Culturable endophytic bacteria from Phelipanche ramosa (Orobanchaceae) seeds

Endophytic microbiomes play a beneficial role in the development and protection of plants. However, seed-borne endophytic bacteria have not yet been fully explored. Investigation of parasitic plants, whose existence depends on yet poorly understood and complicated relationships with microorganisms and hosts, is particularly crucial. Endophytic bacteria promote seed conservation and facilitate seed germination in soil. Several root holoparasites from the Orobanchaceae family are the most aggressive broomrape species, often causing serious yield losses in important crops. Parasitic plants are characterized by the production of a large number of some of the smallest seeds in the world's flora, allowing them to stay viable in the soil for several dozen years. This study's aim was to isolate and characterize the seed endophyte and surface bacteria of the most aggressive and widespread broomrape weed, Phelipanche ramosa. We isolated two endophytic bacteria from within the seeds which are closely related to Brevibacterium frigoritolerans and Bacillus simplex described as soil bacteria, highly resistant to environmental conditions, and as plant growth-promoting rhizobacteria. Moreover, we isolated three strains from the surface of non-sterile seeds; all three isolates were related to the Bacillus cereus group.

Automated summary

Endophytic microbiomes play a key role in plant development and protection, with seed-borne endophytic bacteria being important but understudied. Investigating parasitic plants, particularly root holoparasites like broomrape species, is crucial due to their complex relationships with microorganisms and hosts. This study aimed to isolate and characterize seed endophyte and surface bacteria of the aggressive broomrape weed, revealing endophytic bacteria related to Brevibacterium frigoritolerans and Bacillus simplex within seeds, and Bacillus cereus group strains on non-sterile seed surfaces.