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41.
Chitra B. Nair K. N. Anith Janardhanan Sreekumar 《World journal of microbiology & biotechnology》2007,23(8):1183-1187
Four rhizobacterial strains and acibenzolar-S-methyl (ASM), a chemical activator, which suppressed foliar blight of amaranthus (Amaranthus tricolor L.) caused by Rhizoctonia solani Kühn were evaluated for their effect on plant growth. The experiments were performed both under sterile and non-sterile soil
conditions, in the presence or absence of the pathogen. In all cases, plants treated with ASM showed significant reduction
in growth, as determined by shoot length, and shoot and root dry weight when compared to other treatments. The growth retardation
effect of ASM was more profound with respect to shoot length. Reduction in shoot length was least when plants were treated
with a combination of the chemical activator and Pseudomonas putida 89B61 under non-sterile soil conditions in the absence of the pathogen. Both under sterile and non-sterile soil conditions,
in the presence of the pathogen, reduction in shoot length due to application of ASM was diminished significantly when plants
were treated with rhizobacterial strain Pseudomonas fluorescens PN026R. Combined use of plant growth-promoting rhizobacteria (PGPR) and ASM was found to be beneficial as the growth retardation
effect of the plant defense activator was reduced by the growth-promoting ability of the rhizobacteria. 相似文献
42.
D‐X. Wu R‐S. Zhang X. Han J‐X. Wang M‐G. Zhou C‐J. Chen 《The Annals of applied biology》2015,167(2):277-284
An outbreak of grey leaf spot caused by Stemphylium solani was observed on tomato in Shandong Province of China in recent years and brought huge economical losses. Fludioxonil is a phenylpyrrole fungicide with strong antifungal activity against S. solani. To evaluate the risk of S. solani developing fludioxonil resistance, a total of 145 field isolates were examined for sensitivity to fludioxonil by measuring mycelial growth. The baseline sensitivity was distributed as a unimodal curve with a mean EC50 value of 0.0659 (±0.0170) µg mL?1. Five mutants with high resistance to fludioxonil (RF > 1000) were obtained by successively selecting on fludioxonil‐amended plates in the laboratory. All the resistant mutants associated with strongly reduced fitness in mycelial growth, sporulation and pathogenicity. Fludioxonil had positive cross‐resistance with procymidone and iprodione, but there was no cross‐resistance with other fungicides including boscalid, fluazinam, azoxystrobin and flusilazole. Based on the current results, resistance risk of S. solani to fludioxonil could be moderate. This is the first report of baseline sensitivity of S. solani to fludioxonil and its risk assessment. In order to delay the resistance development, it is recommended that fludioxonil can be used as one component of the mixture or fungicides with different modes of action should be alternatively used for this disease management. 相似文献
43.
44.
Endospore forming bacteria were collected from root samples of 35 genera of bedding plants growing in established commercial landscape beds in Central Florida. One hundred and twenty-nine bacterial strains associated with 14 species were identified using fatty acid analysis (Microbial Identification System, MIDI). All strains were evaluated for in vitro inhibition of damping off disease caused by the fungus Rhizoctonia solani. The strongest inhibition of Rhizoctonia by soluble exudates in cocultivation was observed with strains belonging to six species: B. cereus, B. pumilus, B. thuringiensis, L. sphaericus, B. amyloliquefaciens, and B. subtilis. Most strains that inhibited Rhizoctonia growth in cocultivation also inhibited growth via volatile compounds. All 129 strains were evaluated for ability to protect impatiens plants from subsequent challenge infection by Rhizoctonia solani. Certain strains of endospore forming bacteria also enhanced plant growth. It is apparent from this study that the Bacillus community associated with bedding plants in established planting beds produce soluble antifungal compounds, volatile antifungal compounds, and enhance plant growth. In developing biological control, it may be a more practical approach to promote or enhance a natural, multifaceted community of Bacillus strains within our planting beds. 相似文献
45.
马铃薯抗菌肽SN1是一种新型抗菌肽。为明确SN1是否抑制小麦重要土传真菌小麦纹枯菌(禾谷丝核菌)、小麦根腐菌(平脐蠕孢菌)的生长,本文克隆了马铃薯抗菌肽基因SN1的全长编码序列,将该基因编码序列亚克隆到原核表达载体pGEX-4T-1上,构建成GST-SN1融合蛋白表达载体。经异丙基-β-D-硫代半乳糖苷(IPTG)诱导,获得了以包涵体形式表达的GST-SN1重组蛋白。经过裂解、洗涤、溶解、复性等处理,获得了纯化的GST-SN1融合蛋白。体外抑菌试验表明,SN1显著抑制禾谷丝核菌、平脐蠕孢菌菌丝生长,可作为上述植物病害抗性育种的潜在基因。 相似文献
46.
Enhanced fungal resistance in transgenic cotton expressing an endochitinase gene from Trichoderma virens 总被引:2,自引:0,他引:2
Emani C Garcia JM Lopata-Finch E Pozo MJ Uribe P Kim DJ Sunilkumar G Cook DR Kenerley CM Rathore KS 《Plant biotechnology journal》2003,1(5):321-336
Mycoparasitic fungi are proving to be rich sources of antifungal genes that can be utilized to genetically engineer important crops for resistance against fungal pathogens. We have transformed cotton and tobacco plants with a cDNA clone encoding a 42 kDa endochitinase from the mycoparasitic fungus, Trichoderma virens. Plants from 82 independently transformed callus lines of cotton were regenerated and analysed for transgene expression. Several primary transformants were identified with endochitinase activities that were significantly higher than the control values. Transgene integration and expression was confirmed by Southern and Northern blot analyses, respectively. The transgenic endochitinase activities were examined in the leaves of transgenic tobacco as well as in the leaves, roots, hypocotyls and seeds of transgenic cotton. Transgenic plants with elevated endochitinase activities also showed the expected 42 kDa endochitinase band in fluorescence, gel-based assays performed with the leaf extracts in both species. Homozygous T2 plants of the high endochitinase-expressing cotton lines were tested for disease resistance against a soil-borne pathogen, Rhizoctonia solani and a foliar pathogen, Alternaria alternata. Transgenic cotton plants showed significant resistance to both pathogens. 相似文献
47.
In December 2003, a severe general yellowing and death of the fronds of date palm (Phoenix dactylifera) occurred in a grove in the vicinity of Kazeron district, west of Fars province, Iran. Fusarium solani was isolated from the crown, and xylem rays sampled from the trunk 1.5 m above soil level. In pathogenicity tests using artificially infested soil and 1‐year‐old date palm seedlings, an isolate from the trunk (FST) induced general chlorosis and death of seedlings 25–28 days after inoculation. Similar results were obtained when seedlings were planted in naturally infested soil. In both procedures, distal portions of the roots and crown were affected. The fungus was re‐isolated from the crown and leaf bases of the inoculated seedlings. This is the first report of a serious disease of date palm, which we call yellow death, incited by F. solani in Iran. 相似文献
48.
49.
Control of blast and sheath blight diseases of rice using antifungal metabolites produced by Streptomyces sp. PM5 总被引:2,自引:2,他引:0
Vaiyapuri R. Prabavathy Narayanasamy Mathivanan Kandasamy Murugesan 《Biological Control》2006,39(3):313-319
Two antifungal aliphatic compounds, SPM5C-1 and SPM5C-2 with a lactone and ketone carbonyl unit, respectively obtained from Streptomyces sp. PM5 were evaluated under in vitro and in vivo conditions against major rice pathogens, Pyricularia oryzae and Rhizoctonia solani. These compounds were dissolved in distilled water/medium to get the required concentrations. The well diffusion bioassay indicated that the of SPM5C-1 remarkably inhibited the mycelial growth of P. oryzae and R. solani in comparison to SPM5C-2. Though SPM5C-2 showed low antifungal activity against P. oryzae, it was not active against R. solani. Further, SPM5C-1 completely inhibited the growth of P. oryzae and R. solani at concentrations of 25, 50, 75 and 100 μg/ml. Greenhouse experiments revealed that spraying of SPM5C-1 at 500 μg/ml on rice significantly decreased blast and sheath blight development by 76.1% and 82.3%, respectively, as compared to the control with a corresponding increase in rice grain yield. 相似文献
50.
Y. Chen A.‐F. Zhang W.‐X. Wang Y. Zhang T.‐C. Gao 《The Annals of applied biology》2012,161(3):247-254
Thifluzamide is a SDHI (succinate dehydrogenase inhibitor) fungicide, which interferes with succinate ubiquinone reductase in the mitochondrial electron transport chain of fungi. Presently, jinggangmycin is the major fungicide extensively used for the control of rice sheath blight caused by Rhizoctonia solani and resistance to jinggangmycin was first reported to occur in China. A total of 128 isolates of R. solani from Anhui Province of China were characterised for the baseline sensitivity to thifluzamide. The isolates were very sensitive to thifluzamide and the baseline sensitivity curve was unimodal with an average EC50 value of 0.058 ± 0.012 µg mL?1. However, EC50 values of boscalid (another SDHI fungicide) for inhibition of mycelial growth of 22 arbitrarily selected R. solani isolates ranged from 1.89 to 2.68 µg mL?1. Thifluzamide applied at 110 µg mL?1 exhibited excellent protective and curative activity against rice sheath blight and provided 81.1–91.0% protective or curative control efficacy. In field trials in 2010 and 2011, control efficacies of thifluzamide at 82 g.a.i ha?1 15 and 30 days after second application were 84.2% and 86.7%, respectively, suggesting excellent activity against sheath blight. There was a statistically significant difference in the efficacy between thifluzamide and boscalid or jinggangmycin. These results suggested that thifluzamide should be a good alternative fungicide to jinggangmycin for the control of rice sheath blight. 相似文献