. Once in the leaflet, myclobutanil was seen to redistribute throughout the tissue, although no movement out of leaflets occurred owing to a lack of phloem mobility. The ability of myclobutanil to redistribute over distance within the soybean plant was revealed when visualizing movement of the compound to foliage above the point of application on the plant stem. An efficacy bioassay demonstrated that the systemic properties of myclobutanil allow control of disease at a point remote from the initial site of compound application. CONCLUSION: It is suggested that the high degree of xylem systemicity displayed by myclobutanil in soybean foliage is a contributory factor towards its commercial effectiveness for control of Asian soybean rust. Copyright © 2008 Society of Chemical Industry     

甘肃省陇东南大豆孢囊线虫的发生和分布

为了解甘肃省陇东南地区大豆孢囊线虫病分布和发生程度,采用Z字形取样法,对甘肃省陇东南地区9个县(区)37个乡镇大豆孢囊线虫病的发生和分布进行调查,并根据形态特征和rDNA-ITS序列比对鉴定线虫种类。共采集土样411份,陇东地区大豆孢囊线虫检出率为87.2%,其中镇原、西峰、正宁、华池和环县的检出率最高,达100%,镇原孢囊发生量最大,平均孢囊数为11.4个/100 g土;陇南地区大豆孢囊线虫检出率为63.7%,成县和徽县分别为64.0%、63.0%,平均孢囊数分别为0.9和1.2个/100 g土。经形态学特征观测和rDNA-ITS序列比对,甘肃省陇东南采集到的孢囊线虫均鉴定为大豆孢囊线虫Heterodera glycines。     

几丁质酶与大豆抗胞囊线虫关系初步研究

 几丁质酶作为病原物和寄主植物相互作用中的一种重要蛋白质,已成为在植物抗病虫害研究中的热点。线虫卵壳及表皮的主要组成成分是几丁质,与真菌病原物一样,植物被线虫侵染时,可产生几丁质酶^[1]。     

大豆种传菜豆荚斑驳病毒的研究进展

近年来随着我国大豆进口量激增,国内检疫机构多次从美国进口大豆中检出大豆种传病毒菜豆荚斑驳病毒(Bean pod mottle virus,BPMV)。该病毒是我国植物检疫对象,我国为非疫区,了解和掌握该病毒的生物学特性、为害及其检测技术等方面研究进展和口岸检疫措施与防治办法非常重要。对此,做了综述。     

侵染大豆的花生斑驳病毒公主岭分离物基因组测序及分析

本研究利用小RNA深度测序法在大豆叶片上检测到1株花生斑驳病毒Peanut mottle virus (PeMoV),根据小RNA深度测序结果和GenBank公布的PeMoV基因组序列设计引物克隆了PeMoV公主岭分离物(PeMoV-Gongzhuling)的基因组序列.测序结果经拼接后获得了PeMoV-Gongzhu...     

控制大豆孢囊线虫生物种农剂的研制及沈阳田间小区防效的初步试验

以“辽豆15”为材料,采用田间小区试验,探讨了自行研制的生物种衣剂对大豆孢囊线虫数量的影响。试验结果表明：2007年在沈阳汪家的试验中,处理4（复配菌株F1024,B482,A4+微量元素组合3+助剂）对大豆根外孢囊的抑制率达65.66%,与对照有显著差异。2008年对处理4进行了精细的试验设计,并在2个不同地点布置试验,结果处理5（复配菌株F1024,B482,A4+元素组合+助剂）在汪家和康平2个试验点的根外孢囊数量及根内线虫数量都与对照差异达到显著水平,2个试验点的根外孢囊抑制率分别为 62.13%和46.45%,根内线虫抑制率分别为62.50%和81.78%。     

野生大豆(Glycine soja)抗斜纹夜蛾资源鉴定

近年来斜纹夜蛾已发展为影响大豆生产的世界性虫害。对大豆抗斜纹夜蛾种质资源进行鉴定是开展抗虫育种的基础。野生大豆是栽培大豆祖先种,遗传多样性远远超过栽培大豆,从野生种质中发掘斜纹夜蛾抗性资源可以拓宽抗虫育种遗传基础。采用室内喂养斜纹夜蛾幼虫的方法,以幼虫重和蛹重为指标,鉴定了35份野生大豆和20份栽培大豆对斜纹夜蛾的抗性。结果显示:不同种质饲喂下,幼虫重、蛹重和幼虫历期在种质间差异极显著,遗传变异幅度较大,幼虫重和蛹重极显著相关。采用标准品种分级法对抗性鉴定结果进行划分,从55份供试资源中筛选出6份高抗种质,均来自野生大豆;5份高感材料,1份来自野生大豆。本研究为大豆抗斜纹夜蛾育种提供了原始材料,同时有助于大豆抗虫遗传研究与新基因发现。     

河北东部沿海地区野生大豆病毒病抗性与几种酶活性的关系

 对来源于河北东部沿海地区的129份野生大豆进行抗大豆花叶病毒病鉴定。结果表明,2.3%的野生大豆抗大豆花叶病毒病,14.7%的野生大豆表现为中抗,26.4%的野生大豆表现为中间反应类型。选取11份不同抗性水平野生大豆进行生化指标的比较,相关分析表明,POD和SOD酶活性与野生大豆对病毒病的抗性无明显的相关性,而PPO和PAL活性与野生大豆对病毒病的抗性呈显著正相关,可利用PPO和PAL活性作为野生大豆病毒病抗性鉴定的参考指标。     

不同大豆品种与SCN 3号生理小种互作效应研究

 在田间研究了不同大豆品种对大豆胞囊线虫(soybean cyst nematode,SCN)的发育及繁殖的影响不同。结果表明,辽K89102为抗侵入型品种,Peking、PI90763、应县小黑豆、磨石豆和Franklin等的根内线虫从J2向J3或J3向J4发育过程中受到抑制,这些品种均有不同程度的抗线虫发育特性;不同品种对其根内SCN的雌雄分化有较大影响,感病品种根内SCN雌雄比远大于抗病品种,辽豆10根内线虫雌雄比例最高,为11.5:1.0,Peking根内线虫雌雄比例最低,为0.1:1.0;不同品种根围SCN最终群体量有较大差异,辽豆10根围土壤中胞囊量增加了331.5%,Peking和磨石豆的增幅最小,为16.7%。SCN侵染后,不同品种产生的组织病理学反应不同,抗病品种产生明显的组织病理学反应,表现在品种Peking和PI437654的根内线虫虫体附近根组织细胞有坏死现象,而感病品种辽豆10和开育10则没有坏死现象。     

Natural hybridization in wild soybean (Glycine max ssp. soja) by pollen flow from cultivated soybean (Glycine max ssp. max) in a designed population

The frequency of hybridization through pollen flow from the cultivated soybean to the wild soybean was evaluated for the purpose of assessment of the ecological risk of genetically modified crops. The flowering habits of three soybean cultivars and one wild soybean accession were monitored on an experimental farm. A cultivar and a wild accession, both of which flowered at a similar period, were then planted alternately in 5 12 arrays with 50 cm spacing on the farm. The seedlings of progeny seeds gathered from individual plants of the wild accession were used for an isozyme analysis to identify whether they were hybrid or not. In 23 plants of the wild accession, four plants produced hybrids (the incidence of hybridization = 17.4%). There was no directionality in hybridization. The hybridization rate per maternal plant varied from 0 to 5.89% with a mean of 0.73% for all maternal plants. The results indicate that natural hybrids are easily produced in a certain frequency by pollen flow from the cultivated soybean to the wild soybean under their simultaneous flowering with adequate pollinators.     

大豆孢囊线虫大豆和烟草群体寄生性比较分析

通过盆栽试验,测定大豆孢囊线虫(Heterodera glycines,soybean cyst nematode,SCN)大豆群体(SCNS)和烟草群体(SCN_T)对5个大豆品种(SCN生理小种鉴别寄主)和9个烟草栽培品种的寄生性。结果发现,SCNS在5个大豆品种上的平均繁殖系数(Rf=P_f/P_i)为0.60(0.14~1.90),在感病对照品种‘Lee’上平均Rf高达1.90;SCN_T在5个大豆品种上的平均Rf为0.18(0.06~0.44),在感病对照品种‘Lee’上Rf为0.44。SCNS对9个烟草品种几乎无寄生性,平均Rf为0.06(0.00~0.10);SCN_T则能寄生9个烟草品种,平均Rf为1.26(0.45~1.95)。接种35d后,在不同大豆品种根内SCNS和SCN_T的幼虫数量均极少,侵染率基本相同;在不同烟草品种根内SCNS的幼虫数量均为0,而SCN_T的幼虫数量平均为26.5(14.6~57.0)。研究表明,供试SCNS属于14号生理小种,但供试SCN_T与之寄生性差异大,属于新的SCN致病类型。     

Interference and economic threshold of horse purslane (Trianthema portulacastrum) in soybean cultivation in northern India

Soybean is the most important oilseed crop that is grown in India. Horse purslane (Trianthema portulacastrum L.) infests soybean heavily, causing enormous yield losses and threatening the sustainability of the soybean production system. Information on the interference and economic threshold of horse purslane will be useful for the effective management of horse purslane in soybean. This will lead to the rationalization of herbicide use and the reduction of herbicide input into the environment. It was observed in this study that “a composite stand of weeds including horse purslane”, and 200 horse purslane plants per m² were equally competitive to soybean. These two treatments resulted in a higher dry weight, growth rate, and uptake of N, P, and K by the weeds and/or horse purslane, compared to the other treatments. They caused more reductions in soybean growth (dry weight, height, crop growth rate, net assimilation rate, and leaf area index) and resulted in a more significant yield reduction than did the other treatments. The weed density–crop yield and the relative leaf area–crop yield models were found to be equally effective in simulating soybean yield losses in relation to a wide range of horse purslane densities and the regression equations were a good fit. The quadratic equations revealed that a density of approximately six, five, and four horse purslane plants per m² would be the economic threshold levels of horse purslane in soybean cultivation, when considering the 70, 80, and 90% horse purslane control efficiencies, respectively, of the herbicide, lactofen.