Effect of cell wall protein in fruit

Scientists at the University of California, Davis studying tomatoes discovered two plant enzymes in the cell walls of the plants that combine to make ripe tomatoes more susceptible to disease-causing fungi. .

Ann Powell, a plant scientist who directed the study, said: 'It is important to determine the role of two cell-walled enzymes in making fruits that are susceptible to finding the methods. limit broken fruits during storage, purchase and distribution '. The research results are published in the issue of January 22, 2008 in the Proceedings of the National Academy of Sciences.

One of the distinguishing characteristics of plant cells is the very hard outer cell wall. When the fruit ripens, the cell wall breaks, so the fruit becomes softer and smells better. At the same time, they easily caught the diseases caused by fungi and bacteria.

Scientists have discovered that two enzymes called polygalacturonase and expansin are also involved in the breakdown of cell membranes when ripe fruits (enzymes are proteins that catalyze and control chemical reactions). The University of California, Davis team also suspects that the two enzymes in the cell walls also contribute to increased susceptibility to ripe fruit. Diseases can significantly reduce the quality of harvested fruit during storage, shipping by ship, advertising and buying.

Botrytis cinerea mushroom causes rot fruit and vegetables (Photo: Mobot.org)

To test the hypothesis, researchers collected two genetically modified tomatoes. One variety has been modified to not produce polygalacturonase, while the other cannot produce expansin. Mrs. Powell has bred together to create a new variety that cannot produce both of these enzymes.

The team includes Dario Cantu, a botanical student and Ariel Vicente, postdoctoral, who implanted Botrytis cinerea into two genetically modified plants and their crosses. This is a common fungus that causes fruit and vegetables to rot. Tomato plants from the original varieties that are not modified by enzyme production are also implanted with Botrytis fungi.

They found that tomatoes from genetically modified varieties could not produce just one of the two enzymes that did not reduce the likelihood of fungal attacks. But when both enzymes are not produced in the offspring, the cell walls of this tomato variety are not easily broken . Fruit also significantly increased resistance to Botrytis cinerea.

Powell said: 'It seems that these two enzymes work together to break down the cell wall, making it vulnerable to pathogens, such as gray mold, caused by the fungus.'

'Interestingly, this process occurs during the developmental stage of the plant, causing both the plant and the disease to reproduce. Accuracy of convenient and useful time for both can be the result of co-evolution between fruit and the corresponding diseases. "

Research collaboration with Ms. Powell, Cantu and Vicente also includes professional researchers: Molly Dewey - formerly of the University of California, Davis and Oxford University; Carl Greve, professor of botany John Labavitch and Alan Bennett.