GENETIC VARIABILITY AND RELEVANCE OF EPICUTICULAR WAXES IN RICE: PHYSIOLOGICAL CHARACTERIZATION AND DIFFERENTIAL EXPRESSION OF A FEW WAX BIOSYNTHETIC GENES LEADING TO ALLELE MINING
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Date
02-08-12
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University of Agricultural Sciences GKVK, Bangalore
Abstract
Maintaince of positive turgor and positive carbon gain are most
critical for achieving increased water productivity. Plants have evolved to
accumulate waxes on the leaf surfaces as a strategy to conserve moisture by
reducing non stomatal transpiration. Further through reflection of heat
radiations waxes decreases leaf temperature there by evolving an optimistic
strategy for water conservation.
To examine these hypotheses a set of 86 diverse germplasm of rice
were evaluated for epicuticular wax content which ranged between 1μg to
25μg/cm2 leaf area representing a significant variability. This variability
was consistent across developmental stages and seasons indicating a strong
genetic control of this trait. EWC was found to have negative relationship
between both rate of water loss and leaf temperature reiterating the relevance
of waxes. The increased wax content among the stressed plants indicate the
adoptive relevance of waxes.
Based on the previous experiments, four genotypes each for low and
high wax categories were selected and raised under well watered and water
limited conditions. The well standardized gravimetric approach was adopted
to maintain the specific stress regime (100% and 60% FC)The expression
profile of few genes associated with wax biosynthesis was assessed in two
contrasting genotypes differing in EWC found to be higher in high wax
genotypes and stressed plants. Analysis of the composition of waxes
revealed important variations between high and low wax types.