Seminars

Plant responses to environmental stress form a complex molecular network that has been crucial for terrestrial adaptation. However, the functional expansion and evolvability of such network during plant terrestrialization remain poorly understood. In our recent study, we compared the transcriptomic responses to key nutrients (nitrate, phosphate, and sucrose) in the bryophyte Marchantia polymorpha and the streptophyte alga Klebsormidium nitens. We found that the largely species-specific nutrient response patterns are driven by alterations in gene regulatory networks (GRNs). Interestingly, while the core pathways governing these GRNs show modest conservation, M. polymorpha exhibits more extensive regulatory connections through the redeployment of transcription factors like CSD. We further revealed that pre-existing cytokinin signaling machinery in M. polymorphais co-opted into nutrient-responsive pathways. These findings highlight genetic co-option events that could be contributed to the successful establishment of land plants. Additionally, I will introduce our recent efforts to identify M. polymorpha genetic mutants with altered responses to nutrient stress using hyperspectral imaging. By decomposing thallus hyperspectral reflectance, we identified the transcription factor MpWRKY10, whose knockout leads to abnormal pigmentation under phosphate deficiency, possibly via R2R3-MYB transcription factors and phenylpropanoid pathway genes.