18 research outputs found
Genetic Analysis and Molecular Identification of Virulence in Xanthomonas oryzaepv.oryzaeIsolates
Bacterial leaf blight (BLB) of rice is a very destructive disease worldwide and is caused byXanthomonas oryzaepv.oryzae(Xoo).The
aimofthepresentstudywastoexamineiftheXoovirulence pathotypes obtained using phenotypic pathotyping could be confirmed
using molecular approach. After screening of 60 Operon primers with genomic DNA of twoXooisolates (virulent pathotype,Vr,
and mildly virulent pathotype,MVr), 12 Operon primers that gave reproducible and useful genetic information were selected and
used to analyze 50Xooisolates from 7 West African countries. Genetic analysis revealed two majorXoovirulence genotypes (Mta
andMtb)withMtahaving two subgroups (Mta1andMta2).Mta1(Vr1) subgroup genotype has occurrence in six countries and
Mta2(Vr2) in three countries whileMtbgenotype characterized mildly virulence (MVr)Xooisolates present in five countries.
The study revealed possible linkage and correlation between phenotypic pathotyping and molecular typing ofXoovirulence.Xoo
virulence genotypes were known to exist within country and there was evidence ofXoopathogen migration between countries.
Durable resistance rice cultivars would need to overcome bothMtaandMtb Xoovirulence genotypes in order to survive after their
deployment into different rice ecologies in West Africa
Two genotypes of Xanthomonas oryzae pv. oryzae virulence identified in West Africa
Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo), is a very destructive rice
disease worldwide. The aim of the present study was to examine if the Xoo virulence pathotypes
obtained using phenotypic pathotyping could be confirmed using molecular approach. After screening
of 60 Operon primers with genomic DNA of two Xoo isolates (virulent pathotype, Vr and mildly virulent
pathotype, MVr), 12 Operon primers that gave reproducible and useful genetic information were
selected and used to analyze 50 Xoo isolates from 7 West African countries. Genetic analysis revealed
two major Xoo virulence molecular type (Mt) which were Mta and Mtb with Mta having two subgroups
(Mta1 and Mta2). Mta1 (Vr1) subgroup genotype has occurrence in six countries and Mta2 (Vr2) in three
countries while Mtb genotype characterized mildly virulence (MVr) Xoo isolates present in five
countries. The study revealed possible linkage and correlation between phenotypic pathotyping and
molecular typing of Xoo virulence. Durable resistance rice cultivars would need to overcome both Mta
and Mtb Xoo virulence genotypes in order to survive after their deployment into different rice ecologies
in West Africa