Rice sprout endophytic Enterobacter sp. SE-5 could improve tolerance of mature rice plants to salt or Cd2+ in soils

Artificial selection of inheritable endophytic bacteria can elucidate bacterial functions that alter host performance. The inheritable bacteria can transmit from seeds to sprouts and mature plants despite of exterior environmental changes. The aim of this study was to investigate the effects of inheritable bacteria on tolerance of rice under stresses of salt or Cd2+. The inheritable endophytic Enterobacter sp. SE-5 was isolated from rice sprouts and inoculated with rice seeds during germination. Transmission of SE-5 within mature rice plants and soils was studied. Results showed that SE-5 inoculation resulted in a significant increase in biomass of mature plants under the stresses. The inoculated strain SE-5 tagged with the gfp could be transmitted into rhizosphere soil, and roots, stems, and leaves of mature plants. Enterobacter sp. SE-5 could survive in different soil layers for > 90 d. The results suggested that the sprouts germinated under aseptic conditions contained inheritable endophytic bacteria, and the inheritable bacteria could proliferate and transmit in mature plants and rhizosphere soil during plant growth. As a feasible inoculation method, seed coating can be adopted to inoculate plants in rhizosphere microbiome engineering.