Mini foxtail millet as a new C4 model species (Nat. Plants) ($)
The three most widely adopted plant models all use C3 photosynthesis, but discoveries made in these plants are not always applicable to C4 plants. Foxtail millet (Setaria italica) has been emerging as a potential C4 model species, but its use for genomics research is challenging due to long generation time and recalcitrance to genetic transformation. Through a large-scale mutagenesis screen, Yang et al. have characterized a mini rapid-cycling mutant of foxtail millet -named xiaomi – as a promising new model system for C4 plants. xiaomi mutants harbour a point mutation in the Phytochrome C (PHYC) gene leading to a premature stop codon and impairing the essential function of this light receptor in photoperiodic flowering. The small stature and fast life cycle of xiaomi enables completion of 5-6 generations within one year and with similar space requirements to the equivalent amount of Arabidopsis. The authors assembled and annotated a high-quality reference genome for xiaomi and an online dynamic gene expression atlas. Finally, they established an efficient Agrobacterium-mediated genetic transformation system using embryonic calli. Future research with xiaomi could help investigate many characteristics of C4 plants for improvement of agricultural species. (Summary by Katy Dunning @plantmomkaty) Nature Plants 10.1038/s41477-020-0747-7
