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961.
Expression of RPS4 in tobacco induces an AvrRps4-independent HR that requires EDS1, SGT1 and HSP90 总被引:4,自引:0,他引:4
Zhang Y Dorey S Swiderski M Jones JD 《The Plant journal : for cell and molecular biology》2004,40(2):213-224
The Arabidopsis RPS4 gene belongs to the Toll/interleukin-1 receptor/nucleotide-binding site/leucine-rich repeat (TIR-NB-LRR) class of plant resistance (R) genes. It confers resistance to Pseudomonas syringae carrying the avirulence gene avrRps4. Transient expression of genomic RPS4 driven by the 35S promoter in tobacco leaves induces an AvrRps4-independent hypersensitive response (HR). The same phenotype is seen after expression of a full-length RPS4 cDNA. This indicates that alternative splicing of RPS4 is not involved in this HR. The extent of HR is correlated with RPS4 protein levels. Deletion analyses of RPS4 domains show the TIR domain is required for the HR phenotype. Mutations in the P-loop motif of the NB domain abolish the HR. Using virus-induced gene silencing, we found that the cell death resulting from RPS4 expression is dependent on the three plant signalling components EDS1, SGT1 and HSP90. All these data suggest that heterologous expression of an R gene can result in activation of cell death even in the absence of its cognate avirulence product, and provides a system for studying the RPS4 domains required for HR. 相似文献
962.
Doublet B Carattoli A Whichard JM White DG Baucheron S Chaslus-Dancla E Cloeckaert A 《FEMS microbiology letters》2004,236(2):301-305
Multidrug resistance plasmids carrying the bla(CMY-2) gene have been identified in Salmonella enterica serovars Typhimurium and Newport from the United States. This gene confers decreased susceptibility to ceftriaxone, and is most often found in strains with concomitant resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and tetracycline. The bla(CMY-2)-carrying plasmids studied here were shown to also carry the florfenicol resistance gene, floR, on a genetic structure previously identified in Escherichia coli plasmids in Europe. These data indicate that the use of different antimicrobial agents, including phenicols, may serve to maintain multidrug resistance plasmids on which extended-spectrum cephalosporin resistance determinants co-exist with other resistance genes in Salmonella. 相似文献
963.
Luo H Hu Q Nelson K Longo C Kausch AP Chandlee JM Wipff JK Fricker CR 《Plant cell reports》2004,22(9):645-652
Genetic transformation of creeping bentgrass mediated by Agrobacterium tumefaciens has been achieved. Embryogenic callus initiated from seeds (cv. Penn-A-4) was infected with an A. tumefaciens strain (LBA4404) harboring a super-binary vector that contained an herbicide-resistant bar gene driven either by the CaMV 35S promoter or a rice ubiquitin promoter. Plants were regenerated from 219 independent transformation events. The overall stable transformation efficiency ranged from 18% to 45%. Southern blot and genetic analysis confirmed transgene integration in the creeping bentgrass genome and normal transmission and stable expression of the transgene in the T1 generation. All independent transformation events carried one to three copies of the transgene, and a majority (60–65%) contained only a single copy of the foreign gene with no apparent rearrangements. We report here the successful use of Agrobacterium for the large-scale production of transgenic creeping bentgrass plants with a high frequency of a single-copy transgene insertion that exhibit stable inheritance patterns.Abbreviations
2,4-D:
2,4-Dichlorophenoxyacetic acid
-
bar:
Bialaphos resistance gene
-
GUS:
-Glucuronidase
-
PPT:
Phosphinothricin
-
ubi:
Ubiquitin
Communicated by J.M. Widholm 相似文献
964.
Yan CQ Qian KX Yan QS Zhang XQ Xue GP Huangfu WG Wu YF Zhao YZ Xue ZY Huang J Xu GZ Wu P 《Plant cell reports》2004,22(8):569-575
Bacterial blight is one of the major diseases affecting rice productivity. To improve the resistance of cultivated rice to bacterial blight, we introduced a bacterial blight resistance trait from Oryza meyeriana, a wild rice species, into an elite japonica rice cultivar (Dalixiang) using asymmetric somatic hybridization. One hundred and thirty-two independent lines were regenerated. The hybrid plants possessed several morphological features of the donor species, O. meyeriana. Random amplified polymorphic DNA analysis revealed that hybrid plants exhibited banding patterns derived from their parental genotypes. For the majority of the hybrids, resistance to bacterial blight pathogens was intermediate to that observed for O. meyeriana and O. sativa (cv. Dalixiang). Four of the hybrid lines exhibited a high bacterial blight resistance, but it was less than that observed for O. meyeriana. These results demonstrate that O. meyeriana can be used as a good genetic source for improving bacterial blight resistance in commercial rice cultivars through asymmetric somatic hybridization.Abbreviations
2,4-D:
2,4-Dichlorophenoxyacetic acid
-
IOA:
Iodoacetamide
-
NAA:
-Naphthaleneacetic acid
-
PEG:
Polyethylene glycol
Communicated by P. Lakshmanan 相似文献
965.
966.
967.
Photoinhibition and recovery were studied in two photosynthetic cell suspensions from soybean (Glycine max L. Merr): the wild type (WT) and the herbicide-resistant D1 mutant STR7. This mutant also showed an increase in saturated fatty acids from thylakoid lipids. STR7 was more sensitive to photoinhibition under culture conditions. In vivo photoinhibition experiments in the presence of chloramphenicol, in vitro studies in isolated thylakoid membranes, and immunoblot analysis indicated that the process of light-induced degradation of the D1 protein was not involved in the response of STR7 to light. At growth temperature (24°C), the recovery rate of photoinhibited photosystem II (PSII) was slower in STR7 relative to WT. Photoinhibition and recovery were differentially affected by temperature in both cell lines. The rates of photoinhibition were faster in STR7 at any temperature below 27°C. The rates of PSII recovery from STR7 were more severely affected than those of WT at temperatures lower than 24°C. The photoinhibition and recovery rates of WT at 17°C mimicked those of STR7 at 24°C. In organelle translation studies indicated that synthesis and elongation of D1 were substantially similar in both cell lines. However, sucrose gradient fractionation of chloroplast membranes demonstrated that D1 and also other PSII proteins such as D2, OEE33, and LCHII had a reduced capability to incorporate into PSII to yield a mature assembled complex in STR7. This effect may become the rate-limiting step during the recovery of photoinhibited PSII and may explain the increased sensitivity to high light found in STR7. Our data may hint at a possible role of fatty acids from membrane lipids in the assembly and dynamics of PSII.Abbreviations DCBQ 2,6-Dichloro p-benzoquinone - DM Dodecyl--d-maltoside - DTT Dithiothreitol - HL High light - LHCII Light-harvesting complex II - LL Low light - OEE Oxygen-evolving extrinsic proteins - PAGE Polyacrylamide gel electrophoresis - PG Phosphatidylglycerol - PSII Photosystem II - QA and QB Secondary quinone electron acceptors from PSII - RC Reaction center - SDS Sodium dodecyl sulfate - WT Wild type 相似文献
968.
Paraquat resistance of transgenic tobacco plants over-expressing the Ochrobactrum anthropi
pqrA gene
Transgenic tobacco plants over-expressing the Ochrobactrum anthropi pqrA gene, which encodes a membrane transporter mediating resistance to paraquat, were generated. Transgenic plants displayed higher resistance against paraquat than wild-type plants, as estimated by plant viability, ion leakage and chlorophyll loss, but no resistance against other active oxygen generators, such as H2O2 and menadione. Moreover, lower levels of paraquat accumulated in transgenic plants, compared to wild-type plants, indicating that the PqrA protein detoxifies paraquat either via increased efflux or decreased uptake of the herbicide, but not by removing active oxygen species. The results collectively demonstrate that the bacterial paraquat resistance gene, pqrA, can be functionally expressed in plant cells, and utilized for the development of paraquat-resistant crop plants. 相似文献
969.
Nemat?M.?HassanEmail author Mamdouh?S.?Serag Fawzia?M.?El-Feky 《Acta Physiologiae Plantarum》2004,26(2):165-175
Mung bean and tomato were in vitro selected on media containing 0, 25, 50, 100 and 150 mM NaCl. Two types of media (hormone supplemented media, CB and hormone
free media, MS) were used for mung bean using cotyledon explants whereas two types of explants (cotyledons and shoot apices)
were used for tomato on MS media. Total-N, protein content, nitrite reductase (NiR) activity and protein protein profiles
were checked in selected plants and compared to original non selected ones. NaCl at low concentrations slightly increased
total-N in shoots and roots of in vitro selected mung bean and tomato whereas higher concentrations induced significant reductions. Similar increases in protein
content were detected at lower concentrations with no significant effects thereover. On the contrary, NaCl gradually inhibited
NiR activity. Similar responses of total-N, protein and NiR activity, but with greater magnitudes, were detected in original
plants. In addition, NaCl significantly reduced dry weights of shoots and roots of either in vitro selected or, in particular, original intact plants. Moreover, electrophoresis (SDS-PAGE) of protein from shoots of either
in vitro selected or intact plants showed that NaCl induced new protein bands while some others were concomitantly disappeared. The
induction of one or more of the 86.4, 79, 77.6, 77 and 71.5 kDa bands following in vitro selection and/or the disappearance of the 86 kDa band from intact plants seemed necessary for mung bean resistance. Also,
the presence of 86.2 kDa band and/or the loss of the 85.8 and 57.5 kDa bands might be included in tomato resistance. Of these
induced bands in mung bean selected on CB media, only two bands were detected in plants selected on MS media. In tomato, two
bands lost following selection from cotyledons but only one band lost following selection from shoot apices. These changes
in protein pattern therefore might serve as adaptive regulators for resistance to NaCl. 相似文献
970.
Lopez C Jorge V Piégu B Mba C Cortes D Restrepo S Soto M Laudié M Berger C Cooke R Delseny M Tohme J Verdier V 《Plant molecular biology》2004,56(4):541-554
Two economically important characters, starch content and cassava bacterial blight resistance, were targeted to generate a large collection of cassava ESTs. Two libraries were constructed from cassava root tissues of varieties with high and low starch contents. Other libraries were constructed from plant tissues challenged by the pathogen Xanthomonas axonopodis pv.manihotis. We report here the single pass sequencing of 11 954 cDNA clones from the 5’ ends, including 111 from the 3’ ends. Cluster analysis permitted the identification of a unigene set of 5700 sequences. Sequence analyses permitted the assignment of a putative functional category for 37% of sequences whereas ~ 16% sequences did not show any significant similarity with other proteins present in the database and therefore can be considered as cassava specific genes. A group of genes belonging to a large multigene family was identified. We characterize a set of genes detected only in infected libraries putatively involved in the defense response to pathogen infection. By comparing two libraries obtained from cultivars contrasting in their starch content a group of genes associated to starch biosynthesis and differentially expressed was identified. This is the first large cassava EST resource developed today and publicly available thus making a significant contribution to genomic knowledge of cassava. 相似文献