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排序方式: 共有989条查询结果,搜索用时 62 毫秒
891.
Mohamed T. El-Saadony Ahmed M. Saad Azhar A. Najjar Seraj O. Alzahrani Fatmah M. Alkhatib Manal E. Shafi Eman Selem El-Sayed M. Desoky Sarah E.E. Fouda Amira M. El-Tahan Mokhles A.A. Hassan 《Saudi Journal of Biological Sciences》2021,28(8):4461-4471
Fusarium species threaten wheat crops around the world and cause global losses. The global trend is toward using biological materials such as selenium (Se) in nano form to control these fungi. Bulk selenium is toxic and harmful at high doses; however, selenium nanoparticles are safe; therefore, the aim of this study to employ the biological selenium nanoparticles (BioSeNPs) synthesized by Lactobacillus acidophilus ML14 in controlling wheat crown and root rot diseases (CRDs) induced by Fusarium spp., especially Fusarium culmorum and Fusarium graminearum, and their reflection on the growth and productivity of wheat. The ability of BioSeNPs to suppress the development and propagation of F. culmorum and F. graminearum and the CRDs incidence were also investigated. The obtained BioSeNPs were spherical with a size of 46 nm and a net charge of –23.48. The BioSeNPs significantly scavenged 88 and 92% of DPP? and ABT? radicals and successfully inhibited the fungal growth in the range of 20–40 µg/mL; these biological activities were related to the small size of BioSeNPs and the phenolic content in their suspension. Under greenhouse conditions, the wheat supplemented with BioSeNPs (100 µg/mL) was significantly reduced the incidence of CRDs by 75% and considerably enhanced plant growth, grain quantity and quality by 5–40%. Also, photosynthetic pigments and gas exchange parameters were significantly increased as compared to chemical selenium nanoparticles (Che-SeNPs) and control. This study results could be recommended the use of BioSeNPs (100 µg/mL) in reducing CRDs incidence and severity in wheat plants, enhancing their tolerance with drought and heat stress, and increasing their growth and productivity as compared to control and Che-SeNPs. 相似文献
892.
The effects of race-specific resistance as conditioned by Rps genes (rps, Rps1-k, Rps2, Rps3, Rps6) in two genetic backgrounds (Williams & Harosoy) on accumulation of soluble peroxidases were determined by a soybean peroxidase
capture assay (SPCA) after inoculation with P. sojae races 2, 7, or 25. Peroxidase activity increased in all isolines during the 72 h after inoculation, but reactions varied
depending on time after inoculation, genetic background, Rps gene and P. sojae race. Peroxidase activity was higher in race-specific resistant than in susceptible reactions at 72 h. after inoculation,
except for plants with the Rps2 gene which confers a unique form of root resistance in addition to the whole plant race-specific resistance. Williams isolines
had larger increases in peroxidase activity than Harosoy isolines when data were averaged across Rps genes, and was most evident when plants were inoculated with race 2. When soybeans were inoculated with race 7 Rps1-k resistant plants had the highest increase in peroxidase activity, but Rps2 susceptible plants had a significantly higher peroxidase activity than plants with rps, Rps3, and Rps6 that were also susceptible. Results from inoculations with race 25 were somewhat different, Rps2 resistant plants had the highest increase in peroxidase activity; however, plants with the Rps3 or Rps6 gene that were also resistant did not have a significantly higher peroxidase activity than susceptible plants with the rps or Rps1-k gene. 相似文献
893.
以酸枣无菌苗叶片为外植体,研究了培养条件对不定梢再生及不定梢玻璃化的影响.结果表明,叶片在加有细胞分裂素TDZ的诱导培养基(培养基Ⅰ)上连续培养,可诱导不定芽形成,但不能进一步发育成不定梢;而在诱导培养基Ⅰ上培养2周后转移到不加TDZ的培养基Ⅱ上,可获得不定芽伸长的不定梢.培养基Ⅱ的基本培养基组成影响不定芽(梢)的玻璃化症状:MS培养基产生玻璃化的不定芽(梢),而WPM培养基产生正常不定芽梢;光培养条件的变化对玻璃化症状的发生没有影响.不定芽(梢)玻璃化的发生可能与培养基中铵或硝酸铵的浓度有关,在不定芽伸长发育阶段,培养基中高浓度的铵导致了玻璃化苗的发生. 相似文献
894.
JIN‐YAN FAN LI‐YUN GUO JIAN‐PING XU YONG LUO THEMIS J. MICHAILIDES 《The Journal of eukaryotic microbiology》2010,57(2):206-212
ABSTRACT. The genetic variation among 128 isolates of Monilinia fructicola (Fungi, Ascomycota, Helotiales) from China was analyzed using Inter‐Simple Sequence Repeat (ISSR) markers and compared with those of samples from California, USA and New Zealand. A total of 72 reproducible DNA fragments were scored, of which 87.5% (63/72) were polymorphic. The Nei's gene diversity and Shannon's diversity indices of three Chinese regional populations were very similar to that from California. However, several differences were observed among geographic populations of M. fructicola from both within China and between China and California. The analysis of molecular variance (AMOVA) of isolates from different geographic locations suggested that most of the observed genetic variation was found within populations. Results of this study are inconsistent with the hypothesis that the Chinese populations of M. fructicola were derived from a single or few recent migrants from other countries. Instead, our results suggest that M. fructicola has been in China long before its first official recording in 2003. 相似文献
895.
896.
Bart Cottyn Kim Heylen Jeroen Heyrman Katrien Vanhouteghem Ellen Pauwelyn Peter Bleyaert Johan Van Vaerenbergh Monica Höfte Paul De Vos Martine Maes 《Systematic and applied microbiology》2009
Bacterial midrib rot of greenhouse-grown butterhead lettuce (Lactuca sativa L. var. capitata) is an emerging disease in Flanders (Belgium) and fluorescent pseudomonads are suspected to play an important role in the disease. Isolations from infected lettuces, collected from 14 commercial greenhouses in Flanders, yielded 149 isolates that were characterized polyphasically, which included morphological characteristics, pigmentation, pathogenicity tests by both injection and spraying of lettuce, LOPAT characteristics, FAME analysis, BOX-PCR fingerprinting, 16S rRNA and rpoB gene sequencing, as well as DNA–DNA hybridization. Ninety-eight isolates (66%) exhibited a fluorescent pigmentation and were associated with the genus Pseudomonas. Fifty-five of them induced an HR+ (hypersensitive reaction in tobacco leaves) response. The other 43 fluorescent isolates were most probably saprophytic bacteria and about half of them were able to cause rot on potato tuber slices. BOX-PCR genomic fingerprinting was used to assess the genetic diversity of the Pseudomonas midrib rot isolates. The delineated BOX-PCR patterns matched quite well with Pseudomonas morphotypes defined on the basis of colony appearance and variation in fluorescent pigmentation. 16S rRNA and rpoB gene sequence analyses allowed most of the fluorescent isolates to be allocated to Pseudomonas, and they belonged to either the Pseudomonas fluorescens group, Pseudomonas putida group, or the Pseudomonas cichorii/syringae group. In particular, the isolates allocated to this latter group constituted the vast majority of HR+ isolates and were identified as P. cichorii by DNA–DNA hybridization. They were demonstrated by spray-inoculation tests on greenhouse-grown lettuce to induce the midrib rot disease and could be re-isolated from lesions of inoculated plants. Four HR+ non-fluorescent isolates associated with one sample that showed an atypical midrib rot were identified as Dickeya sp. 相似文献
897.
The genus Armillaria includes harmful fungal pathogens that cause root rot and wood decay in a broad range of host plants throughout the world. The aim of this study was to detect, by means of Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) markers, the level of intraspecific variability within isolates of an Armillaria gallica population sampled from a Quercus spp. stand located in Gravina in Puglia, southern Italy. UPGMA cluster analysis of RAPD profiles generated by decamer primers grouped the isolates in subclusters demonstrating relatively low intraspecific genetic variability. Moreover, RAPD pattern analysis yielded clusters which did not correspond to the groups discriminated by vegetative compatibility tests performed by a previous investigation on the same population. The findings of this research pose the question of whether somatic incompatibility, which involves an undefined number of genes and alleles per gene, might still be considered an effective tool for the epidemiological studies of A. gallica , whereas molecular analyses are more useful for assessing genomic variation within the species. 相似文献
898.
柑橘与枳属间体细胞杂种再生及其对脚腐病抗性的评价 总被引:3,自引:0,他引:3
Page橘柚 (CitrusreticulataBlanco×C .paradisiMacf.)胚性细胞悬浮系原生质体与枳 (Poncirustrifoliata (L .)Raf.)叶肉原生质体经电场诱导融合 ,4~ 5个月再生 15 0余棵小植株。再生植株根系发达 ,叶片具三叶特征。随机检查 2 0余株再生苗根尖染色体数目 ,表明都为四倍体 (2n =4x =36 )。随机取 7株进行RAPD分析 ,表明被检测植株都为杂种。用引起脚腐病的寄生疫霉菌 (PhytophthoraparasiticaDastar)毒素接种体细胞杂种及双亲叶片 ,结果表明 ,Page橘柚中度感病 ,枳高抗 ,体细胞杂种为抗病类型。 相似文献
899.
白腐菌产漆酶的纯化及部分酶学性质 总被引:23,自引:0,他引:23
对白腐菌W 1产生的漆酶粗酶液通过超滤浓缩、分子筛和离子交换层析进行纯化 .用SDS PAGE证明该酶的分子量大约为 6 2 4kD .等电聚焦电泳显示该酶的等电点为 3 5 .酶反应的最适温度为 5 0℃ ,最适pH值为 4 5 .此酶氧化DMP的Km 值为 3 84× 10 -5mol L .金属离子对酶活的影响很大 ,其中K+ 、Mn2 + 、Ag+ 对酶活有促进作用 ,Fe2 + 、Fe3 + 、Hg2 + 、Co2 + 、Ba2 + 等对酶活有明显的抑制作用 .酶对部分染料也有一定的脱色效果 相似文献
900.
Rasmus Dam Wollenberg Teis Esben Sondergaard Mikkel Rank Nielsen Simon Knutsson Tobias Bruun Pedersen Klaus Ringsborg Westphal Reinhard Wimmer Donald Max Gardiner Jens Laurids Sørensen 《Fungal biology》2019,123(1):10-17
Fusarium pseudograminearum is a significant pathogen of cereals in arid regions worldwide and has the ability to produce numerous bioactive secondary metabolites. The genome sequences of seven F. pseudograminearum strains have been published and in one of these strains, C5834, we identified an intact gene cluster responsible for biosynthesis of the cyclic lipopeptide fusaristatin A. The high level of sequence identity of the fusaristatin cluster remnant in strains that do not produce fusaristatin suggests that the absence of the cluster evolved once, and subsequently the resulting locus with the cluster fragments became widely dispersed among strains of F. pseudograminearum in Australia. We examined a selection of 99 Australian F. pseudograminearum isolates to determine how widespread the ability to produce fusaristatin A is in F. pseudograminearum. We identified 15 fusaristatin producing strains, all originating from Western Australia. Phylogenetic analyses could not support a division of F. pseudograminearum into fusaristatin producing and nonproducing populations, which could indicate the loss has occurred relatively recent. 相似文献