A Hiroshima-University-led research team has discovered a key gene responsible for the initiation of gemma development, acting as a "master switch" to start asexual reproduction (cloning) in the model plant Marchantia polymorpha (common liverwort).
Many plants possess the extraordinary ability to bypass seeds and reproduce through asexual reproduction. This flexibility allows plants to reproduce entire bodies from a specialized cell. However, the exact cellular and genetic "switches" behind this process have remained a mystery.
While such capacity is widespread across the plant kingdom, it remains a challenge to study. The primary reason is that standard model organisms, such as Arabidopsis thaliana, do not naturally reproduce in this manner. Consequently, a "scientific blind spot" has emerged, where the most advanced tools of molecular biology could not be applied to this fascinating phenomenon.
A Hiroshima-University-led research team was fortunate to uncover this hidden mechanism by shifting their focus to an emerging model organism, Marchantia polymorpha (common liverwort). Widely found in inhabited areas of the Northern Hemisphere, this plant has a flat, leaf-like body called a thallus and can reproduce by cloning itself through specialized structures known as "gemmae".
Their research was published in the journal Current Biology on May 4, 2026.
"Marchantia polymorpha is a key to solving the mystery of asexual reproduction in plants," says Yuki Hirakawa , professor at Hiroshima University's Graduate School of Integrated Sciences for Life . "This is because this species spontaneously undergoes asexual reproduction by forming gemmae, and well-established methods for genetic analysis are already available."
In previous work, the research team found that the CLE peptide hormone suppresses asexual reproduction. Subsequent transcriptome analysis identified a set of genes that changed expression in response to the hormone, leading the team to suspect their involvement in asexual reproduction. In this study, the team conducted CRISPR-Cas9 genome editing and artificial microRNA knockdown experiments to suppress the function of one of these genes. They found that the plant completely ceased gemma production, revealing that this gene, named GEMMIFER, is essential for asexual reproduction.
To further analyze the gene's function, the team created a transgenic line capable of controlling the activity of GEMMIFER via drug administration. When dexamethasone was applied to transiently activate GEMMIFER, it triggered the formation of stem cells, the starting point of gemma development. These newly formed cells continued to grow and successfully developed into mature gemmae. This confirmed that the activation of this single gene is sufficient to set the entire cloning process in motion.
Further analysis revealed that GEMMIFER functions by activating the gene GCAM1, which previous studies have shown is also required for gemma formation. This interaction provides key insights into the early stages of the genetic pathway that triggers the stem cell identity of gemma.
"The precise way this gene reprograms cell fate is still not fully understood. Furthermore, while many plants possess similar genes, it remains to be seen whether they share the same functional role."
"However," Hirakawa adds, "the fact that we couldn't observe this in traditional model plants didn't mean it wasn't happening elsewhere in nature. This discovery reminds us of the vast biological secrets still waiting to be uncovered."
Go Takahashi & Masaki Shimamura at Hiroshima University; Tomohiro Kiyosue & Saori Yamaya at Gakushuin University; Facundo Romani, Ignacy Bonter & Jim Haseloff at the University of Cambridge; and Kimitsune Ishizaki at Kobe University co-authored this study.
