Crop Genetics Department, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
Plant J. 2011 Jun;66(6):929-40. doi: 10.1111/j.1365-313X.2011.04555.x. Epub 2011 Apr 4.
In a survey of the BrachyTAG mutant population of Brachypodium distachyon, we identified a line carrying a T-DNA insertion in one of the two eukaryotic initiation factor 4A (eIF4A) genes present in the nuclear genome. The eif4a homozygous mutant plants were slow-growing, and exhibited reduced final plant stature due to a decrease in both cell number and cell size, consistent with roles for eIF4A in both cell division and cell growth. Hemizygous plants displayed a semi-dwarfing phenotype, in which stem length was reduced but leaf length was normal. Linkage between the insertion site and phenotype was confirmed, and we show that the level of eIF4A protein is strongly reduced in the mutant. Transformation of the Brachypodium homozygous mutant with a genomic copy of the Arabidopsis eIF4A-1 gene partially complemented the growth phenotype, indicating that gene function is conserved between mono- and dicotyledonous species. This study identifies eIF4A as a novel dose-dependent regulator of stem elongation, and demonstrates the utility of Brachypodium as a model for grass and cereals research.
在对拟南芥 Brachypodium distachyon 的 BrachyTAG 突变体群体进行调查时，我们在核基因组中存在的两个真核起始因子 4A (eIF4A) 基因之一中鉴定出一个携带 T-DNA 插入的品系。eif4a 纯合突变体植物生长缓慢，由于细胞数量和细胞大小减少，最终植物株高降低，这与 eIF4A 在细胞分裂和细胞生长中的作用一致。半合子植物表现出半矮化表型，其中茎长缩短，但叶片长度正常。插入位点与表型之间的连锁关系得到了证实，我们表明突变体中 eIF4A 蛋白的水平显著降低。用拟南芥 eIF4A-1 基因的基因组拷贝转化拟南芥纯合突变体部分弥补了生长表型，表明基因功能在单子叶和双子叶物种之间是保守的。本研究将 eIF4A 鉴定为茎伸长的新型剂量依赖性调节因子，并证明了拟南芥作为禾本科和谷类研究模型的实用性。
