Biomolecule repository of endophytic bacteria from guava serves as a key player in suppressing root- knot nematode, Meloidogyne enterolobii

Guava production in India is hampered by invasion of guava root knot nematode, Meloidogyne enterolobii. Biological control of plant parasitic nematodes is the best strategy to quench the soil and root population of nematodes. Hence the attempts were made to dissect the endophytic bacteria from various niche of guava plants. Amongst the various endophytic bacteria's, Klebsiella quasivaricola inhibited the egg hatching (100%) and moratlity of juveniles (100%). Exploration of non-volatile organic compounds of K. quasivaricola exhibited the presence of 2 ''-terthiophene, 9 ' spirobifluorenone, 4-Cyanophenyl 4-butylbenzoate, Benzoic acid, Benzoyl chloride, 3-phenyl-1, 2, 4-triazolin-5-one, Ethanone, 2,3-dihydro-5-methoxy-, Ethanone, Trifluoroacetophenone, 6,12-dinaphthylindolo[3,2-b] carbazole having anti-microbial activities. Considering this, molecular docking experiments were carried out with important proteins of M. enterolobii such as Translationally Controlled Tumour Proteins, pectate lyase, phospholipase, hexokinase and Sphingomyelinase to understand the effect of biomolecules from K. quasivaricola. The results indicated that all biomolecules had prominent effect on different protein targets and in specific binding affinity with amino acid residues of protein targets benzoic acid, 4-Cyanophenyl 4-butylbenzoate, Trifluoroacetophenone, 6,12-dinaphthylindolo[3,2-b]carbazole, 3-phenyl-1,2,4-triazolin-5-one had significant effect on aforementioned protein targets of M. enterolobii. In addition, biohardened guava plants with the effective bacterial endophytes were challenged with M. enterolobii showcased 80% increase on plant growth parameters and 70% reduction of egg mass over control. Hence the present study gave limelight to explore the novel biomolecules from endophytic bacterium which could serve as an alternative synthetic nematicides for the management of M. enterolobii.

Automated summary

This study isolated an endophytic bacterium Klebsiella quasivaricola from guava plants, which inhibits the guava root knot nematode and produces compounds that have a significant effect on key proteins of the nematode. Biohardened guava plants treated with this bacterium showed a 80% increase in plant growth parameters and a 70% reduction in egg mass of the nematode.