Regulation and Expression of Phytohormones for Root Architectural Trait Development in Rice: A Review

The root system architecture (RSA) in monocotyledonous plants like rice is consists of primary roots, lateral roots, seminal/crown roots, and root hairs. The soil nutrients also influence many physiological processes via various root parameters like root length, root diameter and root angle for growth and development. The variation in root system architecture in rice is influenced by the intrinsic factors (phytohormones, transcription factors) and extrinsic factors (light, temperature and moisture) and their collective effect. The phytohormones such as; auxin, cytokinin, abscisic acid and ethylene, and their mutual effects play vital role for root architectural trait development. Many genes/QTLs were identified in rice which are strong role player for root development. But the biochemical signaling pathways are not completely understood. The modern molecular tools like genome editing, sequencing and multi-omics (transcriptomics and proteomics) approaches and multi-disciplinary system biology studies can provide a better solution for this issue. To improve the sustainable food grain production under extreme environment, it is important to understand the physiological and biochemical mechanism of root development. Moreover, it is imperative to establish a resilient root system in rice cultivation in order to mitigate the overuse of chemical fertilizers, enhance nutrient efficiency, and improve climate resilience of the plant.