共查询到20条相似文献,搜索用时 31 毫秒
1.
Bo Yang Muhammad H. Rahman Yue Liang Saleh Shah Nat N. V. Kav 《Plant Molecular Biology Reporter》2010,28(2):253-263
Canola (Brassica napus L.) is an agriculturally and economically important crop in Canada, and its growth and yield are frequently influenced by
fungal pathogens. Sclerotinia sclerotiorum is among those fungal pathogens and causes stem rot disease in B. napus whereas it has been reported that Brassica carinata is moderately tolerant to S. sclerotiorum. Jasmonic acid/ethylene (JA/ET) and salicylic acid (SA) are phytohormones that are known to be involved in plant disease
responses. To investigate the defense signaling cascades involved in the interaction of B. napus and B. carinata with S. sclerotiorum, we examined the expression of five orthologs of B. napus genes involved in JA/ET or SA signaling pathways using quantitative RT-PCR. Our results indicated that there are differences
in the timing of JA/ET and SA signaling pathways between B. napus and B. carinata. Our results in these two Brassica species also support previous observations that necrotrophic pathogens trigger JA/ET signaling in response to infection.
Finally, we observed that transgenic canola expressing 1-aminocyclopropane-1-carboxylate-deaminase producing low levels of
ET was relatively more susceptible to S. sclerotiorum than its wild-type counterpart, suggesting that ET inhibits S. sclerotiorum-induced symptom development. 相似文献
2.
Yukiko Matsumoto Masaya Matsumura Sugihiko Hoshizaki Yuki Sato Hiroaki Noda 《Applied Entomology and Zoology》2011,46(3):435-442
The twisted-wing parasite Elenchus japonicus is a major parasitoid of rice planthoppers (Hemiptera: Delphacidae), including the brown planthopper Nilaparvata lugens, the white-backed planthopper Sogatella furcifera, and the small brown planthopper Laodelphax striatellus. Another Elenchus species, E. yasumatsui, which is considered to be synonymous with E. japonicus, has also been described in southern Asia. However, limited biological and molecular data on this important parasitoid of
rice planthoppers are available. In this study, E. japonicas-stylopized planthoppers were obtained from various regions in Asia and Japan. Sequences of the nuclear 18S ribosomal RNA
gene and the mitochondrial cytochrome oxidase I gene of the strepsipterans were analyzed from 40 samples of E. japonicus: 14 from N. lugens, 6 from S. furcifera and 20 from L. striatellus. Sequence analysis of these samples revealed three genotypes of E. japonicus. Of the three types of E. japonicus, one was isolated only from L. striatellus from northern Japan. The other two types were found in all three rice planthopper species collected from a wide area in Asia.
These results suggest that the three different genotypes of Elenchus can be associated with a particular geographical region and/or planthopper species. The relationship between two previously
described Elenchus species and the present three genotypes needs to be elucidated. 相似文献
3.
Tropilaelaps
mercedesae is a serious ectoparasite of Apis
mellifera in China. The aim of this study was to investigate the infestation rates and intensity of T. mercedesae in A. mellifera in China, and to explore the relative importance of climate, district, management practices and beekeeper characteristics
that are assumed to be associated with the intensity of T. mercedesae. Of the 410 participating apiaries, 379 apiaries were included in analyses of seasonal infestation rates and 352 apiaries
were included in multivariable regression analysis. The highest infestation rate (86.3%) of T. mercedesae was encountered in autumn, followed by summer (66.5%), spring (17.2%) and winter (14.8%). In autumn, 28.9% (93) of the infested
apiaries were in the north (including the northeast and northwest of China), 71.1% (229) were in the central and south (including
east, southeast and southwest China), and 306 apiaries (82.9%) were co-infested by both T. mercedesae and Varroa. Multivariable regression analysis showed that geographical location, season, royal jelly collection and Varroa infestation were the factors that influence the intensity of T. mercedesae. The influence of beekeeper’s education, time of beekeeping, operation size, and hive migration on the intensity of T. mercedesa was not statistically significant. This study provided information about the establishment of the linkage of the environment
and the parasite and could lead to better timing and methods of control. 相似文献
4.
5.
Kai-Li Zhang Qing-Song Liu Hou-Xiang Kang Xiao-Mei Liu Xiu-Ping Chen Yu-Fa Peng Yun-He Li 《Insect Science》2020,27(1):49-57
In agro-ecosystems,plants are important mediators of interactions between their associated herbivorous insects and microbes,and any change in plants induced by one species may lead to cascading effects on interactions with other species.Often,such effects are regulated by phytohormones such as jasmonic acid(JA)and salicylic acid(SA).Here,we investigated the tripartite interactions among rice plants,three insect herbivores(Chilo suppressalis,Cnaphalocrocis medinalis or Nilapai-vata lugens),and the causal agent of rice blast disease,the fungus Magnaporthe oryzae.We found that pre-infestation of rice by C.suppressalis or N.lugens but not by C.medinalis conferred resistance to M.oryzae.For C.suppressalis and N.lugens,insect infestation without fungal inoculation induced the accumulation of both JA and SA in rice leaves.In contrast,infestation by C.medinalis increased JA levels but reduced SA levels.The exogenous application of SA but not of JA conferred resistance against M.oryzae.These results suggest that preinfestation by C suppressalis or N.lugens conferred resistance against M.oryzae by increasing SA accumulation.These findings enhance our understanding of the interactions among rice plant,insects and pathogens,and provide valuable information for developing an ecologically sound strategy for controlling rice blast. 相似文献
6.
Sylvain Lerat Amadou H. Babana Mohamed El Oirdi Abdelbassed El Hadrami Fouad Daayf Nathalie Beaudoin Kamal Bouarab Carole Beaulieu 《Plant cell reports》2009,28(12):1895-1903
Streptomyces scabiei is the predominant causal agent of common scab of potato in North America. The virulence of common scab-causing streptomycetes
relies on their capacity to synthesize thaxtomins. In this study, the effects of S. scabiei infection and of thaxtomin A, the main toxin produced by S. scabiei, were tested for the elicitation of plant defense molecules in the model plants tobacco (Nicotiana tabacum) and Arabidopsis thaliana. Tobacco leaves infected with spores of S. scabiei strain EF-35 or infiltrated with purified thaxtomin A produced a blue fluorescent compound that was not detected in leaves
infiltrated with spores of a S. scabiei mutant deficient in thaxtomin A biosynthesis. Thin layer chromatography and high performance liquid chromatography identified
this fluorescent compound as scopoletin, a plant defense phytoalexin. Arabidopsis seedlings grown in liquid medium also excreted
scopoletin as a reaction to S. scabiei and thaxtomin A. The effects of the presence of scopoletin on S. scabiei were also investigated. The phytoalexin scopoletin caused a slight reduction of bacterial growth and a severe decrease of
thaxtomin A production. Scopoletin was shown to inhibit thaxtomin A production by repression of a gene involved in the toxin
biosynthesis. 相似文献
7.
Xanthomonas oryzae pv. oryzae causes bacterial leaf blight, one of the most widespread and destructive bacterial diseases in rice. In order to understand
the gene of zinc uptake regulator (zur) involved in virulence of the pathogen in rice, we generated a mutant OSZRM by homologous suicide plasmid integration. The
mutant failed to grow in NYGB medium supplemented with Zn2+ or Fe3+ at a concentration of 500 μM or 6 mM, whereas the wild-type strain grew well at the same conditions. The zur mutant was hypersensitive to hydrogen peroxide and exhibited reduction catalase activity and the production of extracellular
polysaccharide (EPS). Interestingly, the mutant showed a reduction in virulence on rice but still kept triggering hypersensitive
response (HR) in tobacco. When the mutant was complemented with the zur gene, the response was recovered to wild-type. These results suggested that zur gene is a functional member of the Zur regulator family that controls zinc and iron homeostasis, oxidative stress, and EPS
production, which is necessary for virulence in X. oryzae pv. oryzae.
Wanfeng Yang and Yan Liu contributed equally to this work 相似文献
8.
Genome sequence analysis of Xanthomonas
oryzae pv. oryzae has revealed a cluster of 12 ORFs that are closely related to the gum gene cluster of Xanthomonas campestris pv. campestris. The gum gene cluster of X. oryzae encodes proteins involved in xanthan production; however, there is little experimental evidence supporting this. In this
study, biochemical analyses of xanthan produced by a defined set of X. oryzae
gum mutant strains allowed us to preliminarily assign functions to most of the gum gene products: biosynthesis of the pentasaccharide repeating unit for GumD, GumM, GumH, GumK, and GumI, xanthan polymerization
and transport for GumB, GumC, GumE, and GumJ, and modification of the pentasaccharide repeating unit for GumF, GumG, and GumL.
In addition, we found that the exopolysaccharides are essential but not specific for the virulence of X. oryzae.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Sang-Yoon Kim and Jeong-Gu Kim contributed equally to this work. 相似文献
9.
Mauricio Soto-Suárez Diana Bernal Carolina González Boris Szurek Romain Guyot Joe Tohme Valérie Verdier 《BMC microbiology》2010,10(1):170
Background
Bacterial leaf blight causes significant yield losses in rice crops throughout Asia and Africa. Although both the Asian and African strains of the pathogen, Xanthomonas oryzae pv. oryzae (Xoo), induce similar symptoms, they are nevertheless genetically different, with the African strains being more closely related to the Asian X. oryzae pv. oryzicola (Xoc). 相似文献10.
Since the identification of BRI1-Associated receptor Kinase 1 (BAK1), a member of the Somatic Embryogenesis Receptor Kinase
(SERK) family, the dual functions of BAK1 in BR signaling and innate immunity in Arabidopsis have attracted considerable attention
as clues for understanding developmental processes that must be balanced between growth and defense over the life of plants.
Here, we extended our research to study cellular functions of OsSERKs in rice. As it was difficult to identify an authentic
ortholog of AtBAK1 in rice, we generated transgenic rice in which the expression of multiple OsSERK genes, including OsBAK1, was reduced by OsBAK1 RNA interference. Resulting transgenic rice showed reduced levels of Os-BAK1 and decreased sensitivity to BL, leading to semidwarfism in overall growth. Moreover, they resulted in abnormal growth patterns,
especially in leaf development. Most of the OsBAK1RNAi transgenic rice plants were defective in the development of bulliform cells in the leaf epidermal layer. They also showed
increased expression level of pathogenesis-related gene and enhanced susceptibility to a rice blast-causing fungal pathogen,
Magnaporthe oryzae. These results indicate that OsSERK genes, such as OsBAK1, play versatile roles in rice growth and development. 相似文献
11.
Ning Xiao Yunyu Wu Zhiping Wang Yuhong Li Cunhong Pan Xiaoxiang Zhang Ling Yu Guangqing Liu Changhai Zhou Hongjuan Ji Niansheng Huang Min Jiang Zhengyuan Dai Aihong Li 《Molecular breeding : new strategies in plant improvement》2018,38(12):142
Rice blast is a serious disease caused by the filamentous ascomycetous fungus Magnaporthe oryzae. Incorporating disease resistance genes in rice varieties and characterizing the distribution of M. oryzae isolates form the foundation for enhancing rice blast resistance. In this study, the blast resistance gene Pish was observed to be differentially distributed in the genomes of rice sub-species. Specifically, Pish was present in 80.5% of Geng varieties, but in only 2.3% of Xian varieties. Moreover, Pish conferred resistance against only 23.5% of the M. oryzae isolates from the Geng-planting regions, but against up to 63.2% of the isolates from the Xian-planting regions. Thus, Pish may be an elite resistance gene for improving rice blast resistance in Xian varieties. Therefore, near-isogenic lines (NILs) with Pish and the polygene pyramid lines (PPLs) PPLPish/Pi1, PPLPish/Pi54, and PPLPish/Pi33 in the Xian background Yangdao 6 were generated using a molecular marker-assisted selection method. The results suggested that (1) Pish significantly improved rice blast resistance in Xian varieties, which exhibited considerably improved seedling and panicle blast resistance after Pish was introduced; (2) PPLs with Pish were more effective than the NILs with Pish regarding seedling and panicle blast resistance; (3) the PPL seedling and panicle blast resistance was improved by the complementary and overlapping effects of different resistance genes; and (4) the stability of NIL and PPL resistance varied under different environmental conditions, with only PPLPish/Pi54 exhibiting highly stable resistance in three natural disease nurseries (Jianyang, Jinggangshan, and Huangshan). This study provides new blast resistance germplasm resources and describes a novel molecular strategy for enhancing rice blast resistance. 相似文献
12.
Rheum grows luxuriantly in a niche of low temperature (LT) at high altitudes in Himalayan belt. The plant is expected to harbor
novel genes particularly for tolerance to LT. Using differential display, two cDNAs RaMPK1 and RaMPK2, showing homology to mitogen-activated protein kinases (MAPKs) were isolated. As compared to RaMPK1, RaMPK2 exhibited strong up-regulation in response to LT. RaMPK1 was novel in terms of possessing a small glutamine and proline rich
region at the N-terminal end. Secondly, though RaMPK1 showed homology with salicylic acid (SA) responsive MAPKs, the gene was down-regulated by SA but activated by jasmonate (JA). Abscisic acid (ABA) and polyethylene glycol (PEG) also
down-regulated RaMPK1. RaMPK2 showed down-regulation within 5 min of exposure to JA and SA treatments, followed by gradual increase in expression. Expression
of RaMPK2 was wavy in response to ABA and PEG treatment. Results are discussed in light of the novelty of these MAPKs. 相似文献
13.
Jin Yu Jiong Gao Xiao Yan Wang Qiang Wei Li Feng Yang Kai Qiu Ben Ke Kuai 《Journal of Plant Biology》2010,53(6):417-424
Probenazole (PBZ; 3-allyloxy-1,2-benzisothiazole-1,1-dioxide) is a highly effective chemical inducer of systemic-acquired
resistance (SAR). It has been used widely to protect rice plants against the rice blast fungus Magnaporthe grisea. Previous studies have shown that PBZ induces SAR through enhanced accumulation of salicylic acid (SA). Plants synthesize
SA by either a pathway that uses phenylalanine as substrate or another that involves isochorismate. To clarify how SA is produced
in PBZ-treated Arabidopsis, we examined the expression patterns and enzyme activities of phenylalanine ammonia lyase (PAL) and isochorismate synthase
(ICS), which are the main components of the phenylalanine and isochorismate pathways, respectively. PBZ exposure significantly
improved the accumulation of SA and increased ICS activity. In the sid2–2 mutant, which has a defect in ICS1, PBZ had no effect on the level of endogenous SA or activity of ICS. In contrast, PAL activity and the expression of most
PAL genes were down-regulated by such treatment in wild-type plants. These results suggest that SA is mainly synthesized via
the ICS-mediated pathway in Arabidopsis. 相似文献
14.
Astrid Ratzinger Nadine Riediger Andreas von Tiedemann Petr Karlovsky 《Journal of plant research》2009,122(5):571-579
Salicylic acid (SA) and its glucoside (SAG) were detected in xylem sap of Brassica napus by HPLC–MS. Concentrations of SA and SAG in xylem sap from the root and hypocotyl of the plant, and in extracts of shoots
above the hypocotyl, increased after infection with the vascular pathogen Verticillium longisporum. Both concentrations were correlated with disease severity assessed as the reduction in shoot length. Furthermore, SAG levels
in shoot extracts were correlated with the amount of V. longisporum DNA in the hypocotyls. Although the concentration of SAG (but not SA) in xylem sap of infected plants gradually declined
from 14 to 35 days post infection, SAG levels remained significantly higher than in uninfected plants during the whole experiment.
Jasmonic acid (JA) and abscisic acid (ABA) levels in xylem sap were not affected by infection with V. longisporum. SA and SAG extend the list of phytohormones potentially transported from root to shoot with the transpiration stream. The
physiological relevance of this transport and its contribution to the distribution of SA in plants remain to be elucidated. 相似文献
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16.
17.
Plant fungal pathogens change their cell wall components during the infection process to avoid degradation by host lytic enzymes,
and conversion of the cell wall chitin to chitosan is likely to be one infection strategy of pathogens. Thus, introduction
of chitosan-degradation activity into plants is expected to improve fungal disease resistance. Chitosanase has been found
in bacteria and fungi, but not in higher plants. Here, we demonstrate that chitosanase, Cho1, from Bacillus circulans MH-K1 has antifungal activity against the rice blast fungus Magnaporthe oryzae. Introduction of the cho1 gene conferred chitosanase activity to rice cells. Transgenic rice plants expressing Cho1 designed to be localized in the
apoplast showed increased resistance to M. oryzae accompanied by increased generation of hydrogen peroxide in the infected epidermal cells. These results strongly suggest
that chitosan exists in the enzyme-accessible surface of M. oryzae during the infection process and that the enhancement of disease resistance is attributable to the antifungal activity of
the secreted Cho1 and to increased elicitation of the host defense response. 相似文献
18.
In a glasshouse, Bemisia tabaci infestation largely reduced response of photosynthesis to irradiance and CO2 concentration of Mikania micrantha compared with the non-infested control (C) ones. The maximum irradiance-saturated photosynthetic rate (P
max) and saturation irradiance (SI) of the infested M. micrantha were only 21.3 % and 6.5 % of the C-plants, respectively. B. tabaci infestation led to the reduction of contents of chlorophyll and carotenoids in M. micrantha, which was accompanied with the decrease of actual photosystem 2 (PS2) efficiency (ΦPS2), efficiency of excitation energy capture by open PS2 reaction centres (Fv′/Fm′), electron transport rate (ETR), and photochemical quenching (qP). Moreover, superoxide dismutase and catalase activities significantly decreased while proline and glutathione contents significantly
increased in infested M. micrantha. Hence B. tabaci infestation not only induced direct damage of photosynthetic apparatus but also altered the antioxidant enzymes activities
in M. micrantha, which might as consequences accelerate senescence of this weed. 相似文献
19.
20.
Xanthomonas oryzae pv. oryzae is the pathogen that causes bacterial leaf blight in rice. Bacterial leaf blight is the main cause for severe rice underproduction
in many countries. However, with conventional methods it is difficult to quickly and reliably distinguish this pathogen from
other closely related pathogenic bacteria, especially X. oryzae pv. oryzicola, the causal organism of bacterial leaf streak in rice. We have developed a novel and highly sensitive real-time method for
the identification of this specific bacteria based on a TaqMan probe. This probe is designed to recognize the sequence of
a putative siderophore receptor gene cds specific to X. oryzae pv. oryzae, and can be identified from either a bacterial culture or naturally infected rice seeds and leaves in only 2 h. The sensitivity
of the method is 100 times higher than that of the current polymerase chain reaction (PCR) gel electrophoresis method for
diagnosis. 相似文献