Invasiveness, allelopathic potential and unintended effects of miraculin transgenic tomato to soil microbes

Tomato cv. Moneymaker was modified by the insertion of a miraculin gene, which can modify a sour taste into a sweet taste. Environmental safety assessment for this special transgenic crop is an important step in assessing how safe this tomato is before it is released into the environment. Evaluation of invasiveness, allelopathy and unintended effects is highly essential for environmental safety assessment. The evaluation of invasiveness was carried out by growing a mixture of transgenic and non-transgenic tomatoes with ratios of 0:100 and 100:0 (sole-cultivation) and 25:75, 50:50 and 75:25 (mix-cultivation). Wet and dry biomasses of three-week-old tomato plants were measured. Soil microbes were evaluated by determining microbial populations (culturable) and estimating soil respiration. Microbial populations were determined through total plate count, while soil respiration was estimated using the titration method to calculate the levels of carbon dioxide released during the incubation. It was found that the aggressiveness of the miraculin transgenic tomato was equal to that of its counterpart. There were also no significant differences in microbial populations and soil respiration of miraculin transgenic tomato compared with those of wild type. In addition, miraculin transgenic tomato did not produce allelopathy that interfered with surrounding crops. It is concluded that transgenic tomato is equal to its counterpart in invasiveness, with no effect to soil microbes and no potential allelopathy found.