A new enzyme responsible for making two cotyledons

September 13, 2018

Will further understanding of the relationship between plant shape and metabolic reaction

Joint research by RIKEN CSRS, the National Institutes of Natural Sciences and the University of Tokyo has discovered that the CYP77A4 enzyme, which is related to fatty acid metabolism, works to ensure the development of two cotyledons in plant seeds. Most seedlings begin with two cotyledons neatly separated into left and right, with the number and location of emergence already having been decided.

This collaborative research focused on the relationship between metabolic reaction and plant size and shape. The researchers prepared 35 Arabidopsis thaliana strains with mutations in their cytochrome P450 genes (which encode for oxidases) and measured 12 indicators related to shape and size, such as root length and leaf size. They found that in the cyp77a4 mutant strain, which cannot properly produce CYP77A4, the number and shape of its cotyledons was abnormal and did not emerge from the seed separately on the left and right. Examining the auxin distribution in the mutant embryos revealed that CYP77A4 assists cotyledon development by properly distributing auxin in the embryo.

These results propose an effective means for finding metabolic reactions related to plant formation. Applying this method to other enzymes and organisms is expected to lead to a deep understanding of the relationship between metabolic reactions and plant shape and size.

Original article
Development doi:10.1242/dev.168369
K. Kawade, Y. Li, H. Koga, Y. Sawada, A. Kuwahara, H. Tsukaya, M. Yokota Hirai,
"The cytochrome P450 CYP77A4 is involved in auxin-mediated patterning of theArabidopsis thaliana embryo".
Masami Hirai; Team Leader
Kensuke Kawade; Visiting Scientist
Metabolic Systems Research Team