Wang Ying's research group in the School of Life Sciences collaborated to discover conserved molecular modules that regulate plant organogenesis

   In the process of evolution, innovative organs and structures in multicellular organisms have emerged one after another, playing a key role
in the adaptation of organisms to the environment.
Plant landings are major events in the evolutionary history of plants; As plants migrate from aquatic to terrestrial environments, different plant lineages evolve unique morphological and anatomical structures that also give plants the ability to
explore new environments.
However, their cytological origin, molecular regulatory mechanisms, and future evolutionary trends remain unclear
.
Given the high similarity of gene composition between different taxa, it can be speculated that the new structure is likely to originate from existing structures, and its emergence and development are likely to be based on the reuse
of existing regulatory pathways and regulators.

On November 18, Wang Ying's research group from the School of Life Sciences, University of Chinese Academy of Sciences, and Jiao Yuling's research group from the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, published a report at Science Advances The research paper "A conserved module in the formation of moss midribs and seed plant axillary meristems" reveals the conserved molecular developmental modules
behind the two structures of the leaf midrib of Bulbophyllum microceptifolia and Arabidopsis axillary buds.
As a support and transport structure, the midrib of the leaf of Bulbophyllum spp.
and the surface capillary transport jointly mediate the water conduction and improve the water transport efficiency
of bryophytes.
The leaf axillary meristem (axillary buds) of seed plants can form lateral branches, forming new growth axes; The number of lateral branch structures determines the overall structure of the plant and affects fruit or seed yield
.
This study found that although the anatomical structures of the two are completely different, they share a common molecular mechanism
that regulates the occurrence and development.
In this work, the researchers combined molecular genetics, laser confocal microscopy, transcriptome sequencing analysis and external hormone and chemical drugs to carefully track and compare the cytology process of non-homologous organ formation, and found that in seed plants and bryophytes, the common themes of axillary bud occurrence and leaf midvein formation are cell division, while GRAS family transcription factors LATERAL SUPPRESSOR (LAS) PROMOTES THE FORMATION
OF THESE TWO NON-HOMOLOGOUS STRUCTURES BY REGULATING CELL DIVISION.
By revealing the regulatory role of LAS in the cytology process of cell division, this work provides a new perspective and strong evidence for elucidating the molecular mechanism of organ origin and evolution, and also proposes a universal mechanism, that is, the overall inheritance and reactivation of conserved molecular regulatory modules in the process of evolution, which is the basis for
innovative organ and structure formation.

Postdoctoral researcher Ge Yanhua and doctoral student Gao Yi are the co-first authors of the paper, and Associate Professor Wang Ying and Professor Jiao Yuling are the co-corresponding authors
of the paper.
The research has been funded
by the National Natural Science Foundation of China, the Key Research and Development Program of the Ministry of Science and Technology, and the Basic Research Fund of Central Universities.

Figure 1 LAS (top) and Arabidopsis thaliana (bottom) regulate leaf midrib (upper) and lateral bud (bottom) formation by influencing cell division, respectively

Figure 2: LAS gene mutations affect midrib formation and leaf extension in P.
nividensis

 Figure 3.
LAS gene affects cell division activity in leaves of P.
spp