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1.
Xiaolu Chen Jie Ge Deying Ma Lijuan Ma Wei Liu Song Qiang 《Journal of Phytopathology》2017,165(6):355-360
The chickpea (Cicer arietinum L.) is the primary cultivated rain fed crop in the Xinjiang region of Northwest China. In 2007, chickpeas suffered an epidemic disease that caused significant economic losses. To identify the causative agent, debris and seeds of infected chickpea plants were collected from cultivated fields. We isolated and purified the responsible pathogen and tested its pathogenicity both in greenhouse and in the field. Morphological analysis using tissue culture as well as molecular techniques confirmed that the pathogen was the blight fungus Ascochyta rabiei. 相似文献
2.
Xie‐Feng Yao Jin‐Hua Xu Binoy Babu Mathews L. Paret Xing‐Ping Yang 《Journal of Phytopathology》2015,163(4):314-319
Gummy stem blight (GSB) is one of the most destructive foliar diseases of cucurbits, worldwide. To identify and characterize the pathogen which causes GSB on watermelon and muskmelon in East China, morphological characteristics, pathogenicity assays as well as sequence characterization of the rDNA internal transcribed spacer (ITS) were performed on 41 isolates collected from Jiangsu, Zhejiang, Anhui and Jiangxi provinces. The mycelia of all the isolates were white on top and olivaceous green to black with concentric circles at the bottom on potato‐dextrose agar medium. The isolates differed significantly on aggressiveness based on pathogenicity assays. rDNA‐ITS sequences and phylogenetic analysis confirmed the isolates as Didymella bryoniae. The isolates were found to be highly identical with the exception of 13 isolates, which had a guanine substitution instead of adenine at position 131 of the ITS. 相似文献
3.
Genetic diversity and population structure among 29 isolates of Ascochyta rabiei (AR) obtained from diseased chickpea plants in six different geographical origins in Iran was characterized by MAT and rep‐PCR (BOX/ERIC/REP) markers. Both mating types were found in all six populations, and the frequencies of mating types were variable between populations. The majority of the isolates belonged to Mat1‐1 (58.12%) with the remainder (41.88%) being Mat1‐2. A dendrogram was calculated with Jaccard's similarity coefficients with unweighted pair group method clustering (UPGMA) for the combination of rep‐PCR results, AR strains were differentiated into four clusters (A–D) at 60% similarity level. ERIC, REP and BOX showed a total of 19, 37 and 24 alleles per locus, respectively. Gene diversity (He) and Shannon's information index (I) were the highest in the REP (He = 0.82; I = 2.11), while the lowest values were estimated for the ERIC (He = 0.42; I = 1.3). Our result showed that among the three techniques studied, REP‐PCR produced the most complex amplified banding patterns, which reflected a high degree of diversity among the Iranian AR strains. ERIC‐PCR was the least discriminating method, and BOX‐PCR was intermediate. To the best our knowledge, this is first study of assessment of genetic diversity of AR isolates by rep‐PCR markers. 相似文献
4.
Frank M. Dugan Hajime Akamatsu Shari L. Lupien Weidong Chen Martin L. Chilvers Tobin L. Peever 《Biocontrol Science and Technology》2009,19(5):537-545
In 2004–2005, application of non-amended suspensions of Aureobasidium pullulans conidia to post-harvest chickpea debris resulted in 37.9% fewer Ascochyta blight lesions on chickpea test plants relative to controls. Analogous tests in 2006–2007 resulted in 38.4% fewer lesions. Ascospores released from debris were predominantly Davidiella sp. (anamorph, Cladosporium sp.), followed by Didymella rabiei (anamorph, Ascochyta rabiei, agent of Ascochyta blight). 相似文献
5.
Lili Shen Fenglong Wang Yanhua Liu Yumei Qian Jinguang Yang Huiqing Sun 《Journal of Phytopathology》2013,161(4):293-294
Suppression of Tobacco Mosaic Virus (TMV) by B. amyloliquefaciens Ba33 was evaluated on Nicotiana tabacum by spraying before (①), after (②) and simultaneously with (③) TMV inocula. The results suggested that Ba33 treatments reduced local necrotic lesion number and disease index, showing ③ treatment was the best and ① treatment was better than ② treatment in TMV suppression. It also showed Ba33 virus‐contaminated scissors could be disinfected by dipping. Field trials showed that Ba33 had an inhibitory effect of 48.59% in 2009 and 50.54% in 2010, close to the effect of Ningnanmycin, a registered antiviral agent in tobacco. In conclusion, Ba33 might be used as a soil disinfector and an antiviral agent against TMV. 相似文献
6.
Xuan Fan Jing Zhang Long Yang Qinghua Zhang Guoqing Li 《Journal of Phytopathology》2012,160(10):595-598
In 2010 and 2011, a disease exhibiting characteristics of white mold was found on Sedum sarmentosum, a crassulaceous weed under canopies of tea trees, in Zhushan County, Hubei Province, China. Based on the cultural and morphological characteristics, the pathogen was identified as Sclerotinia nivalis Saito. In the phylogenetic tree inferred from the internal transcribed spacer (ITS)‐rDNA sequences, the pathogen was clustered with five previously characterized isolates of S. nivalis, forming a unique clade, thus confirming the morpho‐cultural identification. Koch’s postulates were fulfilled by pathogenicity tests using the isolate SsSn‐24 and Let‐19 of S. nivalis on plants of S. sarmentosum. To our knowledge, this is the first report of S. nivalis on S. sarmentosum in the family Crassulaceae. 相似文献
7.
Omar Atik Michael Baum Ahmed El‐Ahmed Seid Ahmed Mathew M. Abang Mohammad M. Yabrak Samer Murad Siham Kabbabeh Aladdin Hamwieh 《Journal of Phytopathology》2011,159(6):443-449
Chickpea fields were surveyed in nine major chickpea‐growing provinces of Syria in 2008 and 2009 to determine the prevalence and severity of Ascochyta blight, and the distribution of Didymella rabiei mating types (MATs) in the country. A total of 133 Ascochyta rabiei isolates were assayed for mating type, including isolates from older collections that date back to 1982. Multiplex MAT‐specific PCR with three primers was used for MAT analysis. Out of the 133 tested isolates, 64% were MAT1‐1 and 36% were MAT1‐2. Both MATs were found in six provinces but MAT1‐1 alone was found in three provinces. Chi‐squared analysis was used to test for a 1 : 1 ratio of MAT frequencies in all samples. The MAT ratios in the six provinces were not significantly different from 1 : 1, suggesting that there is random mating of the pathogen population under natural conditions. The presence of the two MATs is expected to play a role in the evolution of novel virulence genes that could threaten currently resistant chickpea varieties. Overall analysis of the 133 isolates showed a significant deviation from the 1 : 1 ratio with almost twice as many MAT1‐1 isolates than MAT1‐2 isolates, which indicates a competitive advantage associated with MAT1‐1 in Syria. However, the overall picture of an unequal frequency in MATs indicates that there may be limited sexual recombination occurring in the Syrian population. 相似文献
8.
A study of nematodes associated with the large larch bark beetle Ips cembrae (Heer 1836) was carried out at three locations in the Czech Republic. The proportion of beetles infested by endoparasitic nematodes (representatives of genera Contortylenchus, Parasitylenchus, Cryptaphelenchus and Parasitorhabditis) ranged from 29.9 to 50.9%. Significant differences were determined in nematode infestation levels among locations, generations and sampling methods. No differences were found in infestation rates between males and females. The percentage of bark beetles with phoretic nematodes ranged from 18 to 42.9%. Phoretic nematodes directly found under elytra, on wings and between body segments of the bark beetles belong to the genus Micoletzkya. However, adults and juveniles of other two phoretic species Laimaphelenchus penardi and Bursaphelenchus sp. were found in the gallery frass of I. cembrae. Infestation by phoretic nematodes positively correlated with the presence of mites under elytra. 相似文献
9.
Xueqin Rao Yuan Li Jie Sun Xia Li Menghan Li Meimei Xiang 《Journal of Phytopathology》2015,163(4):324-329
Orchids are some of the most important ornamental flowers. Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV) are the most prevalent and economically important viruses affecting orchids in China. In this study, 20 CymMV and 28 ORSV isolates were selected for genetic diversity analysis. The CymMV isolates shared 84.6–100% and 89.5–100% identities of coat protein (CP) at the nucleotide (nt) and amino acid (aa) levels, respectively. The identities of ORSV isolates were 96.4–100% (nt) and 92.5–99.4% (aa). The CP genes of CymMV were found to have genetic diversity, and the CP genes of ORSV were genetically conservative. These results can aid in designing effective disease‐control strategies. 相似文献
10.
Xizhuo Wang Laifa F. Wang Chungen Piao Jianwei Ma Yutong Shang Yong Li Minwei Guo 《Journal of Phytopathology》2013,161(6):426-429
Angelica dahurica is an important Chinese herbal medicine plant, and its rhizome is of high medicinal value. In recent years, a severe decline in yield has been observed in Bozhou City (China's largest A. dahurica producing area), Anhui province, China. It showed symptoms of decline, stunting, yellowing and many galls in the roots, which was the characterization of infestation by root‐knot nematodes. A survey of root‐knot nematodes on its roots was conducted in this area from June to September, 2011. Based on our results, the nematode species on A. dahurica was identified as Meloidogyne arenaria by the morphological, biochemical and molecular methods. To our knowledge, this is the first report of M. arenaria on A. dahurica in China. 相似文献
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12.
Min Yue Zhang Tsz Kin Fung Fang Yuan Chen Chor Sang Chim 《Journal of cellular and molecular medicine》2013,17(10):1282-1290
13.
Muhammad Ashfaq Muhammad Asif Zahid Iqbal Anjum Yusuf Zafar 《Molecular ecology resources》2013,13(4):573-582
Although two plastid regions have been adopted as the standard markers for plant DNA barcoding, their limited resolution has provoked the consideration of other gene regions, especially in taxonomically diverse genera. The genus Gossypium (cotton) includes eight diploid genome groups (A–G, and K) and five allotetraploid species which are difficult to discriminate morphologically. In this study, we tested the effectiveness of three widely used markers (matK, rbcL, and ITS2) in the discrimination of 20 diploid and five tetraploid species of cotton. Sequences were analysed locus‐wise and in combinations to determine the most effective strategy for species identification. Sequence recovery was high, ranging from 92% to 100% with mean pairwise interspecific distance highest for ITS2 (3.68%) and lowest for rbcL (0.43%). At a 0.5% threshold, the combination of matK+ITS2 produced the greatest number of species clusters. Based on ‘best match’ analysis, the combination of matK+ITS2 was best, while based on ‘all species barcodes’ analysis, ITS2 gave the highest percentage of correct species identifications (98.93%). The combination of sequences for all three markers produced the best resolved tree. The disparity index test based on matK+rbcL+ITS2 was significant (P < 0.05) for a higher number of species pairs than the individual gene sequences. Although all three barcodes separated the species with respect to their genome type, no single combination of barcodes could differentiate all the Gossypium species, and tetraploid species were particularly difficult. 相似文献
14.
Thaddeus Metz 《Developing world bioethics》2018,18(3):233-240
Many countries in Africa, and more generally those in the Global South with tropical areas, are plagued by illnesses that the wealthier parts of the world (mainly ‘the West’) neither suffer from nor put systematic effort into preventing, treating or curing. What does an ethic with a recognizably African pedigree entail for the ways various agents ought to respond to such neglected diseases? As many readers will know, a characteristically African ethic prescribes weighty duties to aid on the part of those in a position to do so, and it therefore entails that there should have been much more contribution from the Western, ‘developed’ world. However, what else does it prescribe, say, on the part of sub‐Saharan governments and the African Union, and are they in fact doing it? I particularly seek to answer these questions here, by using the 2013‐16 Ebola crisis in West Africa to illustrate what should have happened but what by and large did not. 相似文献
15.
Louis M. Weiss Melanie T. Cushion Elizabeth Didier Lihua Xiao Francine Marciano‐Cabral Anthony P. Sinai Olga Matos Enrique J. Calderon Edna S. Kaneshiro 《The Journal of eukaryotic microbiology》2013,60(3):298-308
The 12th International Workshops on Opportunistic Protists (IWOP‐12) was held in August 2012 in Tarrytown, New York. The objectives of the IWOP meetings are to: (1) serve as a forum for exchange of new information among active researchers concerning the basic biology, molecular genetics, immunology, biochemistry, pathogenesis, drug development, therapy, and epidemiology of these immunodeficiency‐associated pathogenic eukaryotic microorganisms that are seen in patients with AIDS and (2) foster the entry of new and young investigators into these underserved research areas. The IWOP meeting focuses on opportunistic protists, e.g. the free‐living amoebae, Pneumocystis, Cryptosporidium, Toxoplasma, the Microsporidia, and kinetoplastid flagellates. This conference represents the major conference that brings together research groups working on these opportunistic pathogens. Slow but steady progress is being achieved on understanding the biology of these pathogenic organisms, their involvement in disease causation in both immune‐deficient and immune‐competent hosts, and is providing critical insights into these emerging and reemerging pathogens. This IWOP meeting demonstrated the importance of newly developed genomic level information for many of these pathogens and how analysis of such large data sets is providing key insights into the basic biology of these organisms. A great concern is the loss of scientific expertise and diversity in the research community due to the ongoing decline in research funding. This loss of researchers is due to the small size of many of these research communities and a lack of appreciation by the larger scientific community concerning the state of art and challenges faced by researchers working on these organisms. 相似文献
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17.
Zelalem Mersha Shouan Zhang Yuqing Fu Xiaodan Mo Richard N. Raid Bernhard Hau 《Journal of Phytopathology》2013,161(3):154-164
Downy mildew, caused by the oomycete pathogen Peronospora belbahrii, is a devastating foliar disease of basil in the United States and worldwide. Currently there are very few chemistries or organic choices registered to control this disease. In this study, two systemic acquired resistance (SAR) inducers, acibenzolar‐S‐methyl (ASM) and β‐aminobutyric acid (BABA), were evaluated for their in vitro effects on the pathogen, for their potential to control basil downy mildew in greenhouses, and for changes in peroxidase activity in basil plants treated with these two SAR inducers. No significant inhibition of sporangial germination was detected in water agar amended with ASM at concentrations lower than 100 mg/l or with BABA at concentrations lower than 500 mg/l. Efficacy of ASM and BABA in greenhouses varied depending on the rate, method and timing of application. The area under the disease progress curve (AUDPC) of disease severity was significantly reduced compared to the non‐treated control when ASM was sprayed (in all experiments) or drenched (in one out of two experiments) pre‐, or pre‐ + post‐inoculation at rates of 25–400 mg/l. Three weekly post‐inoculation sprays of ASM at the rate of 50 mg/l reduced AUDPC by 93.0 and 47.2% when started 3 and 7 days after inoculation (DAI), respectively. The AUDPC of disease severity was also significantly reduced when BABA was sprayed pre‐ + post‐inoculation at rates of 125–500 mg/l. According to the prediction using a log‐logistic function, 50% maximum disease protection was achieved at a concentration of 27.5 mg/l of ASM. Basil plants treated with these two SAR inducers and challenged with the pathogen showed significantly higher peroxidase activity than the non‐treated control at 8 DAI. Temporally, the highest activity of peroxidase was detected at 8 DAI, decreased at 15 DAI and waned further at 23 DAI. 相似文献
18.
Gábor Mészáros Elisabeth Petautschnig Hermann Schwarzenbacher Johann Sölkner 《Animal genetics》2015,46(1):65-68
Genomic regions associated with coat color and pigmented areas of the head were identified for Fleckvieh (dual‐purpose Simmental), a red‐spotted and white‐headed cattle breed. Coat color was measured with a chromameter, implementing the CIELAB color space and resulting in numerical representation of lightness, color intensity, red/green and blue/yellow color components, rather than subjective classification. Single marker regression analyses with fixed effects of the sex and barn were applied, and significant regions were determined with the local false discovery rate methodology. The PMEL and ERBB3 genes on chromosome 5 were in the most significant region for the color measurements. In addition to the blue/yellow color component and color intensity, the AP3B2 gene on chromosome 21 was identified. Its function was confirmed for similar traits in a range of model species. The KIT gene on chromosome 6 was found to be strongly associated with the inhibition of circum‐ocular pigmentation and pigmented spots on the cheek. 相似文献
19.
Stephen K. Donovan 《Lethaia: An International Journal of Palaeontology and Stratigraphy》2021,54(1):1-3
‘Train crash crinoids’ represent an unusual mode of preservation of crinoid columns, superficially resembling to the carriages of a crashed train. They were exhumed from the White Peak (Mississippian limestones) of the Peak District in the Treak Cliff area of Castleton, Derbyshire, north‐central England, and were presented by Broadhurst & Simpson as part of a varied suite of observations supporting the recognition of an ancient apron reef (= fore‐reef slope). A re‐examination of these specimens shows that they were not live crinoids at or near the reef crest, but were recently dead specimens, recumbent on the sediment surface. Something triggered their movement into deeper water, and some travelled downslope parallel to the direction of movement and broke into a ‘train crash pattern’ when the lower end impacted on an immovable object. 相似文献
20.
Christina Bock Wei Luo Wolf‐Henning Kusber Eberhard Hegewald Marie Pažoutová Lothar Krienitz 《Journal of phycology》2013,49(2):329-339
The subfamily Crucigenioideae was traditionally classified within the well‐characterized family Scenedesmaceae (Chlorophyceae). Several morpho‐logical revisions and questionable taxonomic changes hampered the correct classification of crucigenoid species resulting in a high number of synonymous genera. We used a molecular approach to determine the phylogenetic position of several Tetrastrum and Crucigenia species. The molecular results were correlated with morphological and ontogenetic characters. Phylogenetic analyses of the SSU rDNA gene resolved the position of Tetrastrum heteracanthum and T. staurogeniaeforme as a new lineage within the Oocystis clade of the Trebouxiophyceae. Crucigenia tetrapedia, T. triangulare, T. punctatum, and T. komarekii were shown to be closely related to Botryococcus (Trebouxiophyceae) and were transferred to Lemmer‐mannia. Crucigenia lauterbornii was not closely related to the other Crucigenia strains, but was recovered within the Chlorella clade of the Trebouxiophyceae. 相似文献