NEW YORK (GenomeWeb News) – In a paper scheduled to appear online this week in the Proceedings of the National Academy of Sciences, Belgian researchers reported that they have identified epigenetic profiles related to both energy use efficiency and yield in canola plants.
A team of researchers from Bayer CropScience's BioScience division, the Flanders Institute for Biotechnology, Ghent University, and the University of Antwerp demonstrated that selecting for canola, Brassica napus, with low cellular respiration altered the efficiency with which the plants use energy as well as their seed yield and epigenetic patterns.
"Although a major subject in plant research for many decennia, the understanding of the biological network controlling yield is only poorly understood," senior author Marc De Block, a senior scientist at Bayer BioScience, and his co-authors wrote. "Here we show that in canola (B. napus), energy use efficiency is a major yield component with an epigenetic feature that can be directed by recursive selection."
The researchers started with an isogenic double haploid canola line and artificially selected the plants with the highest and lowest cellular respiration rates, using these to produce four low- and three high-respiration lines.
After testing the lines and tossing out those with potentially confounding features, the researchers evaluated differences in energy use efficiency between high and low cellular respiration lines. In general, they found that canola lines with high cellular respiration rates had lower energy use efficiency and vice versa.
In field trials of these lines, the team noted, plants with low cellular respiration rates and high energy use efficiency also had eight to 20 percent higher yields.
Because these lines all stemmed from plants with the same genetic sequence, the researchers suspected different epigenetic profiles were contributing to the changes in respiration and energy use that they were detecting.
To test this, they used methylation-sensitive amplified fragment-length polymorphism analyses, cytosine extension assays, and other approaches and to look at epigenetic patterns in the canola lines. Their results suggest most of the low respiration/high energy efficiency/high yield lines had decreased histone methylation and acetylation in their third leaves. On the other hand, the high respiration lines showed the opposite pattern.
Even so, some of these epigenetic patterns appear to shift during plant development. For instance, the team reported that while high energy efficiency hybrid plants generated by crossing two energy efficient parental lines had lower than usual methylation in fourth leaf samples, they actually had higher than usual methylation in their cotyledons.
Overall, the results not only suggest epigenetic patterns can be inherited in these plants, the researchers explained, they also highlight the potential for improving plant yield through epigenetics.
"Our results show that [energy use efficiency] is a distinct feature of plant vigor and yield and that it possess an epigenetic component that can be directed by artificial selection," the team wrote. "The implementation of 'epigenetic' selection for [energy use efficiency] has the potential to increase yield in many crops and this will further contribute to a better knowledge of the epigenetic mechanism, especially in crops, for which the genomic tools are well developed."