However, the growth of perennial ryegrass as turfgrass is hampered by the aggravation of soil salinization and the shortage of water resources. It is widely cultivated as a turfgrass and forage with favorable agronomic traits, including rapid establishment rate, strong tiller ability, strong trample resistance, as well as high yield 3. Perennial ryegrass ( Lolium perenne L.) is an important cool-season grass in temperate regions worldwide. Salinity stress has become one of the major abiotic factors that severely affects plant growth. The area of saline land worldwide is nearly 1 billion hectares, and accounts for 10 percent of the total land area 1, 2. To our best knowledge this study is the first report of utilizing Chimeric Repressor gene-Silencing Technology (CRES-T) in turfgrass and forage species for salt-tolerance improvement. Physiological analyses including relative leaf water content, electrolyte leakage, proline content, malondialdehyde (MDA) content, H 2O 2 content and sodium and potassium accumulation indicated that the OsDST-SRDX fusion gene enhanced salt tolerance in transgenic perennial ryegrass by altering a wide range of physiological responses. Transgenic lines overexpressing the OsDST-SRDX fusion gene showed obvious phenotypic differences and clear resistance to salt-shock and to continuous salt stresses compared to non-transgenic plants. Integration and expression of the OsDST-SRDX in transgenic plants were tested by PCR and RT-PCR, respectively. Here, the rice DST gene was linked to an SRDX domain for gene expression repression based on the Chimeric REpressor gene-Silencing Technology (CRES-T) to make a chimeric gene ( OsDST-SRDX) construct and introduced into perennial ryegrass by Agrobacterium-mediated transformation. Phylogenetic analysis of six homologues of DST genes in different plant species revealed that DST genes were conserved evolutionarily. Any queries (other than missing content) should be directed to the corresponding author for the article.The Drought and Salt Tolerance gene ( DST) encodes a C 2H 2 zinc finger transcription factor, which negatively regulates salt tolerance in rice ( Oryza sativa). Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Tpj1277-legends.docxWord document, 18.6 KB Tpj1277-TableS7.pdfPDF document, 143.9 KB Primers used for quantitative real-time RT-PCR experiments. Primers used for the overexpression constructs. Primers used for the effector constructs. Primers used for the reporter constructs. Primers used for genotyping myc5 mutant plants. Tpj1277-TableS1.pdfPDF document, 160.9 KB Phenotypic characterization of MYC5-OE plants. JA-mediated root growth inhibition assay for MYC-SRDX plants.įigure S9. JA-mediated root growth inhibition assay for various MYC5-SRDX lines.įigure S8. Repression of JA responses in MYC5-SRDX plants and carrot protoplasts.įigure S7. Phenotypic characterization of MYC5-SRDX flowers.įigure S6. Phenotypic characterization of myc5 null-mutant plants.įigure S5. Arabidopsis MYC5::GUS plants stained for GUS activity.įigure S4. Subcellular localization of MYC5 protein.įigure S3. Taken together, these results indicate that MYC5, probably together with other, redundant transcription factors, may be activated by JA signaling to induce the expression of MYB21 and components required for male fertility.įigure S2. Importantly, expression of MYB21 and other transcription factors required for stamen and pollen maturation was strongly reduced in stamens of MYC5-SRDX plants relative to the wild type.
In particular, MYC5-SRDX plants were male-sterile, with defects in stamen filament elongation, anther dehiscence and pollen viability. Two allelic myc5 mutants exhibited no overt phenotype however, transgenic lines expressing MYC5 fused to an SRDX (SUPERMAN repressive domain X) motif phenocopied mutants defective in JA signaling. A G-box sequence in the JAZ2 promoter was necessary and sufficient for induction by MYC5 (as it is for MYC2, MYC3 and MYC4), and induction of JAZ genes was repressed by co-expression of a stabilized, JAZ1ΔJas repressor.
We found that a closely related transcription factor, MYC5 (bHLH28), was able to induce JAZ promoters that control some of the early JA-responsive genes in a Daucus carota (carrot) protoplast expression system. MYC2, MYC3 and MYC4 are JAZ-interacting bHLH transcription factors that play a major role in controlling JA responses in vegetative tissue, but are not likely to play a role in reproductive tissue. Arabidopsis thaliana plants deficient in JA-biosynthesis or -signaling are male-sterile, with defects in stamen and pollen development. Jasmonate hormone (JA) plays critical roles in both plant defense and reproductive development.
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