ENDOPHYTES FROM THE AQUATIC PLANT NELUMBO NUCIFERA: DIVERSITY PROFILE AND ACTIVITY CHARACTERIZATION
Objective: Endophytes represent a niche habitat for the study of novel bio-and chemo diversity. Nelumbo nucifera is an aquatic plant that has not been characterized for endophyte diversity. This study was undertaken with the objective of isolating endophytes from submerged and aerial part of N. nucifera, study the diversity profile of the isolated endophytes and their antimicrobial, antioxidant, and siderophore production capacity.
Methods: Endophytes were isolated from aerial and submerged parts of N. nucifera on different media (Starch Casein Nitrate, Glucose Yeast Extract, Nutrient and Potato Dextrose agar). These were further characterized for morphology (colony characteristics, Gram reaction), physiological characteristics (carbon, nitrogen utilization) and activity (antimicrobial, antioxidant, siderophore production). After dereplication, twelve isolates were studied further.
Results: All endophyte isolates were Gram-positive bacteria, and one was a fungus. Isolate L-300 showed the highest antioxidant capacity (238 AAE g FW-1) and L-201 least (10 AAE g FW-1. Antimicrobial activity was exhibited against bacteria and fungal targets, with 50% endophytes active against both bacteria and fungi. Isolates L-003 and L-207 exhibited activity against Gram-negative clinical isolates as also fungi. Siderophore production was shown by 58% isolates with L-208 showing maximum activity.
Conclusion: This is the first report on profiling of endophytes from N. nucifera. Results show that aquatic plants harbor diverse microbial population. Many promising isolates (such as L-003, L-211, L-214 and L-300) have been characterized in this study and results obtained of antioxidant, antimicrobial and siderophore production capacity demonstrate further utility in polypharmacological studies for identifying compounds of pharmaceutical and other industrial interest.
2. Tan RX, Zou WX. Endophytes: a rich source of functional metabolites. Nat Prod Rep 2001;18:448-59.
3. Saikkonen K, Faeth SH, Helander M, Sullivan TJ. Fungal endophytes: a continuum of interactions with host plants. Annu Rev Ecol Syst 1998;29:319-43.
4. Berdy J. Bioactive microbial metabolites. J Antibiot 2005;58:1-26.
5. Kredy HM, Huang DH, Xie BJ, He H, Yang, EN, Tian BQ, Xiao D. Flavonols of lotus (Nelumbo nucifera, Gaertn.) seed epicarp and their antioxidant potential. Eur Food Res Technol 2010; 231:387â€“94.
6. Mukherjee PK, Mukherjee D, Maji AK, Rai S, Heinrich M. The sacred lotus (Nelumbo nucifera)-phytochemical and therapeutic profile. J Pharm Pharmacol 2009;61:407-22.
7. Coombs JT, Franco CMM. Isolation and identification of actinobacteria from surface-sterilized wheat roots. Appl Environ Microbiol 2003;69:5603-8.
8. Tiwari S, Arya A, Kumar S. Standardizing sterilization protocol and the establishment of callus culture of sugarcane for enhanced plant regeneration in vitro. Res J Bot 2012;7:1-7.
9. Pridham TG, Gottlieb D. The utilization of carbon compound by some actinomycetes as an aid for species determination. J Bacteriol 1948;56:107-14.
10. Prieto P, Pineda M, Aguilar M. Spectrophotometric quantitation of antioxidant capacity through the formation of a phospho- molybdenum complex: specific application to the determination of vitamin E. Anal Biochem 1999;41:269-337.
11. Bauer AW, Kirby WMM, Sherris JC, Turck M. Antibiotic susceptibility testing by a standardized single disk method. Am J Clin Pathol 1966;45:493-6.
12. Velho-Pereira S, Kamat N. Antimicrobial screening of actinobacteria using a modified cross-streak method. Indian J Pharm Sci 2011;73:223-8.
13. Schwyn B, Neilands JB. Universal chemical assay for the detection and determination of siderophores. Anal Biochem 1987;160:47â€“56.
14. Chen WM, Tang YQ, Mori K, Wu XL. Distribution of culturable endophytic bacteria in aquatic plants and their potential for bioremediation in polluted waters. Aquat Biol 2012;15:99â€“110.
15. Barzanti R, Ozino F, Bazzicalupo M, Gabbrielli R, Galardi F, Gonnelli C, et al. Isolation and characterization of endophytic bacteria from nickel hyperaccumulator plant Alyssum bertolonii. Microb Ecol 2007;53:306-16.