University of Chinese Academy of Sciences, Beijing 100049, China; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
J Plant Physiol. 2018 Jul;226:31-39. doi: 10.1016/j.jplph.2018.04.005. Epub 2018 Apr 17.
Agronomic performance of transgenic tomato overexpressing functional genes has rarely been investigated in the field. In an attempt to improve low-phosphate (P) stress tolerance of tomato (Solanum lycopersicum) plants and promote tomato fruit production in the field, an expression vector containing cDNA to an Arabidopsis 14-3-3 protein, General Regulatory Factor 9 (GRF9), driven by a cauliflower mosaic virus 35S promoter, was transferred into tomato plants. Transgenic expression of GRF9 was ascertained by quantitative real-time PCR analysis. The degree of low-P tolerance in transgenic plants was found to be significantly greater than that in wild-type plants, and reflected in improved root development and enhanced P content under hydroponic conditions. For transgenic tomato, roots had higher P uptake, as evidenced by tissue P content and relative expression of the genes LePT1 and LePT2 in both normal and low-P hydroponic solutions. GRF9 overexpressors had greatly enhanced proton extrusion from roots and heightened activity of the plasma-membrane H-ATPase (PM H-ATPase) in roots under low-P hydroponic conditions. Thus, in addition to enhanced root development, higher expression of genes coding for phosphate transporters and improved capacity for acidification in the rhizosphere emerged as key mechanisms underpinning improved P acquisition in transgenic tomato plants in soil. Subsequent field trials measuring tomato fruit production at two P levels, indicated that GRF9 can indeed improve total tomato production and may play a role in early fruit maturity. Our results suggest that the heterologous Arabidopsis GRF9 gene can confer resistance to P deficiency in transgenic tomato plants and promote fruit production.
在田间条件下，很少有研究调查过转基因番茄过表达功能基因的农艺性能。为了提高番茄（Solanum lycopersicum）植株对低磷（P）胁迫的耐受性并促进田间番茄果实的生产，我们将含有拟南芥 14-3-3 蛋白基因 General Regulatory Factor 9（GRF9）的表达载体，该基因由花椰菜花叶病毒 35S 启动子驱动，转入番茄植株中。通过定量实时 PCR 分析证实了 GRF9 的转基因表达。发现转基因植株的低 P 耐性程度明显高于野生型植株，这反映在水培条件下根系发育改善和 P 含量增加。对于转基因番茄，根具有更高的 P 吸收能力，这表现在组织 P 含量和正常和低 P 水培溶液中 LePT1 和 LePT2 基因的相对表达上。在低 P 水培条件下，GRF9 过表达植株的根中质子外排显著增强，质膜 H+-ATP 酶（PM H+-ATPase）活性升高。因此，除了增强根系发育外，提高编码磷酸盐转运体的基因的表达和改善根际酸化能力成为了在土壤中提高转基因番茄植株 P 吸收的关键机制。随后的田间试验在两个 P 水平下测量番茄果实的产量，表明 GRF9 确实可以提高番茄的总产量，并可能在早期果实成熟中发挥作用。我们的结果表明，异源拟南芥 GRF9 基因可以赋予转基因番茄植株对 P 缺乏的抗性，并促进果实的生产。
