Characterization of gibberellin receptor mutants of barley (Hordeum vulgare L.)
Characterization of gibberellin receptor mutants of barley (Hordeum vulgare L.)
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DOI：
10.1093/mp/ssn002
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发表时间：
2008-03-01
期刊：
影响因子：
27.5
通讯作者：
Mander, Lewis N.
中科院分区：
文献类型：
--
作者：
Chandler, Peter M.;Harding, Carol A.;Mander, Lewis N.
利用水稻赤霉素（GA）受体基因Gid 1的序列鉴定了一个大麦直向同源基因。这在E.大肠杆菌，并产生一种蛋白，能够结合GA在体外与结构特异性和饱和性。它在GA反应的潜在作用进行了研究，使用大麦突变体减少GA敏感性（gse 1突变体）。16个不同的gse 1突变体在这个序列中每个都携带一个独特的核苷酸替换。在所有情况下，除了一种情况外，这些变化导致单个氨基酸取代，并且对于剩余的突变体，提出mRNA的5'非翻译区中的取代干扰翻译起始。新的突变等位基因和gse 1表型之间的分离群体中有完美的连锁，导致的结论是，在大麦中的假定的GID 1 GA受体序列对应于Gse 1基因座。测定其中一个突变体的内源GA含量，发现生物活性GA（1）的积累增加，C-20 GA前体的不足。所有gse 1突变体对外源GA（3）和AC 94377（GA类似物）在正常“饱和”浓度下的敏感性降低，但在高得多的浓度下，通常有相当大的反应。大麦和水稻突变体之间的比较揭示了这两个谷类物种在GA激素生理学上的有趣差异。
The sequence of Gid1 (a gene for a gibberellin (GA) receptor from rice) was used to identify a putative orthologue from barley. This was expressed in E. coli, and produced a protein that was able to bind GA in vitro with both structural specificity and saturability. Its potential role in GA responses was investigated using barley mutants with reduced GA sensitivity (gse1 mutants). Sixteen different gse1 mutants each carried a unique nucleotide substitution in this sequence. In all but one case, these changes resulted in single amino acid substitutions, and, for the remaining mutant, a substitution in the 5' untranslated region of the mRNA is proposed to interfere with translation initiation. There was perfect linkage in segregating populations between new mutant alleles and the gse1 phenotype, leading to the conclusion that the putative GID1 GA receptor sequence in barley corresponds to the Gse1 locus. Determination of endogenous GA contents in one of the mutants revealed enhanced accumulation of bioactive GA(1), and a deficit of C-20 GA precursors. All of the gse1 mutants had reduced sensitivity to exogenous GA(3), and to AC94377 (a GA analogue) at concentrations that are normally 'saturating`, but, at much higher concentrations, there was often a considerable response. The comparison between barley and rice mutants reveals interesting differences between these two cereal species in GA hormonal physiology.