Two splicing variants of amino acid transporter-like 4 (OsATL4) negatively regulate rice tillering and yield by mediating the transport of amino acids
Chuanbo Wang,
Weiting Huang,
Rui Miao,
Bowen Wu,
Wenhao Wu,
Chongchong He,
Chang Zheng,
Quanzhi Zhao,
Zhongming Fang
Affiliations
Chuanbo Wang
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, Guizhou, China
Weiting Huang
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, Guizhou, China
Rui Miao
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, Guizhou, China
Bowen Wu
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, Guizhou, China
Wenhao Wu
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, Guizhou, China
Chongchong He
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, Guizhou, China
Chang Zheng
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, Guizhou, China
Quanzhi Zhao
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, Guizhou, China
Zhongming Fang
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, Guizhou, China; Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Guizhou University, Guiyang 550025, Guizhou, China; Corresponding author.
Amino acids are the primary form of nitrogen utilization in higher plants, mainly transported by amino acid transporters. In this study, we analyzed the natural variation of amino acid transporter-like 4 (OsATL4) in rice germplasm resources, identified its spatiotemporal expression characteristics, determined its substrate transport, and validated its function using transgenic plants. We found that the promoter sequence of OsATL4 varied across 498 rice varieties. The expression level of OsATL4 was higher in japonica rice, which was negatively correlated with tiller number and grain yield. OsATL4 was highly expressed in the basal part, leaf sheath, stem, and young panicle, with its two splicing variants localized to the cell membrane. OsATL4a (the long splicing variant) had a high affinity for transporting Ser, Leu, Phe, and Thr, while OsATL4b (the short splicing variant) had a high affinity for transporting Ser, Leu, and Phe. Blocking OsATL4 promoted axillary bud outgrowth, rice tillering, and grain yield, whereas overexpression lines exhibited the opposite phenotype. Exogenous application of low concentrations of Ser promoted axillary bud outgrowth in overexpression lines, while high concentrations of Ser inhibited it. Conversely, the mutant lines showed the opposite response. Altered expression of OsATL4 might affect the expression of genes in nitrogen, auxin, and cytokinin pathways. We propose that two splicing variants of OsATL4 negatively regulate rice tillering and yield by mediating the transport of amino acids, making it a significant target for high-yield rice breeding.
