Western Odisha Heirloom Rice Cultivars: A Storehouse for UV-B Tolerance Traits

<jats:p>Due to the escalating impacts of climate change, a new physicochemical stressor, UV-B radiation, has emerged in the biosphere. Mankind and plants are facing the adverse impacts of harmful UV-B radiation. Although crop yields are affected by UV-B stress, the precise nature of these effects remains unclear, and predictions about how rice crops will respond to UV-B radiation stress are uncertain. Environmental stressors related to UV-B do not act in isolation but can interact in complex ways. The stressors could exhibit opposing, cumulative, or synergistic effects. The synergistic interactions can cause more damage than expected. Multiple studies have shown that UV-B exposure and reactive oxygen species production are closely linked. The increasing production of reactive oxygen species damages proteins, lipids, carbohydrates, and nucleic acids and impairs their structures and functions. The stress reduces biomass accumulation, plant height, photosynthetic efficiency, and leaf area expansion in sensitive species. UV-B resilience in plants occurs through a combination of physiological responses and signalling pathways. The acclimation process triggered by UV-B exposure involves the synthesis of specific metabolites, including proline, flavonoids, anthocyanins, unsaturated fatty acids, and several antioxidants. These metabolites are known to protect against UV-B radiation by directly screening excessive light energy and supporting repair mechanisms. Despite numerous studies, there is no consensus on how to produce a sustainable rice crop under climate change-induced conditions. Among rice genotypes, UV-B sensitivity is species-specific; some heirloom cultivars are more tolerant than high-yielding rice varieties. This trait is linked to the agricultural niche where the landraces are cultivated. It is noted that tolerance to UV-B stress in some heirloom cultivars from western Odisha is unique and has been inherited through generations of cultivation in the area. The tolerance arises from various defence mechanisms developed over time in their native environment, such as the accumulation of non-enzymatic antioxidant flavonoid compounds in plant organs. The review offers an in-depth discussion of this subject to ascertain the potential role of these rice cultivars in ensuring food security for consumers under climate change.</jats:p>