Montana State Plant Science Research Explores Protein Distribution In Barley

Bozeman – Protein content in wheat and barley crops can influence everything from the plant’s effectiveness as livestock feed to the clarity of beer brewed with the crops. Research in Montana State University’s College of Agriculture is seeking to identify exactly which plant enzymes control this critical crop value.

Andreas Fischer, Department of Plant Sciences and Plant Pathology professor, is using recent funding from the U.S. Department of Agriculture’s National Institute of Food and Agriculture to fill what he calls a foundational gap in plant science knowledge. The work could ultimately find applications in the development of new grain varieties, an area in which MSU is a regional leader.

Fischer’s work focuses on plant senescence, the process by which maturing plants break down at the end of their annual life cycle.

“We see it every fall when the leaves go from green to yellow,” said Fischer. “What we see there is really the loss of green leaf pigment, chlorophyll, which is being degraded.”

As leaves age, plants break down chloroplasts, where chlorophyll and most leaf proteins are located. Through that process, they release a large amount of nitrogen. That nitrogen can then be transported and repurposed into the growing grains of the wheat or barley plant. Fischer’s exploration will examine the first step in the process to identify which enzymes in the plant are responsible for releasing nitrogen from chloroplast proteins.

“We’ve known for most of the last century that proteases are the enzymes that degrade proteins,” said Fischer. “But plant genomes encode something like 700 or 800 proteases, and we only know what a small fraction of those are actually doing in the plant.”

Fischer’s project, which will be supported by a USDA NIFA grant of just under $650,000, continues previous work that narrowed down the number of potential proteases to about six. It is one of 22 projects around the nation funded by a $12 million initiative focused on plant production.

Using a method called transcriptomics, Fischer and collaborators at the Weizmann Institute of Science in Israel have identified proteases that are activated when barley leaves begin degrading chloroplasts and accessing stored protein. With the new funding, they will genetically turn some of those enzymes off to see if that interrupts the timing and extent of protein redistribution.

“If we know which proteases are important, we can search through barley germplasm and maybe find naturally occurring instances in which that enzyme is not present or is more or less active, which can help adjust seed protein content,” said Fischer. “At some level, it’s very basic science, basic plant biology, that we just don’t understand very well.”

“Being able to breed wheat and barley varieties with higher or lower protein content would help MSU continue its long history of meeting producer needs through plant breeding”, said Fischer. Barley with higher protein, for instance, is often better for livestock feed, while barley with lower protein content is better for malting and brewing.

MSU’s grain varieties have historically proven popular with Montana growers. According to the USDA’s National Agricultural Statistics Service, MSU’s Vida spring wheat was the state’s leading variety last year with more than 600,000 acres planted, while Warhorse, another MSU variety, was the leading winter wheat variety at more than 350,000 acres.

Hockett, released in 2008, was the second most popular barley variety in Montana, while Haybet and Haxby led the forage and feed categories, respectively. All three are MSU-developed barley varieties. Refining existing lines and developing new ones means that the university can continue serving grain producers by providing them with the varieties that best suit their geographic area and production purposes, and Fischer said the current project will help to further advance variety development.

“The analytics might take a year or two, and then we can start testing experimental barley lines to see if we have the expected results,” he said. “Figuring out these proteases might be another screw we can turn to tune the system a bit more.”


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