Many shrunken endosperm mutants of barley (Hordeum vulgare L.) have been described and several of these are known to have lesions in starch biosynthesis genes. Here we confirm that one type of shrunken endosperm mutant, lys3 (so called because it was first identified as a high-lysine mutant) has an additional phenotype: as well as shrunken endosperm it also has enlarged embryos. The lys3 embryos have a dry weight that is 50–150% larger than normal. Observations of developing lys3 embryos suggest that they undergo a form of premature germination and the mature lys3 grains show reduced dormancy. In many respects, the phenotype of barley lys3 is similar to that of rice GIANT EMBRYO mutants (affected in the OsGE gene). However, the barley orthologue of OsGE is located on a different chromosome from Lys3. Together these results suggest that the gene underlying Lys3 is unlikely to encode a starch biosynthesis protein but rather a protein influencing grain development.

中文翻译：

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大麦 lys3 突变体在胚乳萎缩突变体中是独一无二的，具有异常大的胚胎

已经描述了许多大麦 (Hordeum vulgare L.) 的萎缩胚乳突变体，其中一些已知在淀粉生物合成基因中具有损伤。在这里，我们确认一种类型的萎缩胚乳突变体 lys3（之所以这么称呼，是因为它首先被鉴定为高赖氨酸突变体）具有额外的表型：除了萎缩的胚乳外，它还具有增大的胚胎。lys3 胚胎的干重比正常值大 50-150%。对发育中的 lys3 胚胎的观察表明，它们经历了某种形式的过早发芽，成熟的 lys3 颗粒显示出休眠减少。在许多方面，大麦 lys3 的表型与水稻 GIANT EMBRYO 突变体（受 OsGE 基因影响）相似。然而，OsGE 的大麦直系同源物位于与 Lys3 不同的染色体上。