AUTHOR=Adeleke Bartholomew Saanu , Ayangbenro Ayansina Segun , Babalola Olubukola Oluranti 

TITLE=In vitro Screening of Sunflower Associated Endophytic Bacteria With Plant Growth-Promoting Traits

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=6

YEAR=2022

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2022.903114

DOI=10.3389/fsufs.2022.903114

ISSN=2571-581X

ABSTRACT=<p>Harnessing endophytic microbes as bioinoculants promises to solve agricultural problems and improve crop yield. Out of fifty endophytic bacteria of sunflowers, 20 were selected based on plant growth-promoting. These plant growth-promoting bacteria were identified as <italic>Bacillus, Pseudomonas</italic>, and <italic>Stenotrophomonas</italic>. The qualitative screening showed bacterial ability to produce hydrogen cyanide, ammonia, siderophore, indole-3-acetic acid (IAA), exopolysaccharide, and solubilize phosphate. The high quantity of siderophore produced by <italic>B. cereus</italic> T4S was 87.73%. No significant difference was observed in the <italic>Bacillus</italic> sp. CAL14 (33.83%), <italic>S. indicatrix</italic> BOVIS40 (32.81%), <italic>S. maltophilia</italic> JVB5 (32.20%), <italic>S. maltophilia</italic> PK60 (33.48%), <italic>B. subtilis</italic> VS52 (33.43%), and <italic>P. saponiphilia</italic> J4R (33.24%), exhibiting high phosphate-solubilizing potential. <italic>S. indicatrix</italic> BOVIS40, <italic>B. thuringiensis</italic> SFL02, <italic>B. cereus</italic> SFR35, <italic>B. cereus</italic> BLBS20, and <italic>B. albus</italic> TSN29 showed high potential for the screened enzymes. Varied IAA production was recorded under optimized conditions. The medium amended with yeast extract yielded high IAA production of 46.43 μg/ml by <italic>S. indicatrix</italic> BOVIS40. Optimum IAA production of 23.36 and 20.72 μg/ml at 5% sucrose and 3% glucose by <italic>S. maltophilia</italic> JVB5 and <italic>B. cereus</italic> T4S were recorded. At pH 7, maximum IAA production of 25.36 μg/ml was obtained by <italic>S. indicatrix</italic> BOVIS40. All the isolates exhibited high IAA production at temperatures 25, 30, and 37°C. The <italic>in vitro</italic> seed inoculation enhanced sunflower seedlings compared to the control. Therefore, exploration of copious endophytic bacteria as bioinoculants can best be promising to boost sunflower cultivation.</p>