Plant-Growth-Promoting Traits of <i>Bacillus</i> Species Associated with Quinoa (<i>Chenopodium quinoa</i>) and Lambsquarters (<i>Chenopodium album</i>)

Abstract

As quinoa (Chenopodium quinoa Willd.) production expands globally, methods to mitigate abiotic and biotic production constraints are needed. One potential method to improve quinoa productivity is through the use of plant-growth-promoting microbes. In this study, we examined Chenopodium-associated Bacillus populations from Bolivia, Ecuador, and the United States for their ability to solubilize phosphate, antagonize Fusarium oxysporum, and produce phytase, indole acetic acid (IAA), and chitinase. The majority (99%) of isolates screened (n = 496) exhibited one or more traits related to plant growth promotion. Phosphate solubilization was observed in 75%, phytase production in 89%, IAA production in 44%, chitinase production in 13%, and antagonism to F. oxysporum in 8% of screened isolates. Some species or species groups screened were more likely than others to exhibit certain traits, such as B. megaterium, B. pumilus group, and B. subtilis group for phosphate solubilization and B. cereus group for chitinase production. This study indicates that many Chenopodium-associated Bacillus isolates exhibit plant-growth-promoting traits and could be studied further to promote quinoa production.