Olomouc Scientist Helped Discover a New Plant Enzyme
An international team of scientists discovered an enzyme that determines which plant wins the battle for light in dense ground vegetation. An Olomouc scientist, Ondřej Novák from the Laboratory of Growth Regulators, which is a joint project of the Faculty of Science at Palacký University and the Institute of Experimental Botany of the Academy of Sciences of the Czech Republic, participated in this international research. The discovery was recently published in the prestigious journal Nature Chemical Biology and can be applied, for instance, in the cultivation of crops of agricultural importance.
Novák claims that plants can be compared to living factories, which are able to transform light energy into chemical energy. This is possible due to a complex of biochemical reactions, when water and carbon dioxide change into sugar (glucose) in the presence of sunlight and chlorophyll. The maximum efficiency of the process is guaranteed by the growth of the aboveground parts of plants upwards, toward light. The mechanisms controlling their growth, however, have not yet been precisely recognized. A major shift was made after three years of research, in which Novák participated along with colleagues from the United States and Sweden.
Enzyme coordinating the amounts of phytohormones
The elongation of stems is significantly influenced by a plant hormone called auxin. Another hormone, ethylene, is involved in the elongation of leaf stalks. ‘The research proved that the production of auxin and ethylene, influencing the elongative growth in plants, was interlinked with one particular enzyme. A series of experiments resulted in the identification of a new VAS1 gene responsible for the production of an enzyme, which reduces the production of auxin and ethylene from amino acids. This proved to be one of the key factors determining which plant in the dense bushes manages to reach a spot with sufficient light,’ says Novák. The scientists used Arabidopsis thaliana, or thale cress, as their model plant. Thale cress thus allowed them to explain the background of a vital phenomenon in the plant world—photosynthesis.
Novák explains that VAS1 also functions in relation with another previously described gene called TAA1, which is also responsible for the production of auxin, hence the elongation of the stem as well. ‘In normal conditions, the enzymes coded by the genes TAA1 and VAS1 work against each other. By eliminating one of them, the balance is disturbed. It results in a plant unable to elongate while shaded, or a plant overly elongated even in full light. Only the functionality of both genes allows Abaridopsis to employ the full range of possibilities, that is, the production of compact mass in autonomous growth as well as the maximum elongation convenient for growth in dense bushes,’ says Novák.
Significant in cultivation of staple crops
Despite the fact that Abaridopsis is only a model plant, plant biologists still consider it a major discovery, since it allows better understanding of how plants work. These findings can be used for example for improvement of economic parameters in cultivation of major staple crops. By means of phytohormones, the ratio between the useful parts of the plants and the ‘waste’ can be regulated. (For example, between fruits and stems.) Phytohormones can also be used to affect the way the stems lay on the ground, which has an effect on the difficulty of harvesting.
The future of the project is still open, the U.S. scientists are attempting to better specify the characteristics of the individual VAS1 genes, consisting of eight various types, and to precisely determine their functions. A publication in one of the Nature Publishing Group journals is a prestigious achievement, since it must be supported by important scientific findings.
Abaridopsis is an important model plant species, often used in molecular biology for its simplicity and low demands in cultivation. Abaridopsis also fulfils other conditions imposed on model plants—a small genome, short recovery time between two generations, and sufficient offspring. It is one of the most widespread model plants in biology laboratories.