Molecular analysis of genes involving in the agronomic characteristics of 'uzu' and 'preharvest sprouting' in barley [Hordeum vulgare] and wheat [Triticum aestivum]
2007
Chono, M.(National Inst. of Crop Science, Tsukuba, Ibaraki (Japan))
To investigate the important agricultural characters of barley 'uzu' and 'sprouting', the molecular analysis was performed. The semi-dwarf characteristic leading to lodging resistance is very important for high yields. Semi-dwarf barley accessions carrying the 'uzu' gene, called 'uzu' barley in Japan, are non-responding to brassinolide and accumulate brassinosteroids (BRs). We cloned the barley homolog of the BR-receptor gene, HvBRI1, a candidate for the uzu gene suggested by the marker synteny of rice and barley chromosomes. The comparison of HvBRI11 sequences in uzu and normal lines demonstrated that the uzu phenotype is correlated with a missense mutation in the HvBRI1 gene. Pre-harvest sprouting of cereal grain damages the quality of the end product. To investigate whether the regulation of abscisic acid (ABA) content is related to germinability during grain development under field conditions. cDNAs for key ABA biosynthetic and catabolic enzymes (9-cis-epoxycarotenoid dioxygenase and ABA 8'-hydroxylase) were cloned from barley. Expression and ABA-quantification analysis demonstrated that the change in the ABA content of imbibing grains following dormancy release is likely to reflect changes in the expression patterns of these genes. The varied expression levels of these genes, which would have effects on the activity of ABA biosynthesis and catabolism, might be reflected in the germinability of field-grown barley.
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