Closing the Gap Between Growth and Consumption of Edible Stuff

The process of ripening holds key to prosperity of farmers and benefits the consumer. A new discovery shows that chloroplasts are affected by the ubiquitin proteasome system (UPS).

Professor Douglas Kell, Chief Executive of BBSRC (a bioscience research body of UK), said: "To ensure that we have enough healthy, sustainable food for a growing population, we need to find a range of novel solutions to challenges such as improving crop yields and reducing food waste. This research highlights one of the many ways in which science can help.

"The ripening process can happen quickly, and it can take just a few days for a fruit or vegetable to be considered inedible. This unavoidable process means big losses to both farmers and consumers. This discovery brings us one step closer to greater control over ripening so that we have greater flexibility for farmers when supplying produces in the best condition."

This process is responsible for the breakdown of unwanted proteins in cells that is thought to only act on central parts of the cell.

The researchers believe that with the help of specific proteins such as conversion of chloroplasts into highly-pigmented chloroplasts during the ripening of fruit, they can regulate the function of the chloroplast.

In this paper the scientists identify a gene (SP1) in the nuclei of plant cells that codes for a protein called a ubiquitin E3 ligase which is able to regulate chloroplast development through the UPS process.

The team has already engaged in investigating the potential for harnessing the SP1 gene in different crop plants such as tomatoes, bell, peppers and citrus.

The project was led by Professor Paul Jarvis, of the University's Department of Biology.

He said: "Our work shows that the UPS also acts on subcellular compartments in plant cells called chloroplasts, which are responsible for the light-driven reactions of photosynthesis that power almost all life on Earth.

"Identification of this previously-unsuspected link between the UPS and chloroplasts constitutes a major breakthrough in biology, and may enable the manipulation of chloroplast functions in crops.

"It is incredible to get to this point -- it has been a long journey. We have known for some time that this was going to be a big breakthrough."

 Their paper, Choroplast Biogenesis is Regulated by Direct Action of the Ubiquitin-Proteasome System, is due to be published in the journal Science on Nov 2.