@article { author = {Abdellatif, Aya Abdalrahman Mohamed and Abd-Elrahman, Tahany Mohamed Ali and Sayed, Mohsen Abou Elela and Ragab, Atef Abd El-Aziz Hassan and Ibrahim, Dina Salah-Eldin Serag-Eldin}, title = {Isolation, Identification and Biocontrol Activity of Novel Chitinolytic Bacteria against Meloidogyne incognita Infecting Capsicum annuum L.}, journal = {Caspian Journal of Environmental Sciences}, volume = {21}, number = {1}, pages = {49-68}, year = {2023}, publisher = {University of Guilan}, issn = {1735-3033}, eissn = {1735-3866}, doi = {10.22124/cjes.2023.6195}, abstract = {In the era of climate change, environmental degradation caused by the unabated and indiscriminate usage of synthetic nematicides, there is urgent demand to develop safe alternatives for management of nematode diseases.  In this respect, this study aimed to isolate, characterize, and evaluate novel chitinolytic rhizobacteria as biocontrol agents against Meloidogyne incognita infecting Capsicum annuum L.  Among seventeen chitinolytic bacterial isolates, which were isolated from nematode suppressive soil, five isolates exhibited high chitinolytic activity. These isolates were identified based on 16S rRNA gene analysis as Chryseobacterium daecheongense (isolate AB1), Bacillus toyonensis (isolate AB2), Pseudomonas lini (isolate AB3), Lactobacillus helveticus (isolate AB4) and Klebsiella oxytoca (isolate AB5). In vitro studies revealed that maximum nematode mortality (100%) was recorded for isolates AB3 and AB5; while maximum egg hatching inhibition (90.86 and 86.27%) in AB3 and AB4, respectively. Under field conditions, maximum inhibition in gall formation, female numbers, egg-mass production, developmental stages and final population of juveniles in soil, was recorded for AB3, AB4 and AB5 isolates, respectively. The accumulation of phenolic compounds, peroxidase and polyphenol oxidase in pepper leaves were induced by different bacterial treatment which played a significant role in resistance of the plant to biotic stress. The histological study showed poor formation of regular giant cells in pepper roots treated with chitinolytic bacterial strains. Root transverse section of pepper plants infected with M. incognita and treated with isolates AB3 and AB4 showed maximum healthy pattern and less necrotic points compared to the control. In conclusion, this study demonstrated that among the tested bacterial stains, P. lini (AB3), L. helveticus (AB4) and K. oxytoca (AB5) showed high biocontrol prospects against M. incognita and could be introduced and formulated as a promising, affordable and safe bionematicides. Moreover, C. daecheongense (AB1) was recorded for the first time for its nematicidal activity.}, keywords = {Rhizobacteria,Chitinase,biological control,Meloidogyne incognita,Capsicum annuum L}, url = {https://cjes.guilan.ac.ir/article_6195.html}, eprint = {https://cjes.guilan.ac.ir/article_6195_5b78920655db3cb02254588eb795b59f.pdf} }