Botany, associated microbiota, traditional medicinal uses, and phytochemistry of Vachellia tortilis subsp. raddiana (Savi): A systematic review

Vachellia tortilis subsp. raddiana is a well-adapted tree to the severe climatic conditions prevailing in arid and desert regions. Its adaptation is mainly related to a deep root system and small leaves, in addition to its interaction with different beneficial microorganisms, such as mycorrhizas, nitrogen-fixing rhizobia, phytobeneficial rhizobacteria, and endophytes. Given its adaptation, vachellia is considered a suitable pioneer plant to be used in rehabilitation, restoration, and reforestation programs in areas threatened by desertification. Moreover, it's a valuable source of diversified bioactive chemicals such as phenolic acids, flavones/flavonols, flavonoids, and isoflavones. Beyond the direct usage of raw plant extracts as potential drugs, the different parts of the tree (seeds, leaves, gum exudates, etc) are used traditionally to treat diseases such as allergy, inflammatory reactions, cough, gastric irritation, and diarrhea. They also have antibacterial, antifungal, anti-malarial, antiviral, anti-parasitic and anti-diabetic properties. This review highlights the need to update the current scientific knowledge concerning this tree and several research paths are proposed, such as (i) using genomic approaches for studying the diversity and putative functions of the tree associated-microbiota, (ii) systematic evaluation of potential microbial positive impacts on tree growth and adaptation in the current climate change context, (iii) investigating the effect of the microbial endophytes on the tree secondary metabolites diversity and biological activities, and (iv)updating the traditional knowledge on medical uses, by adopting normalized and approved in vivo tests and standardized pharmacological methods to study the efficacy and mechanisms of action of extracts and bioactive molecules, and their cytotoxicity.