ORE7 유전자 도입에 의한 노화지연 크리핑 벤트그라스 개발

Abstract

The ORE7 gene has been known to delay the characteristics of leaf senescence in age-dependent manner in Arabidopsis thaliana. To develop the bentgrass with the extended longevity in its leaf organ, we introduced the ORE7 gene with ubiquitin promoter along with the herbicide resistance (bar) gene into the creeping bentgrass (Agrositis stolonifera L. cv. "Penncross") using pCAMBIA3301 vector. The transgenic plants were selected on the media with 5 mg/L Phosphinothricin (PPT) and identified the insertion of gene by the PCR analysis. In the immunoassay of bar gene product from the selected lines, phosphinothricin acetyltransferase (PAT) protein was easily identified in all plants tested. Southern blotting was performed; clearly one mutant line (ORE7-1) with a single copy and the other mutant lines (ORE7-2 and ORE7-3) with two copies, respectively. We then compared the characteristics of leaf senescence using chlorophyll degradation pattern, chlorophyll content, photochemical efficiency (Fv/Fm) from the transgenic lines under dark treatment. During wild-type was under severe stress at 4-day and completely at 10-day in continuous dark treatment, the ORE7-1 (ORE7-ox) was comparably delayed in chlorophyll content. Photochemical efficiency further supported that the ORE7-1 (ORE7-ox) showed still a 90% activity in the same conditions. We also compared the phenotype of leaf senescence between the wild-type and the ORE7-1 (ORE7-ox) transgenic plants under the salt stress; wild-type plant completely was stressed more than 100 mM NaCl at 6-day treatment, whereas the ORE7-1 (ORE7-ox) was slightly affected. The results suggest that the transgenic bentgrass plants were extended the leaf longevity by the introduction of ORE7 gene and well tolerated both in dark and salt stresses.