Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/16/2005
Publication Date: 7/16/2005
Citation: Radmer, L., Garvin, D.F., Somers, D., Samac, D.A. 2005. Characterization of transgenic oat plants for enhanced aluminum tolerance via expression of an alfalfa MDH gene [abstract]. Plant Biology Annual Meeting. Abstract No. 512.
Technical Abstract: Aluminum (Al) toxicity is a large problem in acid soils all over the world. When the soil is at a low pH (i.e.: below 5.5), aluminum is in its most soluble form, Al3+. In this form, Al is able to enter the root tip and stunt root growth. One Al tolerance mechanism is the secretion of organic acids such as malate and citrate from plant roots. Organic acids chelate the Al ion and prevent it from damaging cells. In alfalfa, a novel nodule-enhanced malate dehydrogenase (neMDH) that converts oxaloacetate into malate was identified and the gene sequenced. The rate of conversion of oxaloacetate by neMDH is 30-fold faster than for the cytosolic form of MDH. In efforts to enhance aluminum tolerance in small grain crops, transgenic oat plants with neMDH controlled by the sugarcane bacilliform virus promoter were produced. T2 seedlings from 42 lines were tested by RT-PCR to identify 3 lines homozygous for the transgene. Western blots using protein extracted from roots and leaves show that these plants express neMDH. Al tolerance of these plants will be tested in hydroponic assays and the amount of malate secreted by these transgenic plants will also be measured.