MpTCP1 controls cell proliferation and redox processes in Marchantia polymorpha

Area of Science:

• Plant Biology
• Developmental Biology
• Evolutionary Biology

Background:

• TCP transcription factors are crucial for cell proliferation in flowering plants (angiosperms).
• The conservation of TCP gene regulatory functions across diverse land plant lineages, particularly early-diverging ones like liverworts, remains largely unexplored.

Purpose of the Study:

• To investigate the function of the TCP-P clade gene, MpTCP1, in the early land plant lineage Marchia polymorpha.
• To determine if TCP transcription factors' growth regulatory roles are conserved in non-vascular plants.

Main Methods:

• Generation and analysis of MpTCP1 knockout mutants (Mptcp1ge).
• Comprehensive characterization including cell proliferation assays, morphological analysis, gene expression studies (mRNA, transcriptome), chemical analysis, and DNA binding assays.
• Investigation of MpTCP1 protein interactions with DNA and its redox sensitivity.

Main Results:

• Mptcp1ge mutants exhibited reduced vegetative growth and aberrant tissue formation in reproductive structures.
• Mutant plants showed elevated hydrogen peroxide (H2O2) levels and increased thallus pigmentation due to secondary metabolite accumulation (e.g., aminochromes).
• MpTCP1 proteins bind DNA in a redox-dependent manner and regulate a network of genes involved in H2O2 metabolism.

Conclusions:

• MpTCP1 plays a context-dependent role in regulating Marchia growth.
• The redox sensitivity of MpTCP1's DNA binding provides a mechanism for responding to oxidative stress.
• These findings suggest MpTCP1's activity contributed to the morphological diversification and adaptation of early land plants.