Abstract
Oxidizing agents are a normal product of aerobic metabolism and may also be encountered from environmental sources. Aluminum is one proposed source of environmental oxidative stress in plants, and is a major component of soils and an inhibitor of plant growth. Plant cells have evolved universal mechanisms to mediate oxidative stress including the enzyme glutaredoxin, which utilizes a disulfide oxidation-reduction mechanism to detoxify free radicals. A preliminary study suggested that the soybean glutaredoxin gene is expressed preferentially in roots and stems of soybean seedlings in response to toxic levels of Al in soils. To expand our understanding of our initial results, we examined the roots, stems, and leaves of soybean seedlings grown in soil treated with 0, 20, and 50 mM AlCl3 and for periods of 10, 20, or 30 days. We also attempted to more precisely quantitate the differential soybean glutaredoxin response within the plant tissues by adding an 18s rRNA internal control to the RT-PCR amplification reaction. The preliminary results proved inconclusive as 18s gene transcript amplification was inconsistent and glutaredoxin gene amplification was seen only in roots and leaves at 20 days. In the future the RT-PCR reaction needs to be optimized and the experiments repeated, as the results of this preliminary study did not negate the validity of our assumptions.