Indeterminate domain 10regulates ammonium‐mediated gene expression in rice roots

Abstract

SummaryIndeterminate domain (IDD) genes are a family of plant transcriptional regulators that function in the control of development and metabolism during growth. Here, the function of Oryza sativa indeterminate domain 10 (OsIDD10) has been explored in rice plants. Compared with wild-type roots, idd10 mutant roots are hypersensitive to exogenous ammonium. This work aims to define the action of IDD10 on gene expression involved in ammonium uptake and nitrogen (N) metabolism.The ammonium induction of key ammonium uptake and assimilation genes was examined in the roots of idd10 mutants and IDD10 overexpressors. Molecular studies and transcriptome analysis were performed to identify target genes and IDD10 binding cis-elements.IDD10 activates the transcription of AMT1;2 and GDH2 by binding to a cis-element motif present in the promoter region of AMT1;2 and in the fifth intron of GDH2. IDD10 contributes significantly to the induction of several genes involved in N-linked metabolic and cellular responses, including genes encoding glutamine synthetase 2, nitrite reductases and trehalose-6-phosphate synthase. Furthermore, the possibility that IDD10 might influence the Nmediated feedback regulation of target genes was examined.This study demonstrates that IDD10 is involved in regulatory circuits that determine N-mediated gene expression in plant roots.

Transcription Factor OsDOF18 Controls Ammonium Uptake by Inducing Ammonium Transporters in Rice Roots

“…The level of ammonium uptake was significantly lower in osdof18 mutants than in the WT. This ammonium-dependent phenotype was similar to that described for osidd10 , which displays delayed germination and slower primary root growth when the medium is supplemented only with ammonium (Xuan et al, 2013). However, the molecular mechanisms involved in ammonium uptake are apparently different between OsIDD10 and OsDOF18.…”

“…Three OsAMT1 genes show distinct expression patterns: OsAMT1;1 is constitutively expressed in shoots while OsAMT1;2 and OsAMT1;3 are expressed specifically in roots (Sonoda et al, 2003). OsAMT1;1 and OsAMT1;2 are up-regulated in plants following exposure to ammonium, whereas OsAMT1;3 is up-regulated by N-deprivation (Kumar et al, 2003; Sonoda et al, 2003; Suenaga et al, 2003; Xuan et al, 2013). Overexpression of OsAMT1;1 results in higher production of biomass with increased amounts of ammonium and glutamine (Ranathunge et al, 2014).…”

A major QTL controlling deep rooting on rice chromosome 4

“…We also compared the positions of DRO2 and known root genes characterized in mutants by using the Overview of functionally characterized Genes in Rice Online database (OGRO, http://qtaro.abr.affrc.go.jp/ogro)25. We found three root-related genes, DWARF176 26, Oryza sativa indeterminate domain 10 27, and GLR3.1 28, in the DRO2 LOD support interval, but none of them has been reported to affect the root growth angle. Therefore, DRO2 might be distinct from these known genes.…”

Regulatory role of indeterminate domain 10 (IDD10) in ammonium-dependent gene expression in rice roots

“…The ammonium-dependent root phenotypes of idd10 mutants also can be rescued in MS media containing methionine-S-sulfoximine (MSO), which prevents ammonium assimilation by glutamine synthetase. 3 The expression of ammonium transporters (AMTs) and assimilation genes (GS, NADH-GOGAT, GDH) is highly sensitive to exogenous ammonium. [4][5][6] The expression levels of AMT1;2 (ammonium transporter 1;2) and GDH2 (glutamate dehydrogenase 2) in the roots of idd10 mutants and IDD10 overexpressors were suppressed and enhanced, respectively.…”