Management strategies and resistance of almond rootstocks against Agrobacterium tumefaciens

Crown gall, caused by Agrobacterium tumefaciens , is a persistent challenge to almond ( Prunus dulcis ) cultivation, threatening orchard productivity worldwide. This review critically examines the current understanding of the pathogen, the vulnerability of almond rootstocks, and the mechanisms of natural and induced resistance. We summarize conventional management approaches alongside advances in molecular breeding and biotechnology, with an emphasis on tools such as marker-assisted selection, RNAi-based gene silencing, and CRISPR/Cas genome editing. Screening methods and breeding strategies are also assessed to identify pathways for integrating resistance traits into elite rootstocks. Collectively, the synthesis highlights that durable resistance will require coordinated programs combining resistant germplasm, biotechnological innovation, and integrated disease management. By outlining these opportunities, this review provides a framework to guide breeding and orchard management toward sustainable solutions for crown gall in almonds.