Amaranth: From Aztec tradition to climate-smart agriculture – Examining genetic resources, nutritional benefits, and resilience

Pressing challenges of rising food demand, malnutrition, competition for essential resources (land, water and energy), changing climate, and unforeseen events such as pandemics, have heightened the urgency for resilient, nutritious and diversified crops. Amaranth, an ancient grain with roots in Aztec culture, comprising of approximately 60–70 species can be categorized as vegetable, grain, or wild types. Known for its remarkable nutritional profile – rich in protein, squalene, essential amino acids and unique phytochemicals – amaranth has re-emerged as a superfood. Its resilience to environmental stress, low care and availability of diverse genetic resources for breeding, makes it a promising candidate for addressing modern agricultural challenges. In this review, we explore into the diverse aspects of amaranth that positions it as a key player in tackling food security and agricultural issues. It explores the historical context and geographical distribution of grain amaranth, tracing its journey from a staple food in ancient diets to its reintroduction as a superfood. The major points include: 1) C4 efficiency and stress tolerance detailing mechanism along with anatomical and biochemical adaptations; 2) advances in genomics, including high-quality genome assemblies and plastome characterization crucial for understanding its evolutionary relationships and genetic diversity; 3) specific databases that facilitate access to genomic information and support population genetic analyses for crop improvement; and 4) potential as a functional food and its therapeutic benefits. Collectively, this review advocates for amaranth as a super crop with significant promise for enhancing global food security and promoting sustainable agricultural practices, while suggesting future avenues for research.