- Two types of full-length cDNA of OsPIN3a were identified in the database. The second exon of the longer full-length cDNA of OsPIN3a, whose exon–intron structure was similar to that of OsPIN3b and OsPIN1 genes, was divided into two exons by an intron in the shorter full-length cDNA.
- The phytohormone auxin plays a critical role in plant growth and development, and its spatial distribution largely depends on the polar localization of the PIN-FORMED (PIN) auxin efflux carrier family members.
- As a putative auxin efflux carrier gene in rice, OsPIN3t acts in auxin polar transport but is also involved in the drought stress response in rice, which suggests that a polar auxin transport pathway is involved in the regulation of the response to water stress in plants.
- Bioinformatics studies suggest that OsPIN3t was presumed to be an auxin efflux carrier and a member of the PIN family. The OsPIN3t cDNA and genomic sequences comprise 1857 and 4307 nucleotides, respectively. The UniProtKB/Swiss-Prot database suggested that OsPIN3t has two isoforms that are produced by alternative splicingref name="ref3"/>.
GO assignment(s): GO:0005554,GO:0016021
- OsPIN3tpro::GUS rice lines:
- GUS activity increased strikingly with NAA treatment and decreased significantly with NPA treatment.
- The GUS staining in the coleoptile of OsPIN3tpro::GUS rice lines strongly increased after treatment with 50 nM NAA and decreased distinctly after treatment with 10 lM NPA. Similar results were observed in Arabidopsis by another group (Tsuda et al.,2011), which provides evidences that OsPIN3t is directly induced in response to auxin.
- Homozygous OE
- Their seeds were germinated in MS medium or MS medium supplemented with 5 lM NPA. After 5 days, more adventitious crown roots emerged from the WT and OE stems in MS medium, and fewer crown roots emerged from the plants subjected to NPA treatmentref name="ref3"/>.
- Different expression levels were also found between OsPIN10a and OsPIN10b. OsPIN10a was highly expressed in all of the tested tissues, except for in root, while relatively high expression was only found in leaf for OsPIN10b. OsPIN3a was expressed in leaf, shoot apex, panicle and callus, but no expression was detected in root.
- In flower organs, OsPIN1a and OsPIN1c, OsPIN5b and OsPIN10b were expressed in both vein of hull and anther; OsPIN5a, OsPIN5b, and OsPIN10a were expressed in anther, and OsPIN1b and OsPIN2 in vein of hull. OsPIN1b and OsPIN10a were also expressed in stigma. OsPIN2, OsPIN3a and OsPIN5a also showed slightly higher expression in an outermost cell layer.
- For OsPIN10, high expression of OsPIN10a was found in vascular tissues and relative low expression in pericycle cells and stele. Weak expression of OsPIN10b was observed in pericycle cells. The tissue-specific expression patterns of OsPIN3t were also investigated using a b-glucuronidase(GUS) reporter, which showed that OsPIN3t was mainly expressed in vascular tissue. The GUS activity in OsPIN3tpro::GUS plants increased by NAA treatment and decreased by NPA treatment.
- OsPIN1c, OsPIN5a, OsPIN10a, and OsPIN10b were induced by JA. OsPIN5b, OsPIN9, OsPIN10a, and OsPIN10b were induced by 6-BA. Knockdown of OsPIN3t caused crown root abnormalities in the seedling stage that could be phenocopied by treatment of wild-type plants with NPA, which indicated that OsPIN3t is involved in the control of polar auxin transport. Overexpression of OsPIN3t led to improved drought tolerance, and GUS activity significantly increased when OsPIN3tpro::GUS plants were subjected to 20% polyethylene glycol stress.
OsPIN3t–GFP fusion proteins are localized in plasma membranes, and this subcellular localization changes under 1-N-naphthylphthalamic acid (NPA) treatment.
- Four OsPINs(designated as OsPIN1a–d) were clustered with AtPIN1, while the previously reported OsPIN4 clustered with AtPIN3, 4, and 7 was not found (Figure 1A). Two new members of the PIN family, one centered to PIN5 (OsPIN5c) and one paired with AtPIN8 (OsPIN8), were also found (Figure 1A).
- Hydropathy analyses of the OsPIN3t amino acid sequence showed that the protein contains three characteristic regions including two mem_trans superfamilies, five hydrophobic stretches in the N-terminus, a predominantly hydrophilic core, and a hydrophobic region with five transmembrane segments, which showed similarity to OsPIN1b, and these domains are found in all PIN and PIN-like proteins.
- The OsPIN3t protein shares 63% sequence identity with AtPIN3 and 61% sequence identity with AtPIN4.
- Auxin is synthesized primarily in meristematic regions at the shoot apex and transported in a polar fashion to the root tip. An auxin signaling distal maximum and gradients in Arabidopsis root are recognized to be fundamental to cell fate and patterned root development.
- PIN proteins as efflux carriers of auxin mediate auxin acropetal flow to root tip through the central vasculature and basipetal flow through the epidermis.
Labs working on this gene
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zi Jin Gang Campus, Zhejiang University, Hangzhou, 310058, People’s Republic of China
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, Hebei 050024, China
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, Zhejiang 310006, China
- Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
- Wang J R, Hu H, Wang G H, et al. Expression of PIN genes in rice (Oryza sativa L.): tissue specificity and regulation by hormones[J]. Molecular plant, 2009, 2(4): 823-831.
- Miyashita Y, Takasugi T, Ito Y. Identification and expression analysis of PIN genes in rice[J]. Plant science, 2010, 178(5): 424-428.
- Zhang Q, Li J, Zhang W, et al. The putative auxin efflux carrier OsPIN3t is involved in the drought stress response and drought tolerance[J]. The Plant Journal, 2012, 72(5): 805-816.
- Sabatini S, Beis D, Wolkenfelt H, et al. An auxin-dependent distal organizer of pattern and polarity in the Arabidopsis root[J]. Cell, 1999, 99(5): 463-472.
- Friml J, Vieten A, Sauer M, et al. Efflux-dependent auxin gradients establish the apical–basal axis of Arabidopsis[J]. Nature, 2003, 426(6963): 147-153.
- Rashotte A M, Brady S R, Reed R C, et al. Basipetal auxin transport is required for gravitropism in roots of Arabidopsis[J]. Plant Physiology, 2000, 122(2): 481-490.