Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Tsukuba Plant-Innovation Research Center, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Plant Biotechnol J. 2019 Apr;17(4):801-811. doi: 10.1111/pbi.13016. Epub 2018 Oct 12.
The breeding of plantation forestry trees for the possible afforestation of marginal land would be one approach to addressing global warming issues. Here, we developed novel transgenic Eucalyptus trees (Eucalyptus camaldulensis Dehnh.) harbouring an RNA-Binding-Protein (McRBP) gene derived from a halophyte plant, common ice plant (Mesembryanthemum crystallinum L.). We conducted screened-house trials of the transgenic Eucalyptus using two different stringency salinity stress conditions to evaluate the plants' acute and chronic salt stress tolerances. Treatment with 400 mM NaCl, as the high-stringency salinity stress, resulted in soil electrical conductivity (EC) levels >20 mS/cm within 4 weeks. With the 400 mM NaCl treatment, >70% of the transgenic plants were intact, whereas >40% of the non-transgenic plants were withered. Treatment with 70 mM NaCl, as the moderate-stringency salinity stress, resulted in soil EC levels of approx. 9 mS/cm after 2 months, and these salinity levels were maintained for the next 4 months. All plants regardless of transgenic or non-transgenic status survived the 70 mM NaCl treatment, but after 6-month treatment the transgenic plants showed significantly higher growth and quantum yield of photosynthesis levels compared to the non-transgenic plants. In addition, the salt accumulation in the leaves of the transgenic plants was 30% lower than that of non-transgenic plants after 15-week moderate salt stress treatment. There results suggest that McRBP expression in the transgenic Eucalyptus enhances their salt tolerance both acutely and chronically.
种植人工林树木以可能绿化边缘土地将是应对全球变暖问题的一种方法。在这里，我们开发了新型转基因桉树（Eucalyptus camaldulensis Dehnh.），其携带源自盐生植物的 RNA 结合蛋白（McRBP）基因，普通冰草（Mesembryanthemum crystallinum L.）。我们使用两种不同的严格盐分胁迫条件对转基因桉树进行了筛选室试验，以评估植物的急性和慢性耐盐性。用 400 mM NaCl 处理（高严格盐分胁迫），在 4 周内导致土壤电导率（EC）水平>20 mS/cm。用 400 mM NaCl 处理时，>70%的转基因植物完好无损，而>40%的非转基因植物枯萎。用 70 mM NaCl 处理（中度严格盐分胁迫），2 个月后导致土壤 EC 水平约为 9 mS/cm，随后的 4 个月保持这些盐分水平。所有植物，无论转基因或非转基因状态，都能在 70 mM NaCl 处理下存活，但在 6 个月的处理后，转基因植物的生长和光合作用量子产量明显高于非转基因植物。此外，在 15 周中度盐胁迫处理后，转基因植物叶片中的盐分积累比非转基因植物低 30%。这些结果表明，McRBP 在转基因桉树中的表达增强了它们的急性和慢性耐盐性。
