The amino acid transporter OsAAP4 contributes to rice tillering and grain yield by regulating neutral amino acid allocation through two splicing variants

Abstract

Background: Amino acids, which are transported by amino acid transporters, are the major forms of organic nitrogen utilized by higher plants. Among the 19 Amino Acid Permease transporters (AAPs) in rice, only a small number of these genes have been reported to influence rice growth and development. However, whether other OsAAPs are responsible for rice growth and development is unclear.Results: In this study, we demonstrate that OsAAP4 promoter sequences are divergent between Indica and Japonica, with higher expression in the former, which produces more tillers and higher grain yield than does Japonica. Overexpression of two different splicing variants of OsAAP4 in Japonica ZH11 significantly increased rice tillering and grain yield as result of enhancing the neutral amino acid concentrations of Val, Pro, Thr and Leu. OsAAP4 RNA interference (RNAi) and mutant lines displayed opposite trends compared with overexpresing (OE) lines. In addition, exogenous Val or Pro at 0.5 mM significantly promoted the bud outgrowth of lines overexpressing an OsAAP4a splicing variant compared with ZH11, and exogenous Val or Pro at 2.0 mM significantly enhanced the bud outgrowth of lines overexpressing splicing variant OsAAP4b compared with ZH11. Of note, the results of a protoplast amino acid-uptake assay showed that Val or Pro at different concentrations was specifically transported and accumulated in these overexpressing lines. Transcriptome analysis further demonstrated that OsAAP4 may affect nitrogen transport and metabolism, and auxin, cytokinin signaling in regulating rice tillering.Conclusion: Our results suggested that OsAAP4 contributes to rice tiller and grain yield by regulating neutral amino acid allocation through two different splicing variants and that OsAAP4 might have potential applications in rice breeding.

An amino acid transporter‐like protein (OsATL15) facilitates the systematic distribution of thiamethoxam in rice for controlling the brown planthopper

“…Most of the AAPs mediated amino acid transport with different affinities, and some of them are responsible for rice growth and development (Taylor et al., 2015). Overexpression of OsAAP1 , OsAAP4 , OsAAP5 , and OsAAP6 could change amino acid homeostasis in rice and enhance bud outgrowth, grain yield, and also grain protein content (Fang et al., 2021; Ji et al., 2020; Peng et al., 2014; Wang et al., 2019). However, blocking OsAAP3 expression results in decreased Arg, Lys, Asp, and Thr levels, and unexpectedly, promotes rice tiller and grain yield (Lu et al., 2018).…”

Analysis of Potato Physiological and Biochemical Adaptable Mechanism in Response to Water and Nitrogen Interaction

“…Here, differential expression was detected in Here, 34 key candidate genes that responded to changes in water and nitrogen levels were identi ed via WGCNA. Several of the candidates, including MYB (Wang et al 2020), DOF(Kushwaha et al 2008), an amino acid transporter(Fang et al 2021), and aquaporin(Gao et al 2018), have been reported to play important roles in nitrogen uptake and utilization. In conclusion, the key genes identi ed in this study are promising candidate molecular targets for future improvement of water and fertilizer use e ciency in potato.…”