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NFLUENCE OF TEMPERATURE RISE ON RICE BLAST RESISTANCE CONFERRED BY R GENE

KrishiKosh

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Title NFLUENCE OF TEMPERATURE RISE ON RICE BLAST RESISTANCE CONFERRED BY R GENE
 
Creator P. MADHUSUDHAN
 
Contributor Parimal Sinha
 
Subject null
 
Description t-9787
Temperature rise due to climate change is reported to alter host-pathogen interaction.
In the present study, differential response of R gene for blast resistance (Pi54) against
the pathogen under different temperatures have been documented. The temperature
modulation on leaf blast resistance based on host-pathogen interaction has been
considered on a population of near-isogenic line for resistance gene (Pi54) and alone
avirulent isolate of the pathogen. For the near isogenic line possessing R gene,
relative resistance for infection efficiency (RRIE) and sporulation (RRSP) with
reference to susceptible recurrent parent is found to be higher at suboptimal (22°C)
and supra-optimal (32°C) temperature as compared to optimal (27°C) temperature for
infection. Irrespective of resistance higher pathogen growth or lesion development
rate was noted at 27°C. Combined relative resistance (RRc) is calculated on RRIE and
RRSP; it indicated a pattern of a convex parabola and appeared to be a mirror image
of the pathogen’s infection ability.Variation in resistance pattern is the reflection of
pathogen’s sensitivity to temperature rather than the effect of resistance. Thus, higher
performance of resistance at suboptimal and supra-optimal temperature is attributed to
lower level of pathogen growth or lesion development. Blast simulation based on
RRIE and RRSP has indicated that the components of resistance are effective to
combat leaf blast infection at suboptimal as compared to optimal temperature for
infection.
Based on experimental data of temporal expression i.e., WRKY45, Pi54 and
phosphorylation in response to leaf blast infection, the relative resistance has been
justified.Transcription factor (WRKY45) and resistance gene (Pi54) expression
dynamics has indicated that they are co-transcribed during infection process. Higher
level of activation coefficient and binding occupancy at 22°C lead to higher
transcription level for Pi54 than at 27° and 32°C. Minimum level of activation
coefficient and binding occupancy at 32°C lead to low transcription level for Pi54.
Therefore, at 22°C (suboptimal) higher level of resistance against leaf blast is
associated with increased expression of WRKY45/Pi54 gene and higher level of
phosphorylation, while at 27°C, their expressions is lower or inhibited. At
27°C,probably due to faster growth of the pathogen activation of Pi54 gene is
hindered or may be partly host phosphorylated products are utilized for pathogen
growth. As the pathogen is hemibiotroph its faster growth and toxin production ability
might have disturbed transcription and translation machineries in the
host.Comparatively slower infection process or otherwise longer infection time at
22°C has enough time for induction of Pi54 gene ascompared to 27°C, whereas, faster
infection process disrupts the induction as well as expression of Pi 54 gene. At 32°C
(supra-optimal) slower infection process is associated with low induction of
transcription/phosphorylation. However, higher combine relative resistance (RRc) at
surpa-optimal temperature is more of low infection ability not because of stronger
defence reaction.R gene regulation appeared too induced by pathogen infection
although otherwise it is constitute expression. Role of transcription factor has been
associated with regulation R gene expression.
To sum up, temperature influence on expression of R gene (Pi54) in rice is
dependent on the host-pathogen interaction rather than R gene alone. Therefore,
temperature rise impact on resistance gene indirectly can be estimated based on the
pathogen response to temperature.Pathogen response in relation resistance is dynamic
process as temperature regime is variable in time and location. Hence, evaluation of
resistance components in relation to temperature can be useful for future breeding
programmes as resistance performance can be predicted using epidemiological
modeling. Greater use of environmental data from field experiments could help to
identify varieties from breeding programmes which appeared to be more resilient to
temperature changes. Therefore, in relation to temperature, resistance components for
epidemic check may be identified for future breeding programmes
 
Date 2018-10-09T09:53:46Z
2018-10-09T09:53:46Z
2017
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/5810078133
 
Language en_US
 
Format application/pdf
 
Publisher DIVISION OF PLANT PATHOLOGY ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI