Experts Pinpoint Transcription Factors Vital in Rice Caryopsis Filling

Exposure to heat usually causes obstructed grain filling during caryopsis development. This leads to a loss of yield. Because this mechanism is not yet fully understood, Huazhong Agricultural University scientists explored on the functions of transcription factors that might be involved in the process. Their findings are published in bioRxiv.

Two rice caryopsis-specific transcription factors, ONAC127 and ONAC129, have been found to respond to heat stress and are involved in the caryopsis filling process. To know more about their functions, the researchers obtained CRISPR-Cas9 induced mutants and overexpression lines of them. This led them to the discovery that both knock-out and overexpression plants exhibited incomplete filling and shrunken caryopses, which was more severe when exposed to heat stress. Further analyses also showed that ONAC127 and ONAC129 are mainly involved in stimulus response, cell wall construction, and nutrient transport.

The findings may indicate that ONAC127 and ONAC129 regulate caryopsis filling through sugar transportation and abiotic stress responses. Overall, the study demonstrates the transcriptional regulatory networks involving ONAC127 and ONAC129, which synchronizes several pathways to control caryopsis development and heat stress response during the rice filling stage.

Read more results in bioRxiv.