Biotechnology Research Center, The University of Tokyo Tokyo, Japan ; Graduate School of Agricultural and Life Sciences, The University of Tokyo Tokyo, Japan.
Biotechnology Research Center, The University of Tokyo Tokyo, Japan.
Front Plant Sci. 2014 Apr 1;5:125. doi: 10.3389/fpls.2014.00125. eCollection 2014.
Nutrient deficiency in soil poses a widespread agricultural problem. Boron (B) is an essential micronutrient in plants, and its deficiency causes defects in both vegetative and reproductive growth in various crops in the field. In Arabidopsis thaliana, increased expression of a major borate transporter gene AtBOR1 or boric acid channel gene AtNIP5;1 improves plant growth under B-deficient conditions. In this study, we examined whether high expression of a borate transporter gene increases B accumulation in shoots and improves the growth of tomato plant, a model of fruit-bearing crops, under B-deficient conditions. We established three independent transgenic tomato plants lines expressing AtBOR1 using Agrobacterium-mediated transformation of tomato (Solanum lycopersicum L. cv. Micro-Tom). Reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed that two lines (Line 1 and Line 2) more strongly expressed AtBOR1 than Line 3. Wild-type plants and the transgenic plants were grown hydroponically under B-sufficient and B-deficient conditions. Wild-type and Line 3 (weakly expressing transgenic line) showed a defect in shoot growth under B-deficient conditions, especially in the development of new leaves. However, seedlings of Line 1 and Line 2, the transgenic lines showing strong AtBOR1 expression, did not show the B-deficiency phenotype in newly developing leaves. In agreement with this phenotype, shoot biomass under low-B conditions was higher in the strongly expressing AtBOR1 line. B concentrations in leaves or fruits were also higher in Line 2 and Line 1. The present study demonstrates that strong expression of AtBOR1 improved growth in tomato under B-deficient conditions.
土壤养分缺乏是一个广泛存在的农业问题。硼（B）是植物必需的微量元素，其缺乏会导致田间各种作物的营养生长和生殖生长缺陷。在拟南芥中，硼酸转运体基因 AtBOR1 或硼酸通道基因 AtNIP5;1 的表达增加，可改善 B 缺乏条件下植物的生长。在这项研究中，我们研究了高表达硼酸转运体基因是否会增加 shoot 中的 B 积累，并改善 B 缺乏条件下番茄（Solanum lycopersicum L. cv. Micro-Tom）这种果实类作物模型的植物生长。我们使用农杆菌介导的转化方法将 AtBOR1 转入番茄（Solanum lycopersicum L. cv. Micro-Tom），建立了三个独立的 AtBOR1 转基因番茄株系。反转录聚合酶链式反应（RT-PCR）分析证实，Line 1 和 Line 2 比 Line 3 更强烈地表达 AtBOR1。在 B 充足和 B 缺乏条件下，将野生型植株和转基因植株进行水培。在 B 缺乏条件下，野生型和 Line 3（弱表达的转基因系）植株的 shoot 生长出现缺陷，特别是新叶的发育。然而，强表达 AtBOR1 的 Line 1 和 Line 2 的转基因系幼苗在新发育的叶片中没有表现出 B 缺乏表型。与这种表型一致，在低 B 条件下，强表达 AtBOR1 系的 shoot 生物量更高。叶片或果实中的 B 浓度在 Line 2 和 Line 1 中也更高。本研究表明，AtBOR1 的强表达改善了番茄在 B 缺乏条件下的生长。
