Biocontrol of the root-knot nematode Meloidogyne incognita by a nematicidal bacterium Pseudomonas simiae MB751 with cyclic dipeptide.

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. 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 (LC50 ) 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. 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.

Sun X ，Zhang R ，Ding M ，Liu Y ，Li L ... -  《-》

Phenylacetic acid-producing Rhizoctonia solani represses the biosynthesis of nematicidal compounds in vitro and influences biocontrol of Meloidogyne incognita in tomato by Pseudomonas fluorescens strain CHA0 and its GM derivatives.

Siddiqui IA ，Shaukat SS 《JOURNAL OF APPLIED MICROBIOLOGY》

3-(Methylthio)Propionic Acid from Bacillus thuringiensis Berliner Exhibits High Nematicidal Activity against the Root Knot Nematode Meloidogyne incognita (Kofoid and White) Chitwood.

Chen L ，Wang Y ，Zhu L ，Min Y ，Tian Y ，Gong Y ，Liu X ... -  《INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES》

Biocontrol Efficacy of Bacillus methylotrophicus TA-1 Against Meloidogyne incognita in Tomato.

Liu H ，Fu G ，Li Y ，Zhang S ，Ji X ，Qiao K ... -  《-》

Identification for the First Time of Cyclo(d-Pro-l-Leu) Produced by Bacillus amyloliquefaciens Y1 as a Nematocide for Control of Meloidogyne incognita.

Jamal Q ，Cho JY ，Moon JH ，Munir S ，Anees M ，Kim KY ... -  《MOLECULES》