Isolation and identification of phloem sap endophytes from the lac host plants, <i>Flemingia</i> spp.

Background and purpose: Plants harbour mutualistic endophytes which are important for their growth and development. Lac host plant is the most important factor determining the lac yield because lac insects depend on the host for their nutrition and shelter throughout their life. Lac host endophytes could be postulated to impact lac insects positively. Hence, this study was attempted to explore the diversity of endophytic bacteria in the phloem sap of the lac host plants, Flemingia semialata and Flemingia macrophylla, and study their role in nutrient supplementation. Methods: Phloem sap was extracted from F. semialata and F. macrophylla and cultured on different nutrient-rich media. The colonies obtained were subjected to molecular identification by 16S rRNA gene sequencing. The colonies were also tested for IAA production, urea and zinc solubilization abilities. Results: It revealed that the isolates from F. semialata phloem sap to be Agrobacterium larrymoorei, Rhizobium sp., Sphingomonas sp., and Priestia aryabhattai whereas, the isolates from F. macrophylla to be Brevundimonas albigilva and Bacillus australimaris. The isolates also showed varied growth-promoting substance production and nutrient-solubilizing ability. Conclusion: For the first time, a few growth promoting bacterial endophytes were isolated from phloem sap of Flemingia spp.