Os11g0446000
RSS3(rice salt sensitive 3) is a rice nuclear factor,that regulates root cell elongation during adaptation to salinity.
Contents
Annotated Information
Function
RSS3(rice salt sensitive 3), has a regulatory role in root cell elongation. RSS3 interacts not only with JAZs, but also with non-R/B-like bHLH transcription factors and forms an RSS3-JAZ-bHLH ternary complex in the nucleus. Loss of function of RSS3 activates the expression of a subset of JA-induced genes in the root apex and restricts cell elongation but does not primarily affect cell division activity. Under high-salinity conditions, rss3 mutants exhibit severely inhibited root growth, concomitant with root cell swelling[1].Loss of function of RSS3 only moderately inhibits cell elongation under normal conditions, but it provokes spontaneous root cell swelling, accompanied by severe root growth inhibition, under saline conditions. RSS3 and bHLH094 can interact in plant cells.Among more than 150 bHLH factors in rice, bHLH094 belongs to the class-C group. The distinguishing feature of class-C members is the conservation of bHLH sequences and the subsequent C-terminal regions.RSS3 can specifically interact with bHLH094 and bHLH089,but not with bHLH092.bHLH089 is classified in the same minor clade that bHLH094 belongs to.Interestingly, both full-length bHLH094 and bHLH089 lack the N-terminal regulatory domains that are conserved among R/B-like bHLH factors and RSS3. The genes encoding bHLH094 and bHLH089 were expressed in the root tip, so RSS3 acts as a regulatory module for bHLH094 and bHLH089 and thus is directly involved in transcriptional regulation in the root tip. As described above, RSS3, but not bHLH094 or bHLH089, contains the regulatory domain conserved among R/B-like bHLH transcription factors. Considering that region II of the regulatory domain is a part of the JAZ interacting domain, so RSS3 is capable of binding to JAZ proteins. RSS3 forms a ternary complex with rice bHLH094 and JAZ9,and RSS3 and JAZ together repress bHLH094-mediated transcriptional activation.
Mutant
In the course of a genetic screen of rice to identify loci responsible for salt tolerance, we identified a recessive mutant designated rss3. When grown under high-salinity conditions, rss3 exhibited severely impaired root growth compared with the wild type. Root growth in the absence of salinity stress was also inhibited in rss3, but only moderately. The length of cells in the MTZ of roots of rss3 plants grown under unstressed conditions was markedly shorter than those of the wild type. The inhibition of root growth in rss3 appeared to be primarily due to reduced cell elongation because the size of the EZ, but not of the MZ, was reduced in the mutant, and the number of cells in both the EZ and MZ was not affected in the mutant. The exaggerated inhibition of root growth under salinity conditions also appeared to be mainly due to compromised cell elongation but was accompanied by aberrant cellular arrangement and the formation of oblique cell plates in the MZ, swelling of the cells in the EZ, and a waviness of the root surface at the MTZ. Moreover, rss3 roots show impaired flexibility, in a salinity-dependent manner. When extracted from the medium, the wild-type roots exhibited a paintbrush-like shape, but rss3 roots did not, due to stiffness[1].
Expression
RSS3 Encodes a Nuclear Protein Homologous to the Regulatory Domain of the R/B-Like bHLH Transcription Factors.RSS3 encodes a protein consisting of 458 amino acids. RSS3 contains a region homologous to the postulated regulatory domain conserved among the R/B-like bHLH transcription factors, which contains four conserved regions (I to IV). Region II is predicted to constitute the central sequence of the JAZ interacting domain. However, RSS3 does not contain a bHLH domain or another known DNA binding motif. rss3 contains a 47-bp deletion at the junction between the 6th intron and 7th exon , which results in an altered splicing pattern and the production of a mutated protein that lacks 15 amino acids in region IV and six amino acids in the subsequent C-terminal nonconserved region. In seedlings, RSS3 was expressed predominantly in the roots, particularly in the root tip. A truncated form of RSS3 transcript was expressed in the mutant roots, at levels that were apparently higher than those of the nondeleted RSS3 transcript in the wild type. When enhanced green fluorescent protein (EGFP)–tagged RSS3 was expressed under the control of the RSS3 promoter, EGFP signals were detected at high levels in the MZ and at low levels in the EZ of the root tip. The fusion protein was localized almost exclusively in the nuclei of the MZ cells. By contrast, nonfused EGFP expressed under the control of the constitutive actin gene promoter was localized in both nuclei and the cytoplasm of MZ cells. In the EZ region bordering the MZ, RSS3-EGFP was detected in both the nucleus and the cytoplasm[1].
Evolution
Please input evolution information here.
Labs working on this gene
- Bioscience and Biotechnology Center, Nagoya University, Chikusa, Nagoya 464-8601, Japan
- National Institute of Agrobiological Sciences, Kannondai, Tsukuba 305-8602, Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8562, Japan
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Yosuke Toda;Maiko Tanaka;Daisuke Ogawa;Kyo Kurata;Ken-ichi Kurotani;Yoshiki Habu;Tsuyu Ando;Kazuhiko Sugimoto;Nobutaka Mitsuda;Etsuko Katoh;Kiyomi Abe;Akio Miyao;Hirohiko Hirochika;Tsukaho Hattori;Shin Takeda. RICE SALT SENSITIVE3 Forms a Ternary Complex with JAZ and Class-C bHLH Factors and Regulates Jasmonate-Induced Gene Expression and Root Cell Elongation. The Plant Cell, 2013, 25(5): 1709-1725.
- ↑ Godoy M., Franco-Zorrilla J.M., Pérez-Pérez J., Oliveros J.C., Lorenzo Ó., Solano R.Improved protein-binding microarrays for the identification of DNA-binding specificities of transcription factors. Plant J.2011, 66: 700–711.
