The Fabaceae (legume family) not only boasts a rich diversity of species but also displays a wide range of complexities in plant morphology. Economically significant, it serves as one of the primary sources of starch, protein, oil, and vegetables in human diets.

Among the legume family, soybean (Glycine max) stands as the most significant grain and oilseed crop. Despite its importance, advancements in understanding the morphogenesis of its trifoliate leaves have been limited. To date, only a handful of leaf development genes have been identified in soybeans.

In a study published in Physiologia Plantarum, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences (CAS) uncovered the overlapping roles of two LEAFY (LFY) gene copies, GmLFYa and GmLFYb, in regulating the meristematic activity of compound leaf primordia during soybean compound leaf development. This discovery contributes to our understanding of how the trifoliate pattern in soybeans is established.

The researchers analyzed the development process and identified the key early morphological markers of soybean trifoliate compound leaves. They have detailed the process of soybean compound leaf development, which began with simple primordia in the peripheral zone of the shoot apical meristem (SAM) and subsequently underwent primary and secondary morphogenesis to get its final form.

Two homologous copies of the LFY gene, GmLFYa and GmLFYb, were identified within the soybean genome, both exhibiting strong expression signals in early leaf primordia. Through phenotypic analysis of loss-of-function mutants pertaining to these genes, the researchers discovered that GmLFYa and GmLFYb perform functionally redundant roles in maintaining the meristematic activity of soybean compound leaf primordia. Additionally, they collaboratively regulate the developmental process of soybean flowers.

The study revealed the key role of LFY genes in regulating the meristematic activity of compound leaves during the development process of legume compound leaves. It also highlighted the conservation of LFY homologous genes in flower development process.

“Our study provides new genetic evidence and genetic resources for the function of LFY genes in legume morphogenesis,”said CHEN Jianghua of XTBG.

The study was supported by National Natural Science Foundation of China grants and Strategic Priority Research Programs of the CAS.

First published: 27 January 2025