Abstract: Wheat is the first and the most important grain of the
world and its bakery property is due to glutenin and gliadin qualities.
Wheat seed proteins were divided into four groups according to
solubility including albumin, globulin, glutenin and prolamin or
gliadin. Gliadins are major components of the storage proteins in
wheat endosperm. It seems that little information is available about
gliadin genes in Iranian wild relatives of wheat. Thus, the aim of this
study was the evaluation of the wheat wild relatives collected from
different origins of Zagros Mountains in Iran, in terms of coding
gliadin genes using specific primers. For this, forty accessions of
Triticum boeoticum and Triticum urartu were selected for this study.
For each accession, genomic DNA was extracted and PCRs were
performed in total volumes of 15 μl. The amplification products were
separated on 1.5% agarose gels. In results, for Gli-2A locus three
allelic variants were detected by Gli-2As primer pairs. The sizes of
PCR products for these alleles were 210, 490 and 700 bp. Only five
(13%) and two accessions (5%) produced 700 and 490 bp fragments
when their DNA was amplified with the Gli.As.2 primer pairs.
However, 93% of the accessions carried allele 210 bp, and only 8%
did not any product for this marker. Therefore, these germplasm
could be used as rich gene pool to broaden the genetic base of bread
wheat.
Abstract: Rice seed expression (cDNA) library in the Lambda
Zap 11® phage constructed from the developing grain 10-20 days
after flowering was transformed into yeast for functional
complementation assays in three salt sensitive yeast mutants S.
cerevisiae strain CY162, G19 and Axt3K. Transformed cells of G19
and Axt3K with pYES vector with cDNA inserts showed enhance
tolerance than those with empty pYes vector. Sequencing of the
cDNA inserts revealed that they encode for the putative proteins with
the sequence homologous to rice putative protein PROLM24
(Os06g31070), a prolamin precursor. Expression of this cDNA did
not affect yeast growth in absence of salt. Axt3k and G19 strains
expressing the PROLM24 were able to grow upto 400 mM and 600
mM of NaCl respectively. Similarly, Axt3k mutant with PROLM24
expression showed comparatively higher growth rate in the medium
with excess LiCl (50 mM). The observation that expression of
PROLM24 rescued the salt sensitive phenotypes of G19 and Axt3k
indicates the existence of a regulatory system that ameliorates the
effect of salt stress in the transformed yeast mutants. However, the
exact function of the cDNA sequence, which shows partial sequence
homology to yeast UTR1 is not clear. Although UTR1 involved in
ferrous uptake and iron homeostasis in yeast cells, there is no
evidence to prove its role in Na+ homeostasis in yeast cells. Absence
of transmembrane regions in Os06g31070 protein indicates that salt
tolerance is achieved not through the direct functional
complementation of the mutant genes but through an alternative
mechanism.