Endophytic Bacterial Consortium Originated from Forestry Plant Roots and Their Nematicidal Activity against Meloidogyne incognita Infestation in Greenhouse

Abstract

Yield loss due to root-knot nematode Meloidogyne incognita infection is reported to reach 35%, depends on factors contributing to infection. Application of several endophytic bacterial isolates (bacterial consortium) to control pathogenic infection is reported to be more effective compared to the application of single bacterial isolate. This study was aimed to obtain endophytic bacterial consortium originated from forestry plant that is effective to control root-knot nematode. The study was conducted through bacterial isolation followed by biosafety test. Bacterial isolates that were found to be safe for plants and mammals and compatible with each other were further grouped as the endophytic bacterial consortium. Phenotypic characterization and physiological characteristics including Gram type, ability to produce protease, chitinase, and lipase enzymes as well as HCN volatile compound were also tested. Moreover, the ability to fix nitrogen and dissolve phosphate were also examined. The endophytic bacterial consortium consisted of several bacterial isolates was further tested for its ability to inhibit M. incognita egg hatching and increase J2 of M. incognita mortality in vitro. Furthermore, test on tomato plants infested with 500 J2 of M. incognita was also performed in the greenhouse. Test results showed that 70 bacterial isolates were successfully isolated from Shorea sp., Swietenia sp., Albizia falcataria, Anthocephalus cadamba, and Juglans nigra. However, 34 bacterial isolates were observed to be safe (did not cause hypersensitivity reaction and did not produce hemolytic toxin). According to physiological characteristics, it was found that 25 isolates were able to produce protease enzyme, 26 isolates were able to produce chitinase enzyme, and 14 isolates were able to produce lipase enzyme. Moreover, it was also detected that 11 isolates were able to produce HCN volatile compound, 23 isolates were able to fix nitrogen (N), and 24 isolates were able to dissolve phosphate (P). Endophytic bacterial consortium obtained in this study was also observed to be able to inhibit M. incognita egg hatching up to 81.33% and increase J2 of M. incognita mortality up to 85% compared to control. In addition, the application of endophytic bacterial consortium was also able to increase the growth of tomato plant infected with M. incognita, and suppress the severity of the root-knot disease. This study provided information that endophytic bacterial consortium originated from forestry plants has the potential as a biocontrol agent of M. incognita.

Cost-effective bacteria-based bionematicide formula to control the root-knot nematode Meloidogyne spp. on tomato plants

“…Data were analyzed using Analysis of Variance (ANOVA), if there was a difference, the analysis was continued using a continuous test following the Duncan Multiple Range Test (DMRT) method with 95% degree of confidence. The analysis was performed using the DSAASTAT version 1.101 program (Munif et al 2019).…”

Bacteria as Biocontrol Tool against Phytoparasitic Nematodes

“…Many reports have shown that PGPB can promote plant growth and enhance yield from plants affected by nematodes under greenhouse, microplot and field conditions [ 6 , 22 , 43 , 55 , 56 , 57 , 58 , 59 , 60 ]. A microplot experiment was carried out in the National Agriculture Research Center (Tsukuba, Japan) on low-humic and M.incognita infested soil to ivestigate the nematicidal effects of Pasteuria penetrans .…”

Fungal and Bacterial Endophytes as Microbial Control Agents for Plant-Parasitic Nematodes

“…Metabolites of both bacteria reduced the number of egg masses and root galls, while P. protegens also promoted seed germination and plant growth. In another study, Munif et al [ 78 ] obtained 81% mortality of J2s and 81% reduction in egg-hatch of M. incognita with a consortium of bacterial endophytes isolated from trees. Details of these endophytic species were not revealed, however.…”

“…Some consider that a consortium of beneficial microorganisms is better than using a single microorganism and several commercial products based on microbial consortia have been developed in the recent years [ 78 , 91 ]. However, consortia may not always provide better control than a single endophyte due to potential negative interactions among the members.…”