Recently, a research team led by Professor WU Lifang from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences has successfully elucidated the stage-specific roles of plant hormones, particularly exogenous trans-zeatin (tZ), in regulating axillary bud development in Eucommia ulmoides, a high-value economic crop.
The findings were recently published in Industrial Crops and Products.
Eucommia ulmoides is a valuable tree species native to China, known for its medicinal, edible, and rubber-producing uses. While recent research has focused mainly on its medicinal ingredients and rubber properties, studies on how it grows and develops at the molecular level are still limited. In particular, how external plant growth regulators affect its regeneration and development in vitro remains an urgent question.
Building on their previously established efficient regeneration system for E. ulmoides, the researchers investigated the role of exogenous tZ, a type of cytokinin, in regulating axillary bud development. They collected axillary bud samples at five different developmental stages and conducted integrated targeted metabolomics and transcriptomic analyses.
The study revealed that E. ulmoides axillary bud development occurs in two major phases: the initial induction phase (W0–W1) and the subsequent elongation phase (W1–W4). Dynamic changes in hormone levels and gene expression patterns were observed under tZ treatment, offering insights into the stage-specific regulatory mechanisms.
Using weighted gene co-expression network analysis (WGCNA), the team identified key hormone-related gene modules and constructed a regulatory network illustrating hormone crosstalk during axillary bud growth.
“The network showing how plant hormones talk to each other during bud growth,” explained Dr. WANG Dacheng, a member of the team.
This research lays a theoretical foundation for deciphering the molecular mechanisms by which cytokinins regulate in vitro regeneration and growth in E. ulmoides, according to the team.
This study was funded by the Youth Innovation Promotion Association CAS and the National Natural Science Foundation of China.
Common regulatory network in hormone signaling pathways and zeatin biosynthesis pathway on axillary bud development of E. ulmoides. (Image by WANG Dacheng)