Guo et al. demonstrate that alternative splicing of REGULATOR OF LEAF INCLINATION 1 modulates phosphate signaling and plant growth in the face of phosphate deficiency.
By Meina Guo, Wenyuan Ruan, and Keke Yi
Background: Phosphate (Pi) limitation represents a primary constraint on crop production. To better cope with Pi deficiency stress, plants have evolved multiple adaptive mechanisms for phosphorus acquisition and utilization, including the alteration of growth and the activation of Pi starvation signaling.
Question: Despite significant advances in understanding the mechanisms underlying the regulation of Pi-associated shoot architecture, Pi-signaling, and Pi-homeostasis under Pi deficiency stress in plants, how these strategies are coordinated remains largely unknown.
Findings: We provide evidence that the alternative splicing (AS) of REGULATOR OF LEAF INCLINATION 1 (RLI1) produces two protein isoforms in rice: RLI1a (containing MYB DNA binding domain) and RLI1b (containing both MYB and coiled-coil [CC] domains). Both RLI1a and RLI1b can modulate Pi starvation signaling. However, the absence of the CC domain in RLI1a enables it to directly activate a broader range of target genes than RLI1b, including genes involved in both brassinolide biosynthesis and signaling, thereby modulating plant growth. We also found that the AS of RLI1-related genes for both Pi signaling and growth is a widely present mechanism in plants.
Next steps: Given the functionally conserved strategy to orchestrate Pi starvation signaling and growth in plants, we aim to create smart crops with ideal shoot architecture and high phosphorus utilization efficiency by molecular design breeding.
Meina Guo, Yuxin Zhang, Xianqing Jia, Xueqing Wang, Yibo Zhang, Jifeng Liu, Qingshen Yang, Wenyuan Ruan, Keke Yi. (2022). Alternative splicing of REGULATOR OF LEAF INCLINATION 1 modulates phosphate starvation signaling and plant growth. https://doi.org/10.1093/plcell/koac161