How does rice cope with too little oxygen during its early life?

Most crops cannot germinate underwater. Rice exhibits certain degrees of tolerance to oxygen deficiency for anaerobic germination (AG) and anaerobic seedling development (ASD). Direct rice seeding, whereby seeds are sown into soil rather than transplanting seedlings from the nursery, becomes an increasingly popular cultivation method due to labor shortages and opportunities for sustainable cultivation. Flooding is common under direct seeding, but most rice varieties have poor capability of AG/ASD, which is a major obstacle to broad adoption of direct seeding. A better understanding of the physiological basis and molecular mechanisms regulating AG/ASD should facilitate rice breeding for enhanced seedling vigor under flooding. This review highlights recent advances on molecular and physiological mechanisms and future breeding strategies of rice AG/ASD.

Automated summary

Rice exhibits some tolerance to oxygen deficiency for anaerobic germination and seedling development. Direct seeding is becoming more popular due to labor shortages, but most rice varieties have poor capability of anaerobic germination/seedling development, hindering its broad adoption. A better understanding of the physiological and molecular mechanisms regulating anaerobic germination/seedling development in rice could facilitate breeding for enhanced seedling vigor under flooding conditions.