| |
|
|
| |
|
|
Research  |
|
|
|
| |
| |
Retrotransposon‐mediated mutation of rice blast resistance gene Pi-b.
|
|
|
|
|
|
| |
|
 Authours
|
Nam-Soo Jwa[0][*] and Yong-Hwan Lee[1] |
| Title |
Retrotransposon‐mediated mutation of rice blast resistance gene Pi-b. |
| Journal |
The Plant Pathology Journal, 2001 (17) ~ |
Abstract
|
Plants may have evolved a system of disease resistance to
variety of pathogens through a long period of coevolution
with a wide array of microorganisms. The resistance is
determined by the role of interaction between resistance (R)
genes in the host and complementary avirulence (AVR)
genes in the pathogen. These gene-for-gene interactions
had been proposed by Flor (1956), and have been observed
from the interactions between plants and a wide range of
pathogens such as fungi, bacteria, viruses, nematodes and
insects (Curte, 1986). First AVR gene had been identified by
Staskawicz et al. (1984), which was isolated from Psuedomonas
syringae pv. glycinea. The AVR gene successfully
transformed susceptible soybean cultivars into their genome
and they became avirulent. Importance of the genetic basis
of plant R gene had been paid attention early by plant
breeders who first recognized the entity of disease resistance
genes, and they were often inherited by Mendelian
way. Since the first R gene PTO had been cloned (Martin et
al., 1993), the molecular basis of the resistance mechanism
has been extensively studied for the development of a novel
strategy for disease resistance.
Breeding for resistant varieties has been a major tool for
controlling this disease (Bonman, 1992). However, frequent
breakdown of resistance has been reported relatively
short after the resistant cultivars released in the field (Kiyosawa,
1982). Much effort has been conducted to understand
the mechanisms responsible for breakdown of
resistance. The phenomenon of resistance-breakdown to
date has been mostly explained by genetical changes in the
fungal pathogens through heterokaryosis (Suzuki, 1965),
parasexual recombination (Genovesi and Magill, 1976),
and aneuploid (Kameswar Row et al., 1985). More recently,
unstability of avirulence (AVR) genes of the fungal pathogen
such as AVR-Pita, AVR1-TSUY and PWL2 was suggested
as an important factor in virulence changes at the
molecular level (Valent and Chumley, 1994). It was also
reported that M. grisea race containing AVR-Pita gained
virulence through mutations including deletions, point
mutation and insertion of Pot3 in the AVR gene (Valent and
Chumley, 1994). However, the precise mechanism of resistance-
breakdown in rice against fungal infections remains
to be elucidated. Although several potential mechanisms
for new race appearance have been proposed, little information
is available on the mechanisms of resistance-breakdown
in the plant. |
Link
|
 |
|
|
| |
|
|
|
|
| |
|
|
|
|
