Need for flagella for complete virulence of Pseudomonas syringae pv. tabaci: genetic analysis with flagella-defective mutants ?fliC and ?fliD in host tobacco plants     

Yuki Ichinose  Rena Shimizu  Yoko Ikeda  Fumiko Taguchi  Mizuri Marutani  Takafumi Mukaihara  Yoshishige Inagaki  Kazuhiro Toyoda  Tomonori Shiraishi 《Journal of General Plant Pathology》2003,69(4):244-249

The flagellins purified from Pseudomonas syringae pv. tabaci induce a hypersensitive reaction in nonhost tomato cells. To investigate the role of flagella and flagellin in the compatible interaction, we generated two types of flagella-defective mutant. The fliC mutant lost the fliC gene that encodes flagellin protein, whereas the fliD mutant lost the fliD gene that encodes HAP2-capping protein. The two mutants had markedly reduced ability to cause disease symptoms in tobacco leaves. Furthermore, propagation of the mutants in tobacco leaves was less than that in wild-type pv. tabaci. Compared to the inoculation with wild-type pv. tabaci, inoculation with the two mutants did not markedly induce the expression of typical defense response-related genes such as PAL and hsr203J. Complementation of each fliC and fliD gene to the corresponding deficient mutant restored motility and virulence. These results indicate that flagella of P. syringae pv. tabaci are indispensable organelles for complete virulence on host tobacco plants.  相似文献   

Novel PCR primers for detection of genetically diverse virulent <Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis> biovar 1 strains     

Lani E. Yakabe  M. Malendia Maccree  Padma Sudarshana  Ali E. McClean  Shane R. Parker  William P. Wechter  Gernot Presting  Mizuri Marutani-Hert  Daniel A. Kluepfel 《Journal of General Plant Pathology》2012,78(2):121-126

Novel PCR primers were developed to amplify a 243-bp fragment of an intergenic region between gene 5 and tms2 on the T-DNA of Agrobacterium tumefaciens biovar 1. These primers exhibit 100% positive correlation with strain virulence, 100% negative correlation with avirulence, and did not generate extraneous bands, thus facilitating robust real-time PCR detection.  相似文献   

Flagellin from Pseudomonas syringae pv. tabaci induced hrp-independent HR in tomato     

Mizuri Marutani  Fumiko Taguchi  Rena Shimizu  Yoshishige Inagaki  Kazuhiro Toyoda  Tomonori Shiraishi  Yuki Ichinose 《Journal of General Plant Pathology》2005,71(4):289-295

We have previously shown that flagellin of Pseudomonas syringae pv. tabaci is an elicitor that induces a hypersensitive reaction (HR) in nonhost tomato cells. Flagellin is the major HR elicitor produced by this pathogen, as shown by the inability of a flagellin-defective mutant, ΔfliC, to induce HR. Also, a ΔfliD mutant that secretes large amounts of monomer flagellins induces a strong HR in tomato. In this study, the possible involvement of an Hrp type III secretion system (TTSS) in flagellin-induced HR was investigated using flagella-defective mutants or Hrp TTSS-defective mutants. The hrcC gene encodes HrcC protein, which is required for Hrp pilus formation in the outer membrane. An hrcC mutation, introduced into the wild-type, ΔfliC, and ΔfliD mutants of P. syringae pv. tabaci did not affect swimming motility or flagellin secretion, whereas all ΔhrcC, ΔfliC, and ΔfliD mutants lost the ability to cause disease on host tobacco leaves. However, the ΔhrcC mutant and the ΔfliD/ΔhrcC double mutant were still able to induce HR cell death, expression of one of the defense-related genes hsr203J, and the generation of hydrogen peroxide in nonhost tomato cells. Thus, flagellin is required for both pathogenicity in host tobacco and HR in nonhost tomato. On the other hand, hrp TTSS is necessary for pathogenicity on host tobacco but is not indispensable to induce HR in nonhost tomato. These results clearly show that flagellin-induced HR is hrp-independent in tomato.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number AB049570  相似文献   

Effect of fluvial and geomorphic disturbances on habitat segregation of tree species in a sedimentation-dominated riparian forest in warm-temperate mountainous region in southern Japan     

Hiroka Ito  Satoshi Ito  Tamotsu Matsui  Tomomi Marutani 《Journal of Forest Research》2006,11(6):405-417

We investigated habitat segregation and patterns of species diversity of trees in relation to variations in fluvial and geomorphic disturbances (erosion or sedimentation) along a longitudinal stream gradient from V-shaped valley to alluvial fan and between valley and adjacent hill slopes in a warm-temperate mountainous riparian forest in Kyushu, southwestern Japan. We longitudinally divided the riparian area into four geomorphic zones: V-shaped valley (VV-zone), upper fan (UF-zone), middle fan (MF-zone), and lower fan (LF-zone). We surveyed the distribution of tree species (diameter at breast height ≥3 cm) in the four riparian zones and in additional plots on hill slopes (SL-zone) representing the broader, nonriparian forest matrix. Detrended correspondence analysis ordination demonstrated variations in species composition along the longitudinal stream gradient. Species guild analysis based on the detection of the species preferred zone by a bootstrap method revealed a guild structure corresponding to each geomorphic zone. The four riparian zones were differentiated from the SL-zone by having a low proportion of SL-guild species and a high proportion of infrequent species that were characterized by deciduous leaf habit. The LF-zone was the most differentiated and was characterized by low tree density and specialist species established on the flat and unstable soil surface created by frequent deposition of sediment. The UF- and MF-zones were characterized by a high tree density and species richness (particularly of infrequent species) established on the stable ground surface of a high alluvial terrace. Microsite heterogeneity produced by channel formation may also maintain a high species diversity in the riparian zones.  相似文献