Title : Isolation and identification of plant probiotics for leafy greens
Abstract:
Plant probiotic bacteria are plant-associated microorganisms that, when applied in a specific amount, improve the growth and yield of the host plants while also suppressing diseases. These plant probiotics have been shown to improve the production of phytohormones, antibiotics, and lytic enzymes; fix atmospheric nitrogen; and even help in the solubilization of soil mineral nutrients (Rahman et al., 2018). Major general of probiotic bacteria that promote plant growth include Bacillus, Pseudomonas, Acinetobacter, Arthrobacter and Serratia (Rahman et al., 2018). One example of these probiotics being able to increase the yield of the plant is in strawberries, where the bacteria species Bacillus amyloliquefaciens and Paraburkholderia fungorum increased both the size of the fruits as well as the quantity of the leaves and roots (Rahman et al., 2018). Another example would be broccoli, where the inoculation of PGPR bacteria (Bacillus cereus, Brevibacillus reuszeri and Rhizobium rubi) had shown an increment in chlorophyll, N, K, Ca, S, P, Mg, Fe, Mn, Zn and Cu contents. Crop yield increased by 17%, 20.2%, and 24.3% and chlorophyll content by 14.7%, 14.0% and 13.7% in treatments added with Bacillus cereus, Brevibacillus reuszeri and Rhizobium rubi, respectively (Rahman et al., 2018). In addition, some PGPR strains are effective in suppressing pest, pathogen and effective as biocontrol agents. Study reported that various Bacillus strains are important in controlling pathogens and improving plant growth due to antagonistic relationships (Rahman et al., 2018). A previous study also showed that PGPR is involved in the production of plant hormones such as indole acetic acid (IAA). The bacteria species most studied and likely to produce this compound are Bradyrhizobium japonicum SB-1 and Bradyrhizobium thuringiensis (Asghari et al., 2020). This study determined the reproducibility of using three plant probiotics strains (Isolate 4 (Acinetobacter pittii), Isolate 9 (Bacillus altitudinis), and Isolate 8 (Bacillus licheniformis)) on the plant growth of curly kale, Jericho lettuce and Thai basil seeds.
