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Biocontrol of the root‐knot nematode Meloidogyne incognita by a nematicidal bacterium Pseudomonas simiae MB751 with cyclic dipeptide
Author(s) -
Sun Xiaowen,
Zhang Run,
Ding Meijuan,
Liu Yongxuan,
Li Lin
Publication year - 2021
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.6470
Subject(s) - meloidogyne incognita , terra incognita , root knot nematode , biology , biological pest control , bioassay , horticulture , pseudomonas , fermentation , bacteria , nematode , botany , microbiology and biotechnology , food science , ecology , genetics
BACKGROUND Root‐knot nematodes (RKNs) are harmful plant‐parasitic nematodes that cause serious damage to plant hosts. In the long‐term practice of RKN management, bacterial nematicides have attracted increasing attention as an effective biocontrol means. Here we determined the active substances against Meloidogyne incognita from a nematicidal bacterium, developed a biocontrol agent (BCA) based on optimized culture processes. The effects of the BCA on RKN control and plant growth‐promotion were evaluated in tomato pot trials. RESULTS Pseudomonas simiae strain MB751 exhibiting significant nematicidal activity against M. incognita second‐stage juveniles (J2) with approximately 80% mortality (with culture supernatant, 96% volume percentage) was isolated from a vineyard. A set of purification and identification experiments was performed to determine the main nematicidal component in MB751. A cyclic dipeptide Cyclo(L‐Pro‐L‐Leu) was identified with a lethal concentration necessary to kill 50% of the population (LC 50 ) of 65.3 μg mL −1 against M. incognita J2. Following optimization trials on culture medium/fermentation conditions, such as the single factor test, Plackett–Burman test, steepest ascent, and response surface methodology experiments, the MB751 fermentation broth was then prepared as a BCA via a cold‐air drying process. The BCA and was evaluated in tomato pot experiments for effectiveness in suppressing M. incognita . Significant effects on M. incognita suppression and plant‐growth promotion as well as induced systemic resistance to M. incognita of tomato, were observed. CONCLUSION The cyclic dipeptide‐producing bacterium P. simiae MB751 exhibited high nematicidal activity and performance. Further development of this BCA should be pursued for the management of M. incognita in agriculture. © 2021 Society of Chemical Industry.