Purified proteins, recombinant DNA sequences and processes for controlling the ripening of coffee plants

Coffee is prepared from the roasted beans of the plants of the genus Coffea, generally from the species (Caturra coffee) and (Robusta coffee), and hybrids of these. Beans are the seeds of the coffee plant and are obtained by processing the coffee fruit, ideally the mature coffee fruit which commands the best price due to its superior quality. In order to obtain high quality "gourmet" coffee, it was considered necessary in the past to pick the coffee tree fruit by hand because the fruits of a coffee tree do not ripen uniformly and, thus, there are both mature and immature fruit on the same tree. This did not previously present a serious problem, as most coffee is grown in areas of the world where labor is plentiful and not expensive. However, recently, a lack of abundant and inexpensive labor has become a major contributor to decreased coffee production. In order to increase productivity, countries in some regions of the world, such as the largest coffee producing country, Brazil, have resorted to strip harvesting where workers rapidly remove all fruit from a branch whether ripe or unripe. The speed of harvesting is thus increased, but the yield of the highest quality beans is decreased because much of the harvested fruit is immature (green). The invention establishes that coffee fruit ripening is climacteric. The invention further provides techniques to isolate substantially pure RNA from coffee fruit even though the fruit contains high levels of phenolic compounds and carbohydrate which would otherwise interfere with obtaining clean RNA preparations from this tissue. The invention provides purified proteins, nucleic acid sequences that code on expression therefore and recombinant DNA molecules, including hosts transformed therewith, and methods for transforming coffee plants to suppress the expression of coffee fruit-expressed ACC synthase and/or coffee fruit-expressed ACC oxidase necessary for ethylene biosynthesis and the ripening of coffee fruit. Coffee plants are transformed with vectors containing coffee fruit-expressed ACC synthase and/or with ACC oxidase DNA sequences that code on expression for the respective RNA that is antisense or sense to the mRNA for the respective ACC synthase and/or ACC oxidase. The result is that the expression of the respective enzyme is eliminated and the transformed plants are incapable of synthesizing ethylene during coffee fruit ripening, although other aspects of their metabolism is not affected. The invention furthe