Isolation of Mexican Bacillus Species and Their Effects in Promoting Growth of Chili Pepper (Capsicum annuum L. cv Jalapeño).

The purpose of this work was to isolate and identify native bacteria from plants collected in the State of Yucatán, México with the ability to promote growth of chili pepper (Capsicum annuum L. cv Jalapeño). We identified nine bacterial isolates that belong to five species of Bacillus (i.e. Bacillus subtilis, B. flexus, B. cereus, B. megaterium and B. endophyticus) that produced indoleacetic acid (4.0-24.3 µg/mL) with solubilization index of 1.3-1.6. All the bacterial isolates were evaluated based on their ability to promote growth of chili pepper. Plants inoculated with B. subtilis ITC-N67 showed an increase in stem diameter and root volume, whereas inoculation with B. cereus ITC-BL18 increased the number of flower buds, fresh biomass of roots and total fresh biomass. Conversely, B. flexus ITC-P4 and B. flexus ITC-P22 showed deleterious effect on root volume and total biomass. In summary, our data showed that native B. cereus TC-BL18 and B. subtilis ITC-N67 have potential to be used as growth promoting microorganism for chili pepper, particularly in the state of Yucatán, México.