Single-nucleus sequencing deciphers developmental trajectories in rice pistils

Area of Science:

• Plant reproductive biology
• Cellular and molecular biology
• Genomics

Background:

• Angiosperm life cycles involve alternating sporophyte and gametophyte generations.
• Rice pistils are vital for fertilization and grain production.
• The cellular landscape of rice pistils remains largely uncharacterized.

Purpose of the Study:

• To perform a comprehensive cell census of rice pistils prior to fertilization.
• To identify cell types and understand cellular heterogeneity within the rice pistil.
• To elucidate the developmental trajectories of germ and carpel cells.

Main Methods:

• Droplet-based single-nucleus RNA sequencing (snRNA-seq) was employed for a high-throughput cell census.
• Ab initio marker identification and in situ hybridization were used for cell-type annotation.
• Comparative analysis of 1N (gametophyte) and 2N (sporophyte) nuclei and trajectory analysis were performed.

Main Results:

• snRNA-seq revealed significant cell heterogeneity between ovule- and carpel-derived cells.
• The developmental path of germ cells in ovules showed pluripotency resetting before the sporophyte-gametophyte transition.
• Trajectory analysis highlighted novel aspects of epidermis specification and style function in carpel cells.

Conclusions:

• This study provides a systems-level understanding of rice pistil cellular differentiation and development.
• The findings lay a foundation for future research into plant female reproductive development.
• The characterized cell census offers insights into the genetic regulation of pistil development.