Center of Applied Biotechnology, Wuhan Institute of Bioengineering, Wuhan 430415, China.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China.
Plant Physiol. 2019 Jun;180(2):1031-1045. doi: 10.1104/pp.19.00034. Epub 2019 Mar 19.
As fundamental nutrients, amino acids are important for rice () growth and development. Here, we identified the amino acid permease 5 (OsAAP5), that regulates tiller number and grain yield in rice. The promoter sequence differed between and rice varieties. Lower expression of in the young leaf blade in varieties than in varieties was associated with more tillers in than in Down-regulation of expression in using RNA interference (RNAi) and clustered regularly interspaced short palindromic repeats led to increases in tiller number and grain yield, whereas overexpression (OE) had the opposite effect. Both a protoplast amino acid uptake assay and HPLC analysis indicated that more basic (Lys, Arg) and neutral (Val, Ala) amino acids were transported and accumulated in the OE lines than in the wild type, but the opposite was observed in the RNAi lines. Furthermore, exogenous application of Lys, Arg, Val, and Ala in the OE lines substantially inhibited tiller bud elongation, but the effect was lost in the RNAi lines. Notably, concentrations of the cytokinins cis-zeatin and dihydrozeatin were much lower in the OE lines than in the wild type, whereas concentrations in the RNAi lines were higher. Thus, could regulate tiller bud outgrowth by affecting cytokinin levels, and knockout of could be valuable for breeding programs seeking high yield and grain quality.
作为基本营养素，氨基酸对水稻的生长和发育很重要。在这里，我们鉴定了氨基酸通透酶 5（OsAAP5），它调节水稻分蘖数和产量。和 水稻品种的 启动子序列不同。在 品种的幼叶中表达量低于 品种，与 品种的分蘖数多于 品种有关。使用 RNA 干扰（RNAi）下调 的表达导致分蘖数和产量增加，而 过表达（OE）则产生相反的效果。原生质体氨基酸摄取测定和 HPLC 分析均表明，OE 系中更多的碱性（Lys、Arg）和中性（Val、Ala）氨基酸被转运和积累，但在 RNAi 系中则相反。此外，在 OE 系中添加外源性 Lys、Arg、Val 和 Ala 可显著抑制分蘖芽伸长，但在 RNAi 系中则没有这种效果。值得注意的是，OE 系中的细胞分裂素顺式玉米素和二氢玉米素的浓度明显低于野生型，而 RNAi 系中的浓度较高。因此，可能通过影响细胞分裂素水平来调节分蘖芽的生长，而敲除可能对寻求高产和优质的育种计划很有价值。
