scholarly journals Identificação de potenciais plantas hospedeiras alternativas de Xanthomonas campestris pv. viticola

2014 ◽  
Vol 44 (4) ◽  
pp. 595-598
Author(s):  
Morgana Mateus Santos ◽  
Ana Rosa Peixoto ◽  
Esmailly de Sousa Pessoa ◽  
Marco Aurélio Gama ◽  
Rosa de Lima Ramos Mariano ◽  
...  

Este estudo teve como objetivo identificar possíveis hospedeiras alternativas de Xanthomonas campestris pv. viticola (Xcv), visando a fornecer subsídios para o manejo do cancro bacteriano da videira. Vinte e seis espécies vegetais foram inoculadas artificialmente com o isolado Xcv3 e mantidas em condições de casa de vegetação, sendo avaliada a evolução sintomatológica da doença, como manchas necróticas angulares e lesões nas nervuras. O Xcv3 foi reisolado a partir de cada hospedeiro alternativo com sintomas, sendo identificado por PCR (Polymerase Chain Reaction), com iniciadores específicos. As espécies inoculadas que apresentaram os sintomas típicos da doença foram Glycine sp., Senna obtusifolia, Desmodium discolor, Amaranthus deflexus, Azadirachta indica, Solanum lycopersicum e Vigna unguiculata. As espécies da família Poaceae, Bidens pilosa, Emilia fosbergii, Praxelis pauciflora, Macroptilium lathyroides e Portulaca oleracea não apresentaram sintomas durante o período da avaliação.

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Melanie L. Lewis Ivey ◽  
Geoffrey Tusiime ◽  
Sally A. Miller

Polymerase chain reaction (PCR) primers (BXW-1 and BXW-3) for conventional PCR were developed from conserved sequences in the hrpB operon of the hrp gene cluster from Xanthomonas campestris pv. musacearum, the causative agent of banana Xanthomonas wilt (BXW). All 50 strains of X. campestris pv. musacearum, isolated from Uganda, Rwanda, and Tanzania, produced a 214-bp amplicon when whole cells, bacterial ooze from infected tissue, and genomic DNA purified from bacterial ooze or infected tissue were used as template. The BXW primers also detected strains of X. axonopodis pv. vasculorum isolated from sugarcane and maize and strains of X. vasicola pv. holcicola isolated from sorghum. All of the strains of X. campestris pv. musacearum were clonal when compared using enterobacterial repetitive intergenic consensus PCR.


2009 ◽  
Vol 22 (3) ◽  
pp. 321-329 ◽  
Author(s):  
Dong-Liang Huang ◽  
Dong-Jie Tang ◽  
Qing Liao ◽  
Xiao-Qian Li ◽  
Yong-Qiang He ◽  
...  

In bacteria, Zur is a key regulator for zinc homeostasis. Our previous work has shown that, in the phytopathogen Xanthomonas campestris pv. campestris, in addition to regulating zinc homeostasis, Zur is essential for full virulence. Here, we demonstrate that the X. campestris pv. campestris Zur is involved in hypersensitive response (HR) and positively regulates the transcription of hrpA to hrpF operons and hrpX but not hrpG. Constitutively expressing hrpX but not hrpG in the zur mutant could bypass the requirement of Zur for the expression of hrpA to hrpF operons and the induction of wild-type HR, indicating that Zur controls the expression of hrp cluster via hrpX. Promoter-gusA reporter and semiquantitative reverse-transcription polymerase chain reaction analyses revealed that HrpG controls the expression of hrpX and HrpX regulates the expression of all the six hrp operons (hrpA to hrpF) in X. campestris pv. campestris.


Author(s):  
G. W. Hacker ◽  
I. Zehbe ◽  
J. Hainfeld ◽  
A.-H. Graf ◽  
C. Hauser-Kronberger ◽  
...  

In situ hybridization (ISH) with biotin-labeled probes is increasingly used in histology, histopathology and molecular biology, to detect genetic nucleic acid sequences of interest, such as viruses, genetic alterations and peptide-/protein-encoding messenger RNA (mRNA). In situ polymerase chain reaction (PCR) (PCR in situ hybridization = PISH) and the new in situ self-sustained sequence replication-based amplification (3SR) method even allow the detection of single copies of DNA or RNA in cytological and histological material. However, there is a number of considerable problems with the in situ PCR methods available today: False positives due to mis-priming of DNA breakdown products contained in several types of cells causing non-specific incorporation of label in direct methods, and re-diffusion artefacts of amplicons into previously negative cells have been observed. To avoid these problems, super-sensitive ISH procedures can be used, and it is well known that the sensitivity and outcome of these methods partially depend on the detection system used.


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