PMC

Phylogenetic relationship among type-A response regulator proteins from rice (OsRR), maize (ZmRR), and Arabidopsis (ARR). The unrooted tree was generated using ClustalX program by neighbor-joining method and visualized by Treeview. Scale bar represents 0.1 amino acid substitution per site.

Changes in transcript levels of the OsRR6 gene in response to different stress treatments. The transcript levels of OsRR6 gene in 6-day-old light-grown seedlings treated with ABA, NaCl, mannitol and cold for 6 h, were plotted as the relative expression (fold) of the seedlings mock-treated for the same duration.

Real-time PCR analysis showing the organ-specific expression profiles of individual OsRR genes. The relative mRNA levels of individual OsRR genes normalized with respect to housekeeping gene, UBQ5, in different tissues (GS, green seedlings; ES, etiolated seedlings; S, green shoots; R, roots; ML, mature leaves; F, flowers) are presented.

Expression profiles of the OsRR genes in response to different hormones and cycloheximide. The transcript levels of each OsRR gene in 6-day-old light-grown seedlings treated with IAA, Ebr, GA3, ACC, BAP, CHX and CHX+BAP for 3 h, were plotted as the relative expression (fold) of the seedlings mock-treated for the same duration.

Kinetics of induction of OsRR genes in response to cytokinin. The transcript levels of each OsRR gene in 6-day-old light-grown seedlings treated with BAP for 15 min, 30 min, 1 h, 3 h and 6 h, were plotted as the relative expression (fold) of the seedlings mock-treated for the same duration.

Type-A response regulators in rice. (A) Exon-intron organization of OsRR genes. Exons and introns are represented by black boxes and lines, respectively. (B) Schematic representation of OsRR proteins (aligned with respect to the second conserved Asp (D) residue). The conserved receiver domain is represented as gray box with D-D-K residues. The black vertical bars represent intron position. The numbers 0, 1 and 2 above the vertical bars represent the phase 0, 1 and 2 introns, respectively. (C) Multiple alignments of the OsRR proteins obtained with ClustalX. Fully and partially conserved (present in more than 50% of aligned sequences) residues are highlighted in black and gray boxes, respectively. Gaps (marked with dashes) have been introduced to maximize the alignments. The conserved receiver domain has been underlined. Conserved Asp and Lys residues are marked with asterisks.