Blossom end rot: transport protein identified

Blossom end rot on tomatoes
(picture: Agroscope)

Poor calcium distribution in agricultural crops causes substantial loss of income every year. Now a Korean-Swiss research team under the co-leadership of plant physiologists at the University of Zurich identified a protein that regulates calcium transport in the plant root and up to the shoot. For plant breeding, the specific transport protein provides a first step toward correcting deficiency symptoms in food plants.

Blossom end rot on tomatoes and cucumbers, spotty apples – these unpleasant blemishes on fruits and vegetables not only compromises the flavor but also causes significant harvest losses every year. The characteristic blotches and spotting can be traced back to insufficient calcium uptake or faulty calcium transport within the plant. Consequently, the damage can occur even if the soil provides sufficient calcium. A team under the leadership of scientists from the University of Zurich and Pohang University of Science and Technology, Korea, has for the first time identified a protein which is responsible for the calcium transport from the root to the shoot. "Without this transport protein, plants exhibit stunted growth," explains Enrico Martinoia, Professor for Molecular Plant Physiology at the University of Zurich.

Read full press release: University of Zurich

UGA discovery changes how scientists think about plant cell wall formation

Implications for biofuels

Athens, Ga. – University of Georgia researchers have discovered that two proteins come together in an unexpected way to make a carbohydrate, a chain of sugar molecules, in plant cell walls. This fundamental discovery changes the way scientists think about how plant cell walls are made and opens a new door to converting plants to biofuels and other carbon-based products.

In 2006, the UGA research team, led by Debra Mohnen, a faculty member in the UGA Complex Carbohydrate Research Center, discovered GAUT1, the first protein shown to synthesize pectin, a major component of the plant cell wall. Now Mohnen's team has shown that GAUT1 and a genetically similar protein called GAUT7, which does not appear to have pectin-synthesizing activity by itself, form a critical part of a pectin-synthesizing protein complex.

Moreover, the two-protein complex may serve as a "core" complex that associates with additional pectin-synthesizing proteins to form still larger carbohydrate-synthesizing complexes in the plant cells.

The findings signify a "critical step in changing our view of how the plant cell wall is made," said principal investigator Mohnen, a professor of biochemistry and molecular biology in the UGA Franklin College of Arts and Sciences. The study was published this week in the Proceedings of the National Academy of Sciences.

Plant proteins block invading microbes

DAVIS, Calif., July 7 (UPI) -- U.S. and Danish scientists say they've identified proteins that prevent bacteria from infecting a plant's leaves.

The researchers at the University of Copenhagen, the University of California-Davis and UC-Berkeley said identifying the proteins will likely find application in better protecting agricultural crops and horticultural plants against diseases.

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Understanding nature's role in a biofuel future

June 16, 2009

A US-Dutch collaboration has advanced the science of turning crops into energy. The EU-funded research, published in Nature Cell Biology, has added to the field of knowledge on cellulose, the molecule that plant cell walls are made from and the key to producing the energy-rich crops of the future.

The work, produced by scientists at the Wageningen University in the Netherlands and the Carnegie Institution for Science in the US, was funded in part by the 'New and Emerging Science and Technology' (NEST) activity of the European Union's Sixth Framework Programme (FP6).

Science's understanding of cellulose, how it forms and its underlying processes, is rather limited. Nevertheless, its potential to help develop renewable, plant-based biofuels is enormous. It is for this reason that the US-Dutch team targeted the fibrous molecule in their research, to bring research one step closer to new sources of energy.

'Cellulose is the most abundant reservoir of renewable hydrocarbons in the world,' explained David Ehrhardt of Carnegie Institution's Department of Plant Biology and co-author of the paper.

'To understand how cellulose might be modified and how plant development might be manipulated to improve crop plants as efficient sources of energy, we need to first understand the cellular processes that create cellulose and build cell walls,' he added.

As a starting point, the scientists used findings from a previous study (also undertaken by Professor Ehrhardt and the team), in which advanced imaging techniques were used to observe cellulose molecules within the Arabidopsis plant. In that study, the group created a fluorescent version of both the enzyme that makes cellulose fibres (cellulose synthase) and the protein behind microtubules (tubulin).

The results proved that a connection exists between cell wall synthesis and microtubules (protein fibres), and it is this connection that determines the shape of the cell. For the current study, the team turned their attention to how the association between the cellulose synthase complexes and microtubules is triggered.

They concluded that the protein network behind cellulose has a dual function; in addition to providing the framework for the structure of cell walls, it acts as a 'traffic cop', directing the important molecules that promote growth to the places they are needed. This means that we now know how the enzymes appear at the right position in the cell to create cellulose and ensure that the plant cells have the right shape.

The findings also helped the scientists to add a new layer of information to the processes at work in the movement of plant microtubules, which they refer to as 'treadmilling'.

They believe that the structures within the cell that contain cellulose synthase and that remain with the microtubules during longer, stressful periods are connected to this process, and it is only when the stress is lifted that the cellulose synthase is delivered by the organelles to the cell membrane.

For more information, please visit:
Carnegie Institution for Science: http://www.ciw.edu/
Wageningen University: http://www.wageningenuniversiteit.nl/UK/
Nature Cell Biology: http://www.nature.com/ncb
New and Emerging Science and Technology (NEST) under FP6: http://cordis.europa.eu/nest/