US and Chinese researchers have identified the genetic mechanisms underlying leaf shape diversity in plants. The data obtained will allow plants to adapt to different climate zones and increase their productivity by controlling leaf formation at the genetic level.

The shape, size, structure and complexity of the structure of plant leaves, in addition to the general diversity in nature, can vary significantly even in different varieties of the same species. The observed differences did not arise by chance. These arise from the need for thermoregulation, the management of the water regime of the leaves, and the adaptation of plants to environmental conditions such as air humidity and amount of sunlight.

The variety of leaves is determined mainly by two factors: the complexity of the leaf and the characteristics of its edge. A simple sheet consists of one flat plate, and a complex sheet consists of several simple plates. In turn, the edge of the sheet can be solid, serrated, or lobed with different serration depths.

To determine what the nature of leaf development depends on, biologists from the University of Maryland (USA) and the Shenzhen Institute of Synthetic Biology (China) studied their formation using the example of wild strawberries (Fragaria vesca). The researchers identified two key regulatory pathways involved in the development of different leaf structures in three strawberry mutants. Scientists explained the results of their study in an article published in the journal. Current Biology .

Usually strawberries form complex leaves consisting of three separate leaves, each with clearly defined teeth on the edge. However, a mutant with a single leaf instead of a triple leaf was recently discovered. In a new study, an international team of biologists identified a mutant with three leaves but deeper teeth.

After examining the genomes of these three strawberry varieties in detail, the scientists discovered two independent pathways in which the genetic factors SL1 and SALAD determine the complexity and serration of leaves, respectively. The more the SL1 factor is synthesized in the leaf bud, the more complex it will be: triplet, quintuple, etc. On the contrary, the less SALAD factor is formed in the cells at the leaf edge, the deeper the teeth appear. Surprisingly, these two ways of regulating leaf shape eventually converge and affect the functioning of the same CUC2 gene, which is largely responsible for the growth and division of plant cells.

Moreover, biologists’ conclusions are not limited to strawberries and can be applied to many other plants as well. Experiment with: Arabidopsis thaliana – a standard model plant – showed a similar arrangement of leaf characteristics. According to the researchers, this relationship can be used to help plants adapt to or tolerate a wider range of conditions in different climate zones.

“If we can adjust this regulation, for example, we can make the plant produce more biomass, which could potentially lead to increased fruit production. We can also expand the adaptability of this strawberry by moving it outside of its natural environment and changing its leaf morphology. For example, having more teeth increases resistance to cold.” The authors of the new study stated that wider and smoother leaves would be better adapted to a warmer climate.