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STUDIES ON THE ROLE OF HEAT SHOCK TRANSCRIPTION FACTORS AND PROTEINS ON HIGH TEMPERATURE TOLERANCE IN WHEAT GENOTYPES (Triticum aestivum L.)

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Title STUDIES ON THE ROLE OF HEAT SHOCK TRANSCRIPTION FACTORS AND PROTEINS ON HIGH TEMPERATURE TOLERANCE IN WHEAT GENOTYPES (Triticum aestivum L.)
 
Creator KRISHNA KUMAR G
 
Contributor R.K. Sairam
 
Subject ---
 
Description T-8514
India is the second largest producer of wheat in the world. High temperature spells
towards the end of the crop season are a major determinant of wheat yield, especially under
Indian conditions. The present study was conducted with three contrasting wheat genotypes
in terms of temperature tolerance viz. Halna, DBW 14 and HD 2687 sown on 25th November,
15th December and 10th January of 2010-11. The observations were taken at 30 days after
sowing, booting, anthesis and 10 days after anthesis. Late sowing induced high temperature
stress led to the reduction in relative water content (RWC), membrane stability index (MSI),
chlorophyll content, carotenoid content and photosynthetic rate in all the varieties. The
reduction was higher at anthesis and 10 days after anthesis, when compared to 30 days after
sowing and booting. Comparatively higher reductions were observed in susceptible genotype,
HD 2687 compared to Halna and DBW 14. High temperature stress induced oxidative stress,
measured in terms of lipid peroxidation was found to be significantly higher under high
temperature stress treatment especially more so in HD 2687. Crop duration, plant height,
plant biomass, number of tillers, number of ears per plant and grain weight per panicle were
also negatively affected by high temperature stress. The tolerant genotypes Halna and DBW
14 maintained comparatively high grain weight per ear, 1000 grain wt and grain yield per
plant, under high temperature stress. Biochemical analysis of grains revealed that high
temperature stress treatment led to significant reduction in starch content and increase in
soluble sugar and grain protein content. However, Halna maintained optimal level of starch
with little temperature induced increase in soluble sugars and grain protein in comparison
with other genotypes. Expression analysis of heat shock transcription factors revealed that
tolerant genotypes Halna and DBW 14 were having higher levels of heat stress induced
expression of heat shock transcription factors HSFA2b, HSFA4a and HSF8. Halna and DBW
14 also maintained higher levels of expression of small heat shock protein (sHSP) like 17.3,
16.9B and high molecular weight HSP70, HSP80 and HSP101C. Sequence comparison of
HSPs and HSFs revealed the homology of nucleotide sequences between Triticum aestivum,
Oryza sativa, Hordeum vulgare and Arabidopsis thaliana, indicating the conservation of
nucleotide sequences of HSPs and HSFs across genera. The amino acid sequences deduced
from the nucleotide sequences also showed significant sequence homology across genera.
From the study, it can be concluded that the efficient up-regulation of HSFs and HSPs played
a major role in imparting high temperature stress tolerance in wheat.
 
Date 2016-12-01T11:15:17Z
2016-12-01T11:15:17Z
2011
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/88560
 
Format application/pdf
 
Publisher IARI, DIVISION OF PLANT PHYSIOLOGY