- The TIFY family is a novel plant-specific gene family involved in the regulation of diverse plant-specific biologic processes, such as development and responses to phytohormones, in Arabidopsis. However, there is limited information about this family in monocot species. This report identifies 20 TIFY genes in rice, the model monocot species. Sequence analysis indicated that rice TIFY proteins have conserved motifs beyond the TIFY domain as was previously shown in Arabidopsis. On the basis of their protein structures, members of the TIFY family can be divided into two groups. Transcript level analysis of OsTIFY genes in tissues and organs revealed different tempo- spatial expression patterns, suggesting that expression and function vary by stage of plant growth and development. Most of the OsTIFY genes were predominantly expressed in leaf. Nine OsTIFY genes were responsive to jasmonic acid and wounding treatments.
- The TIFY family is a novel plant-specific gene family recently identified in Arabidopsis. This family owes its name to a conserved TIFY domain with a highly conserved amino acid pattern of TIF [F/Y] XG in the protein sequences. The first gene identified from the TIFY family was originally reported as ZIM (Zinc-finger protein expressed in Inflorescence Meristem; At4g24470), which contains a C2C2-GATA zinc-finger. The nomenclature for TIFY, ZIM, and C2C2-GATA gene families had long been confusing, until Vanholme et al. (2007) conducted systematic sequence analysis to increase clarity. They identified all putative TIFY domain-containing members in Arabidopsis and introduced the name TIFY for the family.
- Recently, a subfamily of TIFY named JAZ (JASMO-NATE ZIM-DOMAIN) has been intensively investigated for its proteins’ roles as key regulators of jasmonate hormonal response in Arabidopsis. The 12 members of this subfamily contain the TIFY domain and a C-terminal conserved domain designated as Jas which has a characteristic motif of SLX 2 FX 2 KRX 2 RX 5 PY. Thines et al. (2007) and Chini et al. (2007) firstly reported the function of JAZs in Arabidopsis. Over-expression of a truncated JAZ1 gene lacking the Jas domain and the mutant of JAI3/JAZ3 gene (At3g17860), which encodes an aberrant protein also lacking the Jas domain but including 14 extra amino acids, showed a dominant jasm-onate-insensitive phenotype. The degradation of these JAZs was induced by JA in vivo, and JA-IIe was shown to promote CORONATINE-INSENSITIVE1 (COI1)-JAZ1 interaction in vitro. These pivotal findings established that JAZ proteins are targets for jasmonate-dependent degradation via the SCF COI1 26S proteasome pathway. The JAI3 was also found to interact with AtMYC2, which can regulate JAI3 gene expression via feedback.
- For OsTIFY11a, the PCR products were cloned into p1301H (modified based on pCAMBIA1301) which has the stress-inducible promoter of OsLEA3-I.
- JA signaling gene Os03g0180800 was up-regulated by FA exposure. Overexpression of ZIM-3 (Os03g0180800), a stress-inducible gene, was found to significantly increase tolerance to salt and dehydration stresses.
(non) over-expressed lines:
- four OsTIFY11a over-expressed lines:
- four non over-expressed lines:
- the over-expression of transgenic lines showed significantly increased tolerance to the stress treatments in terms of the shoot growth.
- OsTIFY11a-overexpressed lines accumulated significantly higher content of proline than the nonover-expressed lines under the salt stress conditions.
- When the seeds of OsTIFY11a transgenic plants were germinated on MS medium containing 75 mM NaCl, the over-expressed transgenic seeds had a significantly higher germination rate than the non-overexpressed transgenic seeds, but they showed no difference in germination rate on the normal MS medium.
- The full length cDNA of OsTIFY11a for overexpression was isolated from indica rice Minghui 63 and encodes a protein with the sequence as from japonica rice. OsTIFY11a and OsTIFY11e had similar induction dynamics: the induced expression peaked at 0.5 h after JA treatment.
- Over-expression of OsTIFY11a, one of the stress-inducible genes, resulted in significantly increased tolerance to salt and dehydration stresses. The OsTIFY11a gene was expressed in the 3–5 cm young panicles at a relatively high level. Interestingly, almost all of the OsTIFY genes with a high expression level in leaves had a very low expression level in the stamen.
- The transient gene expression assay using Arabidopsis mesophyll protoplasts showed that the OsTIFY11a-GFP fusion protein was colocalized with the reported rice transcription factor Ghd7 in the nucleus, suggesting that OsTIFY11a is a nuclear protein.
- A few OsTIFY gene clusters, including two OsTIFY gene clusters (OsTIFY11a, OsTIFY11b, and OsTIFY11c; OsTIFY11g and OsTIFY10a), on chromosome 3 and one gene cluster (OsTIFY11e, OsTIFY11f, and OsTIFY11d) on chromosome 10.
- OsTIFY11a contains a TIFY domain and a Jas motif, but two amino acids (Pro and Tyr) that were identified in the Jas motif are absent in OsTIFY11a.
- The 38 TIFY proteins were also classified into two major groups (I and II) according to the unrooted phylogenetic tree (Fig. 1). Four proteins with the GATA zincfinger and CCT domains (OsTIFY1a, 1b, 2a, and 2b) were clustered together in group I. The proteins without the GATA zinc-finger and CCT domains consist of the second major group (group II), and this group contains all the JAZ proteins of Arabidopsis and putative JAZ homologs in rice (OsTIFY3, 5, 6a, 6b, 9, 10a, 10b, 10c, 11a, 11b, 11c, 11d, 11e, 11f, and 11g).
The TIFY family is a novel plant-specific gene family involved in the regulation of diverse plant-specific biologic processes, such as development and responses to phytohormones, in Arabidopsis. However, there is limited information about this family in monocot species.
Labs working on this gene
- National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, 430070 Wuhan, China
- Ye H, Du H, Tang N, et al. Identification and expression profiling analysis of TIFY family genes involved in stress and phytohormone responses in rice[J]. Plant molecular biology, 2009, 71(3): 291-305.
- Chi W C, Chen Y A, Hsiung Y C, et al. Autotoxicity mechanism of Oryza sativa: transcriptome response in rice roots exposed to ferulic acid[J]. BMC genomics, 2013, 14(1): 351.
- Lee H Y, Seo J S, Cho J H, et al. Oryza sativa COI homologues restore jasmonate signal transduction in Arabidopsis coi1-1 mutants[J]. PloS one, 2013, 8(1): e52802.
- Shimizu T, Miyamoto K, Miyamoto K, et al. OsJAR1 contributes mainly to biosynthesis of the stress-induced jasmonoyl-isoleucine involved in defense responses in rice[J]. Bioscience, biotechnology, and biochemistry, 2013, 77(7): 1556-1564.
- Xiao B, Huang Y, Tang N, et al. Over-expression of a LEA gene in rice improves drought resistance under the field conditions[J]. Theoretical and Applied Genetics, 2007, 115(1): 35-46.