‘Unimportant’ plant gene turns out to be essential
Leiden biologists have shown that a gene present in plants, animals and yeasts does play an important role in plants, although for years the gene was considered unimportant. It turns out the gene plays a crucial role in the development of vascular tissue in plants. Publication in Nature Plants on 11 May.
Plant scientists have wondered for years, according to Remko Offringa, professor of Plant Developmental Genetics at the Institute of Biology Leiden (IBL): why isn't the PDK1 gene important in plants? The same gene also occurs in yeasts and animals, and these organisms are not viable if the gene is inactivated. In plants, on the other hand, the PDK1 gene was considered unimportant, because thale cress (Arabidopsis thaliana) plants with a mutated PDK1 gene look similar to plants with an active PDK1 gene. Former PhD student Yao Xiao and professor Offringa proved the importance of the PDK1 gene and discovered its function in plants.
It appears that scientists have made the wrong assumption about the available pdk1 thale cress mutants for years. During his PhD research into the plant hormone auxin, Xiao discovered that, in contrast to what was claimed in previous studies, the PDK1 gene in these mutants is still active. Using the CRISPR-Cas9 gene technique, Xiao completely disrupted the PDK1 gene. It resulted in small plants that are defective in their reproduction and produce only a few seeds. ‘These mutants will never survive in nature,’ according to Offringa, ‘so the PDK1 gene is essential for plant development.’
The plant hormone auxin plays a central role in the development of the plant. Its polar transport from cell to cell directs amongst others the formation of vascular tissue, which transports nutrients throughout the plant. Xiao found out that the PDK1 gene regulates auxin transport, and thereby steers the development of vascular tissue.
Back to back publication
The Leiden study is published in Nature Plants alongside a paper on the same gene by a team of scientists from China and Austria. Offringa: ‘We put our paper online at bioRxiv so that the scientific community could respond. A researcher from Austria, with whom I co-authored several publications, saw the article and informed me that they were working on the same gene.’ Instead of competing with each other, the researchers decided to work together. Offringa: ‘There is overlap in the studies, but we also have our unique results, and our conclusions also have similarities and differences. The two studies are now published back to back in the same issue so that people can draw their conclusions, just as science should work.’
At the end of April, another study by professor Offringa was also published in Nature Plants. In this article, he and his colleagues described a longevity gene in plants: the gene can bring annual plants back into a growth phase after flowering, instead of the plants dying. The news received quite some media attention.