Center of Applied Biotechnology, Wuhan Institute of Bioengineering, Wuhan, China.
National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.
Plant Biotechnol J. 2018 Oct;16(10):1710-1722. doi: 10.1111/pbi.12907. Epub 2018 Mar 25.
Amino acid transporters (AATs) play indispensable roles in nutrient allocation during plant development. In this study, we demonstrated that inhibiting expression of the rice amino acid transporter OsAAP3 increased grain yield due to a formation of larger numbers of tillers as a result of increased bud outgrowth. Elevated expression of OsAAP3 in transgenic plants resulted in significantly higher amino acid concentrations of Lys, Arg, His, Asp, Ala, Gln, Gly, Thr and Tyr, and inhibited bud outgrowth and rice tillering. However, RNAi of OsAAP3 decreased significantly Arg, Lys, Asp and Thr concentrations to a small extent, and thus promoted bud outgrowth, increased significantly tiller numbers and effective panicle numbers per plant, and further enhanced significantly grain yield and nitrogen use efficiency (NUE). The promoter sequences of OsAAP3 showed some divergence between Japonica and Indica rice, and expression of the gene was higher in Japonica, which produced fewer tillers than Indica. We generated knockout lines of OsAAP3 on Japonica ZH11 and KY131 using CRISPR technology and found that grain yield could be increased significantly. These results suggest that manipulation of OsAAP3 expression could be used to increase grain yield in rice.
氨基酸转运蛋白（AATs）在植物发育过程中的养分分配中发挥着不可或缺的作用。在本研究中，我们证明了抑制水稻氨基酸转运蛋白 OsAAP3 的表达会由于芽生长增加而形成更多的分蘖，从而增加粒重。转基因植物中 OsAAP3 的过表达导致赖氨酸、精氨酸、组氨酸、天冬氨酸、丙氨酸、谷氨酰胺、甘氨酸、苏氨酸和酪氨酸的氨基酸浓度显著升高，并抑制芽生长和水稻分蘖。然而，OsAAP3 的 RNAi 显著降低了精氨酸、赖氨酸、天冬氨酸和苏氨酸的浓度，但程度较小，从而促进了芽生长，显著增加了每个植物的分蘖数和有效穗数，并进一步显著提高了粒重和氮利用效率（NUE）。OsAAP3 的启动子序列在粳稻和籼稻之间存在一定的差异，基因的表达在粳稻中更高，而粳稻比籼稻产生的分蘖更少。我们使用 CRISPR 技术在粳稻 ZH11 和 KY131 上生成了 OsAAP3 的敲除系，发现粒重可以显著增加。这些结果表明，操纵 OsAAP3 的表达可以用于增加水稻的粒重。
