Daniela Bravo¹, Paola Fory¹, Girlena Aricapa¹, Gustavo Prado¹, Edgar Torres², and Gloria Mosquera¹
¹Rice Pathology, ²Rice Breeding
International Center for Tropical Agriculture (CIAT). Kilometro 17 Recta Cali‐Palmira
Contact: g.m.mosquera@cgiar.org
INTRODUCTION
• Pathogenicity assays are showing that pigmented colonies of the
The panicle blight, caused by B. glumae, reported in countries bacterium are more aggressive than non pigmented ones. It also
throughout the world causes losses in rice fields that can reach up to
world,
65% as it directly affects grain filling (Lai et al. 1999). For the first time has been observed that there are differences in aggressiveness
the bacteria was reported in Latin America in 1989 (Zeigler and among pigmented strains (Figure 3B).
Alvarez), but in Colombia was just until 2007 it became an
economically important disease causing production losses up to 30% Evaluation of strain genetic variability
in Cordoba (Correa et al , 2007). So far potential sources of resistance
in the host , virulence mechanisms or variability of the pathogen to
facilitate the development of an effective tool to control the disease M 1 2 3 4 5 6 7 8 9 10
are unknown. Therefore analysis of pathogenicity and genetic
variability of Colombian population of B. glumae is essential for
establishing germplasm evaluation to define potential sources of
tolerance that could be used in breeding programs as a tool to control
the disease
disease.
A
Evaluation of strain aggressiveness
120
100
age %
80
60
Dama
40
Figure1. Colombian locations from where B. glumae was isolated 20
0 B
MATERIALS AND METHODS 1 2 3 4 5 6 7 8 9 10
Inoculated strains
• Establishment of the first collection of B. glumae, consisting of 106
isolations from Colombian regions affected by the pathogen (Figure Figure3. The BOX‐PCR and pathogenicity test in A and B, respectively. Lanes
1). 1 to 10 are different strains of B. glumae; lane 6 is a non‐pigmented strain
• Pathogenicity test of a subset of 39 strains of B glumae has been
B.
done by inoculating ColXXI rice cultivar in flowering stage. CONCLUSIONS
• Strain pathogenicity was measured on inoculated panicles 14 days
after inoculation, as percentage of affected grains over the total • In 2007 B. glumae was reported for the first time in Monteria
(Figure2). Cordoba, nowadays we have isolated the bacteria in 9 departments
• Molecular characterization of the same strains is being assessed by of Colombia This indicates that the disease has been spread
Colombia.
using BOX‐PCR, ERIC‐PCR and REP‐PCR techniques. throughout rice‐growing areas of the country in recent years.
• Based on preliminary results, strains of B. glumae are different in
aggressiveness as well as genetic composition.
• This strategy will enable us to choose a group of isolates
representing th genetic variability and pathogenicity of th
ti the ti i bilit d th i it f the
bacteria population in Colombia, which may be used in subsequent
studies to evaluate rice cultivars looking for tolerance sources.
• This will be a big contribution to the improvement programs aimed
to control the panicle blight caused by B. glumae by means of the
Figure2. B. glumae infecting ColXXI panicles.
Figure2. B. glumae infecting ColXXI use of disease‐tolerant varieties.
REFERENCES
RESULTS AND DISCUSSION
• Correa, F., Pérez, C.R., Saavedra, E. Añublo bacterial de
, , , , ,
• A group of 39 strains were chosen b d on of th i variety of
f t i h based f their i t f
la panicula del arroz. 2007. ARROZ. 57:468.
isolation and geographical origin in order to cover as much as
• LaiI, X.H., A.M. Mcclung, & M.A. MarchettiI. 1999. The effects of
possible the potential variability present in the whole collection.
panicle blight of rice on grain weight and viability. Agricultural.
Research Service, Tektran,Texas. USDA: Abstract
• BOX‐PCR technique was standardized and displayed a well‐defined
• Zeigler R S Alvarez E 1989 Pant Disease 73:368
Zeigler, R.S., Alvarez, E. 1989. 73:368.
band pattern (Figure 3A), differentiating isolations of B. glumae.
FUNDING MADR 2007B7614‐203