Pigmented Rice: Flavonoid and Nutritional Dynamics under Climate Changes

Rice (Oryza sativa L.) is a staple cereal crop that sustains billions of people worldwide. Unlike other cereals, rice boasts a rich diversity of pigmented landrace varieties, including red, brick-red brown, and purple rice, which originated in the upland and lowland regions of Yunnan, China, Northern Thailand, and Myanmar. The ancestors of cultivated rice, Oryza rufipogon and O. nivara, also exhibited pigmented grains, suggesting a deep evolutionary history. Despite this, the neo-domestication of cultivated pigmented rice remains poorly understood, necessitating further investigation through advanced genomic tools such as Pangenomics and Epigenomics. Recent studies have identified flavonoids, anthocyanins, pro-anthocyanins, and carotenoids as key compounds responsible for the diverse coloration in rice plant organs. However, the interaction between these pigments and environmental stresses, such as heat and cold, and their impact on nutritional profiles, remains an area ripe for exploration. The discovery of leaf chlorophyll and flavonoid pigment mutants has further highlighted the complex relationship between leaf coloration, photosynthetic efficiency, and nutritional properties, underscoring the need for more comprehensive research.

This research topic aims to elucidate the intricate relationships between environmental stresses and flavonoid content in pigmented rice varieties. Specifically, it seeks to understand how these interactions can stabilize pigment expression and enhance the nutritional profile of both leaves and grains. By leveraging recent advancements in Pangenomics and Epigenomics, the research will address key questions about the genetic and epigenetic mechanisms underlying pigment accumulation and stability. The ultimate goal is to provide a more robust framework for the neo-domestication of pigmented rice varieties, thereby improving their nutritional value and adaptability to diverse environmental conditions.

To gather further insights into the genomic and nutritional aspects of pigmented rice, we welcome articles addressing, but not limited to, the following themes:

- The current status of Pan-genomics of genetic variation among wild ancestors, local landraces, and cultivated pigmented rice varieties found in upland, terrace, and lowland rice cultivation systems.

- Current understandings of Neo-domestication of local landraces leading to improved pigmented rice varieties cultivated globally.

- Research on hidden epigenomes, transcriptomes, metabolomes, and phenomes regulating the expression, accumulation, and stability of various pigments, including flavonoids, chlorophyll, and carotenoids, in different plant organs, with a focus on nutrient composition, particularly in leaves and grains.