Assembly of Arundinella anomala genome to facilitate single-cell resolved functional and developmental...

C₄ plants operate a highly efficient photosynthetic CO₂ concentrating mechanism. However, C₄ photosynthesis represented by maize is based on the typical Kranz-type leaf anatomy, which involves complex regulation of vascular development coupling with metabolic distribution. To explore the possibility of using alternative C₄ leaf anatomy as reference for engineering C₃ crops, we sequenced, assembled and annotated the genome of Arundinella anomala, a C₄ grass with variant Kranz anatomy and interveinal distinctive cells (DC). Following single-cell level transcriptomes for comparative analyses between C₄ bundle sheath and DC cells, genetic and metabolic support for the intensified C₄ function of DC cells were observed, including increased cyclic photosynthetic electron transport, carbon fixation and starch synthesis. Further, the mechanism involving SHORT-ROOT (SHR) and auxin to trigger independent development or proliferation of DC cells was explored. Notably, spaced distribution of DC-like cells can be achieved in rice leaves by inducing the expression of ZmSHR1. This work laid a foundation for introducing functional DC-like cells among the intervascular mesophyll cells of C₃ grass leaves, and provided resources and strategies for engineering C₄ traits into C₃ crops.