Role of Bacterial Endophytes Associated with Seaweed Species in Nourishing Mexican Lime Seedlings in South of Iran

Bacterial endophytes associated with algae represent a rich source of bioactive metabolites and biostimulants that can be used practically in agriculture as biofertilizer. We carried out a series of experiments to study the diversity of bacterial endophytes associated with seaweed species of the Persian Gulf (PG) and Oman Sea (OS) and their capability in nourishing Mexican lime seedlings. We collected samples of brown, red, and green seaweed species (۶۲ samples of brown, ۷۹ of red and ۴۹ of green) from intertidal zones of PG and OS in southern coastlines of Iran. The isolated bacteria were identified molecularly, morphologically and physiologically. Among ۱۲ bacterial genera identified, the genus Bacillus had the highest frequency (۵۱.۵۱%). In addition to identification, results showed that all bacterial endophytes isolates were negative oxidase, most isolates (۸۱.۲۵ ­%) were positive catalase and could produce HCN, and all isolates produced IAA, from ۰.۸۹۷ μg mL-­۱ in Empedobacter falsenii to ۰.۰۸۵ μg mL-۱ in Bacillus zhangzhouensis. Most isolates (۹۶.۷۷%) were able to grow on medium incorporated with different NaCl concentrations. Results of inoculation showed that lime seedlings colonized by B. aquimaris (MT۲۷۸۲۶۰), B. megaterium (MN۶۲۶۶۳۱) and B. zhangzhouensis (MN۶۱۱۳۵۹) had more growth and intended morphological characteristics than those lacking endophytes.

Keywords:

Endophytic bacteria , HCN test , IAA test , Microbial biofertilizer.