Word: frosted
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...Frostban marked still another in a series of frustrating delays. As long ago as 1982, the company began partly financing the research efforts of Steven Lindow and Nickolas Panopoulos, plant pathologists at the University of California, Berkeley, who were attempting to engineer bacteria that would inhibit the formation of frost on plants. Their long-range goals: to extend the growing season and reduce crop damage caused by unseasonal frosts, which costs U.S. farmers at least $1.5 billion every year...
...Berkeley team had focused its efforts on the bacterium Pseudomonas syringae, which lives on the leaves of many plants and actually promotes the formation of frost. As the temperature drops below 32 degrees F, specks of protein produced by the bacteria act as nuclei for the growth of ice crystals (see chart). Without the bacteria and their protein particles, plants can briefly sustain temperatures as low as 25 degrees F before the dew turns to frost. The solution seemed simple enough: from 2% to 5% of the bacteria in nature lack the ability to manufacture the protein. If large numbers...
...Panopoulos proceeded to expose large numbers of P. syringae to chemicals, and were able to impair in some of them the gene that orders production of the protein. When these altered microbes were sprayed on plants in greenhouses and open fields, they seemed to retard the formation of frost. Equally important, they apparently did not spread or do any harm, and most gradually died out. Their release into the open went unnoticed--or at least unchallenged--because they had been altered by conventional laboratory methods...
Still, the Berkeley team was not satisfied with its hit-and-miss method of creating frost-inhibiting bacteria, and set about producing them by gene- splicing techniques. For meaningful experiments, enough of the bacteria had to be sprayed on test plants to overwhelm the natural variety. But the release into the environment of any genetically engineered microbes in those days required the nod of the National Institutes of Health recombinant-DNA committee,* which in 1983 approved the Berkeley scientists' proposal to conduct their test at a tiny potato patch near the city of Tulelake in Northern California...
...They warned that re-engineered P. syringae might also cause trouble. For example, they said, the altered bacteria might multiply and spread, perhaps even change the climate by retarding the formation of ice crystals in the atmosphere. Lindow and Panopoulos undermined that argument by pointing out that naturally occurring frost-inhibiting bacteria show no such inclination...