Lentil Landrace Seed Origin and Genotype Affects Rhizosphere Microbiome

Lentil (Lens culinaris Medik.) is an essential legume crop providing healthy and nutritious food for people in low- to middle-income countries, worldwide. Lentil roots support symbiotic interactions with soil rhizobia species fostering nitrogen fixation; however, assemblage and diversity of the complete microbial rhizosphere community and the effect of seed genotype and origin remain largely unexplored. In this study we examined, via metagenomic analysis, the effects of seed origin on the rhizosphere's communities in samples of the famous Greek lentil landrace, Eglouvis, derived from different local farmers and farming systems (including a Gene Bank sample), in comparison to a commercial variety. The landrace exhibited higher rhizosphere microbiome diversity compared to the commercial variety for all indexes. A core microbiome comprised of 158 taxa was present in all samples, while a greater number of unique bacterial taxa was recorded in the landrace samples compared to the commercial cultivar. Notably, landrace samples originated from organic farming had more than double the number of unique taxa compared to conventional counterparts. The study revealed a higher diversity of N-2 fixers and archaea, Crenarchaeota and Thaumarchaeota, in landrace samples and particularly in those derived from organic farming, underpinning the distinct recruiting efficiency of beneficial soil microbes by the landrace.