Nitric Oxide: A Double-Edged Sword in Photosynthetic Stress Responses

Nitric oxide (NO), a small gaseous molecule with redox activityserves as a central regulator of growth, development, immunity. This remarkable signaling molecule orchestrates a complex symphony of biological responses, navigating through intricate pathways that influence essential aspects of plant life. The absence of canonical Nitric Oxide Synthases (NOS) in higher plants has led to the discovery of alternative NO production pathways, featuring key contributors like nitrate reductase (NR) in mitochondria, peroxisomes, and chloroplasts. In the realm of plant physiology, NO emerges as a multifaceted player, significantly impacting reproduction, symbiotic interactions, senescence, and defense mechanisms. In symbiotic relationships, NO plays a pivotal role in interactions with rhizobia, mycorrhizae, and lichens, influencing nodule development and senescence. Furthermore, NO governs plant senescence, acting both as a signaling molecule and a modulator of hormone-induced processes. In defense responses, NO collaborates with reactive oxygen species, influencing hypersensitive cell death. Beyond growth, NO showcases its potential in postharvest applications, preserving sensory attributes, enhancing nutritional quality, and serving as an eco-friendly alternative for pest and disease control in horticultural crops. As research delves deeper, unveiling additional dimensions of NO's contributions, it holds promise for innovative applications in agriculture, environmental management, and sustainable horticulture.