Plant roots play a significant role in plant growth by exploiting soil resources via the uptake of water and nutrients 72. Roots are essential for plant adaptation and productivity, but are less studied due to the difficulty of observing them during the plant life cycle 34. Roots are essential for plant productivity and serve a variety of functions, such as water and nutrient uptake, forming symbioses with other microorganisms in the rhizosphere, anchoring the plant to the soil, and acting as storage organs. The different interactions of a root with its environment depend on its organization and structure, from the cellular to whole-plant level. The root contains a stele, comprised of the xylem, the phloem, and the pericycle 67. Much of the research on root traits has thus far focused on the most common cereal crops and model plants. As cereal yields have reached their yield potential in some regions, understanding their root system may help overcome these plateaus 34.There is great potential to use the wide genotypic and agronomically induced diversity of root systems and their exuded chemicals to influence rhizosphere biology to benefit crop production 57.

Root system architecture (RSA), made up of structural features like root length, spread, number, and length of lateral roots, among others, exhibits great plasticity in response to environmental changes, and could be critical to developing crops with more efficient roots 34. Root system architecture (RSA) is an important developmental and agronomic trait, which plays vital roles in plant adaptation and productivity under water-limited environments. A deep and proliferative root system helps extract sufficient water and nutrients under these stress conditions 74.Since roots grow underground, they are the first to sense abiotic stresses and adjust their genetic program for post-embryonic development to survive the stress 43. Plant roots obtain water and nutrients from the soil, which is a complex system with intrinsic properties, abiotic and biotic interactions.

The main functions of root systems are also explored including how roots cope with nutrient acquisition from the heterogeneous soil environment and their ability to form mutualistic associations with key soil microorganisms (such as nitrogen fixing bacteria and mycorrhizal fungi) to aid them in their quest for nutrients 28.Plants growing in soil develop close associations with soil microorganisms, which inhabit the areas around, on, and inside their roots. These microbial communities and their associated genes collectively termed the root microbiomeare diverse and have been shown to play an important role in conferring abiotic stress tolerance to their plant hosts 27.

Root morphology can be affected by nutrient availability 24, osmotic stress 19, salinity 22 and light 33. A plant’s final phenotype is highly dependent on external signals, and the level of plasticity can facilitate responses to stresses 50.Phenotyping root is one of the drought management tools as roots are more prone to drought conditions and play a significant role in the plant’s life by extracting soil resources from deeper soil layers to carry on several metabolic functions in the plant’s body and its phenotyping helps to understand different root traits 72.Root traits such as fine root diameter, specific root length, specific root area, root angle, and root length density are considered useful traits for improving plant productivity under drought conditions72.Root development is controlled by auxin and cytokinin signaling 49 and is modulated by external stimuli through other hormones and alterations in auxin or cytokinin sensitivity 30.So that, understanding interactions between roots and their surrounding soil environment is important, which can be improved through root phenotyping 72.Finally, the main objective of this seminar paper is to review the response of root system architecture and root phenotypic for biotic and abiotic stress.