The scientists repeated the process for gene C, and thus ended up with two types of plasmid. Each genetically engineered plasmid was introduced into individual thale cress plants. They cross-fertilized the two different lines. The offspring of this cross breeding produced microscopic PHB granules in every cell, proof that all three genes were now working, built-in parts of the plants. It sounds wonderful, but the work to date only amounts to a good start.
Several problems remain.
First, the plastic-producing plants were stunted, either as a result of a toxic effect from the plastic or as a result of the redirection of energy to plastic production instead of plant growth. Second, because the plastic was produced in small quantities in every cell, it was not easily obtained. The next step is to encourage plastic production in a harvestable portion of the plant, such as seeds. Finally, approval for sowing genetically engineered crops outside the laboratory needs to be gained, probably the biggest hurdle. The research team predicts all these snags can be ironed out within the next 10 years.