Mutations at the LYS3 locus in barley have multiple effects on grain development, including an increase in embryo size and a decrease in endosperm starch content. The gene underlying LYS3 was identified by genetic mapping and mutations in this gene were identified in all four barley lys3 alleles. LYS3 encodes a transcription factor called Prolamin Binding Factor (PBF). Its role in controlling embryo size was confirmed using wheat TILLING mutants. To understand how PBF controls embryo development, we studied its spatial and temporal patterns of expression in developing grains. The PBF gene is expressed in both the endosperm and the embryos, but the timing of expression in these organs differs. PBF expression in wild-type embryos precedes the onset of embryo enlargement in lys3 mutants, suggesting that PBF suppresses embryo growth. We predicted the down-stream target genes of PBF in wheat and found them to be involved in a wide range of biological processes, including organ development and starch metabolism. Our work suggests that PBF may influence embryo size and endosperm starch synthesis via separate gene control networks.

中文翻译：

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LYS3 编码控制大麦和小麦胚胎生长的醇溶蛋白盒结合转录因子

大麦中 LYS3 基因座的突变对谷物发育有多种影响，包括胚胎大小的增加和胚乳淀粉含量的减少。通过遗传作图鉴定了 LYS3 的潜在基因，并且在所有四个大麦 lys3 等位基因中都鉴定了该基因的突变。LYS3 编码一种称为醇溶蛋白结合因子 (PBF) 的转录因子。使用小麦 TILLING 突变体证实了它在控制胚胎大小方面的作用。为了了解 PBF 如何控制胚胎发育，我们研究了其在发育中的谷物中表达的空间和时间模式。PBF 基因在胚乳和胚胎中均有表达，但在这些器官中的表达时间不同。野生型胚胎中的 PBF 表达先于 lys3 突变体中胚胎增大的开始，这表明 PBF 抑制胚胎生长。我们预测了小麦中 PBF 的下游靶基因，发现它们参与了广泛的生物过程，包括器官发育和淀粉代谢。我们的工作表明，PBF 可能通过单独的基因控制网络影响胚胎大小和胚乳淀粉合成。