Bacillus haynesii WVC18 as a sustainable and eco-friendly solution for agricultural application

An increasing need for a more sustainable agriculturally-productive system is required in order to preserve soil fertility and reduce soil biodiversity loss. The Farm to Fork Strategy, published in May 2020 by the European Union, supports the transition to a more sustainable, productive system in which the dependency on pesticides, antimicrobials, and over-fertilization will be drastically reduced. The rhizosphere and its microbial community have a fundamental role in the development of healthy relations with soil and plants. Members of Bacillus spp. have been widely used to enrich soil/root interface to provide plant growth promoting activities. A new isolate, Bacillus haynesii VWC18 (Patent N°102023000006816) has been tested in greenhouse, in lettuce (Lactuca sativa L.) pots at different concentrations and application time (single and multiple inoculum) to evaluate the best application mode. Analysis of foliar fresh/dry weight and nutrient uptake evidenced a significant response of all applications. The lowest and the highest doses, applied every ten days until harvest, were the most effective; the nutrients yield (N, K, P, Na, Ca, Fe, Mg, Mn, Cu and B) increased more than twice. A new randomized block design with three replicates was then performed in lettuce and basil (Ocinum basilicum L.) with the two best performing concentrations applied every ten days. In addition to previous analyses, roots weight and photosynthetic pigments concentration were also examined. Both experiments confirmed the efficacy of the inoculum; the administration of Bacillus haynesii VWC18 promoted plant growth, chlorophyll and mineral uptake in both crop species. Roots weight duplicated or triplicated compared to control plants; the chlorophyll concentration increased as well. Both parameters showed a dose-dependent increase. B. haynesii WVC18 is a promising biological tool to improve nutrients bio-availability and increase crop yield