Prevalence of Seed-Borne Fungi Associated with Seeds of Some Selected Flowers

The prevalence of fungi associated with seeds of some selected local flowers namely cosmos, marigold, calendula, and periwinkle collected from three different locations (Arboriculture Garden, Ramna Park Garden, and Horticulture Garden) in Dhaka district and four hybrid flower seeds (African marigold, cockscomb, petunia, and Portulaca) collected from Momin Beej Ghar, Dhaka district were recorded. The results showed that the highest percent germination (91.38%) of cosmos was obtained from Horticulture garden’s seed, marigold (95.25%) obtained from Arboriculture garden’s seed, and calendula (65.88%) periwinkle (79.38%) obtained from Ramna park garden’s seeds. But in the case of hybrid seeds, African marigold showed the highest percent seed germination (98.25%). The Horticulture garden’s seed was better than the others considering the incidence of fungi in all local flower seeds tested. But periwinkle was the lowest affected seed (12.58%, 12.20%, 8.07% incidence) and marigold was the highest affected seed (40.31%, 35.33%, 31.33% incidence) collected from Arboriculture Garden, Ramna Park, and Horticulture Garden, respectively. But in hybrid flower seeds, the lowest fungal infection (3.14%) was recorded in Portulaca and petunia seeds whereas the highest (6.20%) was in African marigold seeds.

Post-Harvest Fungi Associated with Cowpea (Vigna unguiculata L. Walp.) Seeds Produced in Burkina Faso

Cowpea is a very popular foodstuff among people in sub-Saharan Africa. In Burkina Faso, it is the main food legume, especially in rural areas. Its production is facing difficulties including post-harvest losses caused by fungi. Therefore, the objective of this study was to isolate and identify fungal strains associated with cowpea seeds produced in Burkina Faso. Thus, a total of 108 seed samples were collected in the three agro-ecological zones of Burkina Faso. The sanitary analysis of the seeds was carried out using the direct contact method. The isolation and purification of the isolates were performed on Potato Dextrose Agar medium while their identification was done through macroscopic and microscopic phenotypical characterization using different culture media (Potato Dextrose Agar (PDA), Malt Extract Agar (MEA) and Czapeck Dox Agar (CZA)) and different identification keys. A total of 10 fungal species were isolated, with predominance of Aspergillus flavus, Aspegillus niger, Macrophomina phaseolina, Fusarium oxysporium and Rhizopus sp. whose infection rates were 70.8% to 100% of seed samples. In addition to being present in all three zones, the infection rates of Aspergillus flavus (56.55%), Aspergillus niger (20.35%) and Rhizopus (32.80%) were higher in the Sahelian zone. In the Sudano-Sahelian zone, Macrophomina (50.66%) and Fusarium (18.88%) presented the highest infection rates, while Penicillium sp. showed the highest infection rate (2.84%) in the Sudanian zone. This finding demonstrated the necessity to improve post-harvest and conservation techniques of cowpea to limit crop losses and preserve the sanitary quality of this important foodstuff.

基于环介导等温扩增技术检测黄淮地区大豆主栽品种种子携带的病原菌

[目的]通过对黄淮地区大豆种子带菌的快速检测,了解该地区大豆种子携带病原菌的情况。[方法]采用环介导等温扩增技术(loop-mediated isothermal amplification,LAMP)检测黄淮地区29个大豆主栽品种种子上平头炭疽菌、胶孢炭疽菌、尖镰孢菌、木贼镰孢菌、层出镰孢菌、黄色镰孢菌、禾谷镰孢菌、茄腐镰孢菌、大豆拟茎点种腐病菌、立枯丝核菌、大豆炭腐病菌、冬青丽赤壳菌、大豆疫霉病菌等大豆主要病原菌的携带情况。[结果]供试的29个品种中有20个品种的种子样本检出携带上述病原菌,分别携带所检测的13种病原菌中的7种,检出率由高到低依次为平头炭疽菌、大豆拟茎点种腐病菌、木贼镰孢菌、黄色镰孢菌、尖镰孢菌、胶孢炭疽菌和层出镰孢菌,但不同大豆品种种子携带病原菌的种类及数量有较大差异,其中品种‘漯39001’检出的病原菌多达6种。[结论]本研究为大豆种子带菌检测提供了新的方法,并揭示了黄淮地区大豆种子携带病原菌的状况,在生产上有较大的应用价值。

143例老年人肺部感染临床分析

目的探讨老年肺部感染常见相关性疾病和病原菌分布情况。方法对143份老年肺部感染患者的住院病历进行详尽分析。结果绝大多数病例伴有严重基础性疾病,并过多地应用抗菌素。该资料分析显示:对143例患者的痰液细菌培养分离出151株菌株,其中革兰阳性球菌49株(32.5%),革兰阴性杆菌79株(52.3%),厌氧菌4株(2.6%),真菌19株(12.6%)。结论应加强对原有基础性疾病的积极治疗与控制,尽量减少老年肺部感染发生率。根据细菌培养结果,合理指导临床用药,减少细菌耐药性和不良反应的发生。

一品红根腐性病害及防治技术研究

室内病原分离、纯化及鉴定结果表明,一品红根腐性病害致病菌主要包括8种。其中立枯丝核菌(Rhizocto niasolaniKukn)分离比率占51.2%,寄生疫霉和烟草疫霉、腐霉菌次之。多数致病菌主要通过栽培基质进行传播侵染,因此进行基质消毒为重要的防病手段。利用"必速灭"颗粒剂进行拌土消毒灭菌效果可达70.5%。不同药剂对一品红根腐病不同病原菌菌丝生长抑制效果差异较大;通过灌根与喷雾结合防治的手段,利用恶霉灵等多种有效药剂单独或混合用药,可起到诸病兼治的作用。

对虾发光病病原菌的致病性及病理学观察

本文报道了对虾发光病病原菌的致病性、发病症状和病理变化。结果表明:哈维氏弧菌对虾类有极强的致病性,并引起组织和器官不同程度的病变。病理变化表现为:肌纤维颗粒变性,纵裂,坏死:肝胰腺空泡变性,坏死;淋巴器官坏死等。注射感染的发病虾,肝胰腺出现血细胞浸润,说明对虾对细菌感染有一定的防御能力。

健康白鲢鱼体的病原菌

从白鲢鱼体分离到一批溶血毒素产生菌，对这批菌的工病性和毒力相关因子作了检测，并对其中的几株典型菌株作了鉴定。部分溶血毒素产生菌对全体致病，鉴定表明其中两株菌属于嗜水气羊胞菌．实验结果说明健康白鲢鱼作微生物群落中存在致病性嗜水气单胞菌，但致病性与是否吸收刚果红、吸收铁盐等没有必然联系。

A LAMP-assay-based specific microbiota analysis reveals community dynamics and potential interactions of 13 major soybean root pathogens

Soybean root diseases are associated with numerous fungal and oomycete pathogens;however,the community dynamics and interactions of these pathogens are largely unknown.We performed 13 loop-mediated isothermal amplification(LAMP)assays that targeted specific soybean root pathogens,and traditional isolation assays.A total of 159 samples were collected from three locations in the Huang-Huai-Hai region of China at three soybean growth stages(30,60,and 90 days after planting)in 2016.In LAMP results,we found that pathogen communities differed slightly among locations,but changed dramatically between soybean growth stages.Phytophthora sojae,Rhizoctonia solani,and Fusarium oxysporum were most frequently detected at the early stage,whereas Phomopsis longicolla,Fusarium equiseti,and Fusarium virguliforme were most common in the later stages.Most samples(86%)contained two to six pathogen species.Interestingly,the less detectable species tended to exist in the samples containing more detected species,and some pathogens preferentially co-occurred in diseased tissue,including P.sojae–R.solani–F.oxysporum and F.virguliforme–Calonectria ilicicola,implying potential interactions during infection.The LAMP detection results were confirmed by traditional isolation methods.The isolated strains exhibited different virulence to soybean,further implying a beneficial interaction among some pathogens.

Control of seed born mycobiota associated with Glycine max L.Merr.seeds by a combination of traditional medicinal plants extracts

Seeds from soybean collected from different commercial markets were surveyed for seed-borne fungi.Ninetyeight fungal colonies were isolated all over three monthly isolations constituting twenty-two fungal species.The isolated fungi were belonging to the genera:Alternaria,Aspergillus,Cephalosporium,Chaetomium,Cladosporium,Colletotrichum,Curvularia,Fusarium,Macrophomina,Mucor,Penicillium,Rhizoctonia,Rhizopus,Sclerotium,Stemphylium,and Verticillium.Assay of the antifungal activity of four ethanolic extracts of clove,cinnamon,garlic,and mint was carried out against the most common fungal species(Aspergillus flavus,A.niger,Fusarium solani,F.oxysporium,and F.moniliforme),which significantly reduced the growth of tested fungi.Clove extract recorded the highest antimicrobial potentiality against the seed-borne fungal species,followed by cinnamon,garlic,and mint.Clove and cinnamon achieved minimum inhibitory concentration(MIC)values less than that of the reference antifungal drug fluconazole.Simultaneously,garlic and mint recorded MIC values equal to or higher than that of control.A combination of clove and cinnamon,clove and garlic,cinnamon and garlic,cinnamon,and mint extracts increased the mean relative activity percentage.They decreased MIC values below their values when used individually;this indicated synergistic interaction between the two extracts.A combination of clove with mint and garlic with mint recorded a decrease in the percentage of mean relative activity and an increase in MIC values than their values when used individually,indicating antagonistic interaction between them.

Fungi associated with wheat seed discolouration and abnormalities in <i>in-vitro</i>study

The main aim of present study is to ascertain the fungal species and their effect on germination associated with wheat seeds. Seeds of three varieties WH896, PBW-373 and HD264 of wheat (Triticum aestivum) were collected from Quarsi Agriculture Farm Aligarh. These three seed samples of wheat showing different forms of discouloration and abnormalities were screened for associated fungi. Microscopic examination of wheat seeds reveals that seeds of all the varieties of wheat possess injuries to varying extent. Detailed examination of the seeds has shown that the seeds can be classified on the basis of extent of injury in the three categories viz., seeds having minor cracks, cracks without exposed embryo and cracks with exposed embryo. Seed soaking and washing techniques were also employed. Fusarium moniliforme and Alternaria alternata were isolated from all the categories of seed tested. Floating mycelial bits and conidia of Alternaria, Fusarium, Drechslera, Curvularia lunata, Mucor were found in all the three varieties of wheat. The seeds were subjected to visual observation and examination under stereoscopic microscope. These findings are to study and detect the phytopathogenic mycoflora which causes damage and loss to our seeds and crops.

Seedling Production from Seeds of a Wild Ecotype of Vetiver Grass (<i>Vetiveria zizanioides</i>L.) in Southern China

Vetiver grass (Vetiveria zizanioides L.) is widely used for soil and water conservation, and land management. In practice, all vetiver seedlings are propagated via ramets or tillers, which cannot meet the market demand and would also destroy the original habitat. Most vetiver genotypes flower but do not produce seeds. A wild ecotype of vetiver grass originated in southern China is fertile, but the rate of seed germination is very low. This study aimed to develop a novel method to improve its seed germination and seedling establishment. In the field, the inflorescences of wild vetiver were wrapped using a transparent plastic bag with a pot containing wet soils. The effects of inflorescence bagging and Tween 80 application on seed germination and seedling growth were examined. The results showed that seed development was characterized by low seed setting rate (19.2%), uneven maturity time, easy shedding (more than 95% of spikelets shed off 20 days after flowering), therefore difficult harvest of viable seeds. Bagging the inflorescence with moist soils in pot ensured the mature seeds falling onto the nursery soil surface and absorbing water for germination while the immature seeds continued to grow on the inflorescence. Bigging not only improved seed development and maturity, saved the procedure of seed collection and storage, but also provided a humid micro-environment for seed germination and seedling growth. Tween 80 as a surfactant promoted seed water absorption, germination and seedling growth. This simple and novel method has integrated the procedures of seed collection, storage, germination and seedling establishment, and enables the production of a large number of healthy seedlings. The possible reasons for the degeneration and disappearance of the original population were also discussed from the perspective of the disadvantages of vetiver propagation.

RAPD marker linked with sbm-1, a gene conferring resistance to pea seed-born mosaic virus

DNA markers linked with trait of disease-resistance offer a very useful tool forselection of putative disease-resistant progeny and cloning disease-resistant genes.Peaseed-born mosaic virus(PSbMV)is spread mainly through planting infected pea seeds andby non-persistent aphid transmission.Three strains of PSbMV have been identified,designated as P-1,L and P-4.Strain P-1 is most widely distributed.Four recessive

环介导等温扩增方法在食品中沙门菌检测的应用和评价

目的将环介导等温扩增检测方法应用于食品中沙门菌的检验,并在检测方法特异性、灵敏度等方面与实时荧光PCR和传统检测方法进行比较。方法针对沙门菌属高度保守的fimY基因设计环介导等温扩增检测引物并优化反应体系,在特异性、灵敏度和实际样品检测等方面与实时荧光PCR及传统检测方法比对。结果本研究建立的LAMP方法检测沙门菌93株和非目标菌31株,具有良好的特异性。在纯培养、无需增菌情况下,其检测灵敏度为6.4×102cfu/ml,与实时荧光PCR方法相当。食品基质添加试验中,环介导等温扩增方法检测低限为2 cfu/25 g样品;对45份实际食品样品检测结果表明,该方法实际样品检出率为11.1%,与实时荧光PCR及传统方法检测结果一致。结论本研究建立的沙门菌环介导等温扩增检测方法具有良好的特异性,检测灵敏度与实时荧光PCR相当,适用于沙门菌的快速筛选。