University of Hawaii System newsletter

Controlling Ripening Fruit

Posted on | October 30, 2009 | Comments Off on Controlling Ripening Fruit

Plant Physiology cover

Mānoa Professor David Christopher, Research Support Kristie Matsumoto and Leon Neuteboom developed a new process for the control of protein degradation in ripening pineapple fruit. They applied an arsenal of state-of-the-art methods, including proteomics, electron microscopy, molecular and cellular biology and biochemistry, to decipher the biochemical processes that underpin fruit ripening. The research was published in Plant Physiology and was featured on the journal’s cover.

Ripening of pineapple fruit is an important process determining when fruit will be harvested, its ability to withstand shipping, and the length of its shelf life. Ripening triggers the creation and activation of enzymes that chew away at cell walls and proteins, softening the fruit. One of the most obvious changes is the degradation and loss of the green pigment chlorophyll.

The group discovered a novel potent inhibitor of cell death proteases and determined how the inhibitor is turned on and off. Living cells, including those of plants, contain proteins that control many functions. Some proteins are “turned on” only at a certain developmental stage (such as ripening) or in response to an environmental cue. At other times, these proteins are “turned off.” The research team found a unique region of the inhibitor—found only in pineapple—that is essential for inhibition. When this region of amino acids are removed, the inhibitor becomes inactive, is turned off, leading to protein degradation and cell death.

“This research furthers our understanding of the processes that trigger of protein degradation in all cells,” says Christopher. “Many of the features of ripening are akin to onset of aging, leading to the death of cells not just in plants but in mammals as well.”

Read the news release.