Comparative metagenomic analysis of bacterial and fungal communities associated with bayoud-resistant and susceptible date palm cultivars in the Zagora oasis-Morocco

Fusarium oxysporum f. sp. albedinis (Foa) is a destructive soil-borne fungal pathogen responsible for bayoud disease, which threatens date palm cultivation in North Africa. This disease has caused significant agricultural losses, particularly in Morocco, where the Zagora oasis is a key region for date palm production. Within this oasis, two cultivars—Black Bousthammi and Jihel—are mainly cultivated and exhibit complete resistance and high susceptibility to Foa, respectively. Thus, this study aimed to identify and compare the bacterial and fungal communities associated with the two cultivars and understand their assemblage regarding the disease resistance or susceptibility. Moreover, we explored the influence of each cultivar on the composition and structure of its root-associated microbiome and examined its relationship with the microbial populations present in the surrounding bulk soil, to better understand the recruitment dynamics that shape the microbiome in the roots. The results revealed significant differences in microbiome composition between the bulk soil and roots of the two date palm cultivars, and between the microbiome of the resistant and susceptible cultivars as well. Moreover, we observed that date palm cultivars had a greater effect on bacterial community composition than on fungal population. Interestingly, the susceptible cultivar exhibited a higher enrichment of several beneficial genera, such as Pseudomonas, Lysinibacillus, Actinomadura, Halomonas, Kocuria, Serratia, Phyllobacterium, Bacillus, Streptomyces, and Trichoderma. The presence of these beneficial genera, known for their antagonistic activity against phytopathogens, may reflect a recruitment pattern associated with pathogen pressure in the susceptible cultivar. This study is the first to compare the microbial communities between a bayoud-resistant and susceptible cultivar and provides insights into the potential role of the root microbiome when plants are under pathogen pressure. This reinforces the need to further elucidate the genetic and biological mechanisms that trigger microbiome assembly, which could be a key step in developing effective methods to manage the bayoud disease.