BIOCHEMICAL AND PHYSIOLOGICAL ANALYSIS AND PROTEIN PROFILING IN WHEAT {Triticum aestivum L.) GENOTYPES UNDER HEAT STRESS 1939
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Date
2014-10
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JAU, JUNAGADH
Abstract
The present experiment on "Biochemical and Physiological Analysis and
Protein Profiling in Wheat {Triticum aestivum L.) Genotypes under Heat Stress" was
conducted at Department of Biotechnology, Junagadh Agricultural University,
Junagadh. The experiment-1 was carried out using fourteen wheat genotypes and four
heat treatments using Factorial CRD design, where seeds were grown in germination
bag filled with soil for 10 days. The seedlings were subjected to control and heat
treatments at 35°C, 40°C and 45°C for four hour and samples were analysed for
relative water content, membrane stability and injury, lipid peroxidation, hydrogen
peroxide content and chlorophyll stability index. Heat tolerant genotype GW-190
genotype showed highest membrane stability and relative water content and lowest
membrane injury, lipid peroxidation and hydrogen peroxide compared to other
genotype so it was selected as best heat tolerant genotype. Heat susceptible genotype
J-2010-11 showed lowest membrane stability (MS) and relative water content and
highest membrane injury, lipid peroxidation and hydrogen peroxide content so it was
selected as highly susceptible genotype. Above physiological and biochemical
parameters may be used for screening the susceptible and tolerant wheat genotypes
against heat stress. H2O2 and MS are more effective indicators for screening heat
tolerant genotypes under stress condition.
From results of the experiment-1, one heat tolerant (GW-190) and heat
susceptible (J-2010-11) wheat genotypes were selected and the plants were subjected
to two groups; control and heat treatments where 40°C and 45°C heat treatments
given for 2 h and 4 h of duration and physiological, biochemical, antioxidant enzyme
activities, Isoenzymes and Protein profiling by 2D electrophoresis analysis were
performed. Relative water content and membrane stability were found to be higher in
heat tolerant genotype GW-190 compared to heat susceptible genotype J-2010-11 at
tillering and grain filling stages. As heat stress and duration of heat stress increased
the relative water content and membrane stability of heat tolerant and heat susceptible
genotypes were decreased at both the stages of wheat development. Compared to
tillering stage, relative water content and membrane stability were found lower in
grain filling stage because of increased temperature. Protein, Proline and glycine
betaine, Glutathione reductase, Peroxidase and Superoxide dismutase acitivities were
found to be higher in heat tolerant genotype GW-190 compared to heat susceptible
genotype J-2010-11 at tillering and grain filling stages. As heat stress and duration of
heat stress increased, the biochemical constitutes and antioxidant enzymes activities
of heat tolerant and heat susceptible genotypes also increased at both the stages of
wheat development. As well all the biochemical constitutes and all three antioxidant
enzymes activities were found to be higher in tillering stage compared to grain filling
stage. At tillering stage, in case of Peroxidase, band No. 5 (Rm= 0.289) and band No.
6 (Rm=0.495) were present only in heat tolerant genotype while it was absent in heat
susceptible genotype. At grain filling stage, band No. 3 (Rm=0.160) was present only
in heat tolerant genotype. In case of Superoxide dismutase at tillering stage all the
bands were present in heat tolerant as well in heat susceptible genotypes. At graing
filling stage, band No. 2 (Rm—0.072) was present only in heat tolerant genotype. So
isoenzymes may be useful for screening the heat tolerant and heat susceptible
genotypes.
At tillering stage, more total protein spots (1207) were recorded compared to
that of (972) spots at grain filling stage. Compared to control, in heat stress condition
expression of spots were increased. This was not true for grain filling stage. At
tillering stage, highest numbers of protein spots (207) were found at 45°C for 4h
duration in heat tolerant genotype GW-190 while it was true (148) spots at 40°C for
2h duration in heat tolerant genotype GW-190 at grain filling stage. The protein spots
showed the differential expression pattern in treated heat tolerant genotype might be
responsible for the stronger heat tolerance.
Scanning electron microscopy of wheat leaves showed that analysis of variance
indicated significant differences for stomatal length existed among heat tolerant and
susceptible genotype as well significant differences were found for stomatal width
among heat tolerant and susceptible genotype. Total 12 Operon series RAPD primers
were amplified to generate the 105 fragments. The percent polymorphism obtained
for RAPD primers were ranged from 71.4% to 100% with an average value of
92.33% per primer. Subcluster A1 (b) of cluster-1 consisted of only one heat tolerant
genotype J-2010-06 with more than 66% of similarity. Subcluster A2 of cluster-I
consisted of only one heat susceptible genotype J-2010-13 similarity of more than
85%. Cluster-II consisted of two genotypes J-2010-05 and GW-190 sh "
similarity of more than 85% that belongs to heat tolerant groups. These primers
be used to screen the genotypes against heat stress.
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BIOTECHNOLOGY