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Systems approach identifies TGA 1 and TGA 4 transcription factors as important regulatory components of the nitrate response of A rabidopsis thaliana roots
Author(s) -
Alvarez José M.,
Riveras Eleodoro,
Vidal Elena A.,
Gras Diana E.,
ContrerasLópez Orlando,
Tamayo Karem P.,
Aceituno Felipe,
Gómez Isabel,
Ruffel Sandrine,
Lejay Laurence,
Jordana Xavier,
Gutiérrez Rodrigo A.
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12618
Subject(s) - arabidopsis , mutant , chromatin immunoprecipitation , arabidopsis thaliana , transcription factor , lateral root , transcription (linguistics) , biology , gene , microbiology and biotechnology , gene expression , promoter , nitrate , genetics , ecology , linguistics , philosophy
Summary Nitrate acts as a potent signal to control global gene expression in A rabidopsis. Using an integrative bioinformatics approach we identified TGA 1 and TGA 4 as putative regulatory factors that mediate nitrate responses in A rabidopsis roots. We showed that both TGA 1 and TGA 4 m RNA s accumulate strongly after nitrate treatments in roots. Global gene expression analysis revealed 97% of the genes with altered expression in tga1 tga4 double mutant plants respond to nitrate treatments, indicating that these transcription factors have a specific role in nitrate responses in Arabidopsis root organs. We found TGA 1 and TGA 4 regulate the expression of nitrate transporter genes NRT 2.1 and NRT 2.2 . Specific binding of TGA 1 to its cognate DNA sequence on NRT 2.1 and NRT 2.2 promoters was confirmed by chromatin immunoprecipitation assays. The tga1 tga4 double mutant plants exhibit nitrate‐dependent lateral and primary root phenotypes. Lateral root initiation is affected in both tga1 tga4 and nrt1.2 nrt2.2 double mutants, suggesting TGA 1 and TGA 4 regulate lateral root development at least partly via NRT 2.1 and NRT 2.2. Additional root phenotypes of tga1 tga4 double mutants indicate that these transcription factors play an important role in root developmental responses to nitrate. These results identify TGA 1 and TGA 4 as important regulatory factors of the nitrate response in A rabidopsis roots.