The auxin-responsive GH3 gene family in rice (Oryza sativa)

Abstract

Auxin regulates plant growth and development by altering the expression of diverse genes. Among these, the genes of Aux/IAA, SAUR, and GH3 classes have been extensively studied in dicots, but little information is available on monocots. We have identified 12 members of GH3 gene family in rice using sequences of full-length cDNA clones available from KOME and analysis of the whole genome sequence of rice. The genomic organization as well as chromosomal location of all the OsGH3 genes is reported. The rice GH3 proteins can be classified in two groups (groups I and II) on the basis of their phylogenetic relationship with Arabidopsis GH3 proteins. Based upon the sequences available in the database, not a single group III GH3 protein could be identified in rice. An extensive survey of EST sequences of other monocots led to the conclusion that although GH3 gene family is highly conserved in both dicots and monocots but the group III is conspicuous by its absence in monocots. The in silico analysis has been complemented with experimental data to quantify transcript levels of all GH3 gene family members. Using real-time polymerase chain reaction, the organ-specific expression of individual OsGH3 genes in light- and dark-grown seedlings/plants has been examined. The transcript abundance of nearly all OsGH3 genes is enhanced on auxin treatment, with the effect more pronounced on OsGH3-1, -2, and -4. The functional validation of these genes in transgenics or analysis of gene-specific insertional mutants will help in elucidating their precise role in auxin signal transduction.

Arabidopsis thaliana GH3.9 influences primary root growth

“…Our results are consistent with publicly available microarray gene expression data indicating that GH3.9 is repressed by exogenous IAA (Genevestigator; http://www.genevestigator.ethz.ch/ ). Moreover, phylogenetic analyses indicate that AtGH3.9 and rice OsGH3.11 are orthologues, and OsGH3.11 expression was also unaffected or repressed by exogenous auxin (Jain et al 2006;Terol et al 2006).…”

“…GH3 homologues are found in other plant species. The recently classified rice GH3 gene family has members corresponding to Groups I and II, but Group III members were not reported (Jain et al 2006;Terol et al 2006). The GH3 families have not been extensively studied in species other than rice and Arabidopsis.…”

Activation of the Indole-3-Acetic Acid–Amido Synthetase GH3-8 Suppresses Expansin Expression and Promotes Salicylate- and Jasmonate-Independent Basal Immunity in Rice

“…In Arabidopsis, some GH3 proteins are adenylate-forming enzymes that conjugate amino acids to the auxin indole-3-acetic acid (IAA) or to JA or SA (Staswick et al, 2002(Staswick et al, , 2005. The rice GH3 gene family consists of at least 12 members (Jain et al, 2006b). Aux/IAA proteins are transcription factors acting as repressors in auxinregulated gene expression.…”

“…Our previous study showed that cDNA clone EI5P11, corresponding to GH3-8, a member of the rice GH3 gene family (Jain et al, 2006b), was pathogen-responsive (Wen et al, 2003). EI5P11 expression increased after inoculation with either incompatible pathogens in rice lines that carried different R genes conferring resistance to Xanthomonas oryzae pv oryzae (Xoo), the cause of bacterial blight disease, or to Magnaporthe grisea, the cause of fungal blast disease, or a compatible pathogen in a susceptible rice line.…”

Structural basis of jasmonate-amido synthetase FIN219 in complex with glutathione S-transferase FIP1 during the JA signal regulation

“…jasmonate response | far-red light | signaling cross-talk | adenylation enzyme | phytohormone F ar-red (FR) insensitive 219 (FIN219) (1), also known as jasmonate (JA) resistant 1 (JAR1; AtGH3.11) (2), is a member of the auxin-regulated Gretchen Hagen 3 (GH3) family of proteins (3). The GH3 family in Arabidopsis is composed of 19 distinct proteins and is also conserved in plants such as rice (4)(5)(6), tomato (7,8), and maize (9), with 13, 15, and 13 members, respectively. Phylogenetically, the GH3 family is classified as part of the adenylate-forming enzyme superfamily, which contains proteins such as firefly luciferase-like enzymes (10).…”