Institute of Rice Industry Technology Research, Key Laboratory of Functional Agriculture of Guizhou Provincial, Department of Education, Key Laboratory of Molecular Breeding for Grain and oil Crops in Guizhou Province, College of Agricultural Sciences, Guizhou University, Guiyang, 550025, China.
Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Guizhou University, Guiyang, 550025, China.
BMC Plant Biol. 2024 May 23;24(1):447. doi: 10.1186/s12870-024-05159-5.
Amino acids are not only the main form of N in rice, but also are vital for its growth and development. These processes are facilitated by amino acid transporters within the plant. Despite their significance, only a few AAP amino acid transporters have been reported.
In this study, we observed that there were differences in the expression of amino acid transporter OsAAP7 among 521 wild cultivated rice varieties, and it directly negatively correlated with tillering and grain yield per plant. We revealed that OsAAP7 protein was localized to the endoplasmic reticulum and had absorption and transport affinity for amino acids such as phenylalanine (Phe), lysine (Lys), leucine (Leu), and arginine (Arg) using subcellular localization, yeast substrate testing, fluorescent amino acid uptake, and amino acid content determination. Further hydroponic studies showed that exogenous application of amino acids Phe, Lys and Arg inhibited the growth of axillary buds in the overexpression lines, and promoted the elongation of axillary buds in the mutant lines. Finally, RNA-seq analysis showed that the expression patterns of genes related to nitrogen, auxin and cytokinin pathways were changed in axillary buds of OsAAP7 transgenic plants.
This study revealed the gene function of OsAAP7, and found that blocking of amino acid transporter OsAAP7 with CRISPR/Cas9 technology promoted tillering and yield by determining basic and neutral amino acids accumulation in rice.
氨基酸不仅是水稻中氮的主要存在形式，而且对其生长和发育也至关重要。这些过程是由植物内的氨基酸转运蛋白来完成的。尽管它们很重要，但目前只报道了少数几种 AAP 氨基酸转运蛋白。
本研究观察到，在 521 个野生栽培稻品种中，氨基酸转运蛋白 OsAAP7 的表达存在差异，它与分蘖和每株产量直接呈负相关。我们揭示了 OsAAP7 蛋白定位于内质网，并且对苯丙氨酸（Phe）、赖氨酸（Lys）、亮氨酸（Leu）和精氨酸（Arg）等氨基酸具有吸收和转运亲和力，这是通过亚细胞定位、酵母底物测试、荧光氨基酸摄取和氨基酸含量测定得出的。进一步的水培研究表明，外源添加氨基酸 Phe、Lys 和 Arg 抑制了过表达系中腋芽的生长，而促进了突变系中腋芽的伸长。最后，RNA-seq 分析表明，OsAAP7 转基因植物腋芽中与氮、生长素和细胞分裂素途径相关的基因表达模式发生了变化。
本研究揭示了 OsAAP7 的基因功能，并发现通过 CRISPR/Cas9 技术阻断氨基酸转运蛋白 OsAAP7 可以促进分蘖和产量，这是通过确定水稻中基本和中性氨基酸的积累来实现的。
