Natural Chemicals from Infected Insects for Controlling Harmful Plant Parasites

Jim Crocker
30th June, 2024

Natural Chemicals from Infected Insects for Controlling Harmful Plant Parasites

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Nankai University found that VOCs from cadavers infected by certain nematodes can kill root-knot nematodes (RKNs)
  • VOCs from Steinernema feltiae and S. carpocapsae were particularly effective in killing the juvenile stage of RKNs
  • The compound DMDS, identified in the VOCs, not only killed RKNs but also stopped their eggs from hatching and reduced their invasion of tomato roots
Root-knot nematodes (RKNs), specifically Meloidogyne spp., are one of the most destructive plant-parasitic nematodes, posing a significant threat to global food security. These nematodes are notoriously difficult to control, necessitating new and effective management strategies. Recent research conducted by Nankai University[1] has investigated an innovative approach involving volatile organic compounds (VOCs) emitted from entomopathogenic nematode (EPN)-infected cadavers to control RKNs. This study offers promising insights into sustainable pest management. The study aimed to examine whether VOCs emitted from cadavers infected by five different EPN species could control RKNs. The researchers found that VOCs from Steinernema feltiae (SN strain) and S. carpocapsae (All strain) infected cadavers had a significant lethal effect on the second-stage juveniles (J2s) of Meloidogyne incognita. Further analysis using solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC/MS) identified several VOCs from S. feltiae-infected cadavers, including dimethyl disulfide (DMDS), tetradecane, pentadecane, and butylated hydroxytoluene (BHT). Validation experiments revealed that DMDS had significant nematicidal activity, repelled J2s, inhibited egg hatching, and reduced the invasion of tomato roots by J2s. The findings of this study build on previous research highlighting the challenges of managing plant-parasitic nematodes in agricultural systems. For instance, a review of nematode challenges in Sub-Saharan Africa (SSA) emphasized the need for holistic pest management approaches, particularly under intensified crop production systems[2]. Another study underscored the economic importance of various nematode species, including root-knot nematodes, and the need for effective management strategies[3]. Traditional chemical nematicides have been largely banned due to their environmental and health impacts, and there is a pressing need for alternative solutions[4]. Biological control methods, including the use of nematophagous microbes, have shown potential as sustainable alternatives[5]. The current study by Nankai University contributes to this body of knowledge by demonstrating the potential of EPN-infected cadaver VOCs in controlling RKNs. The researchers conducted a series of experiments to evaluate the fumigation activity of these VOCs. In Petri dish assays, VOCs from S. feltiae and S. carpocapsae infected cadavers were found to be highly effective in killing J2s of M. incognita. The identification and validation of DMDS as a potent nematicidal compound further supported the potential of this approach. DMDS not only killed J2s but also inhibited egg hatching and reduced root invasion, addressing multiple life stages of the nematode. In addition to laboratory experiments, the researchers conducted a pot experiment to assess the practical applicability of their findings. They added S. feltiae-infected cadavers, both directly and wrapped in a 400-mesh nylon net, to tomato plants infested with RKNs. After seven days, the population of RKNs in the tomato roots was significantly reduced. The number of root knots and eggs decreased by 58% and 74.34%, respectively, compared to the control group. These results suggest that VOCs emitted by EPN-infected cadavers can effectively control RKNs through multiple methods, including direct nematicidal activity, repelling nematodes, inhibiting egg hatching, and reducing root invasion. This approach offers a promising alternative to traditional chemical nematicides, aligning with the need for sustainable and environmentally friendly pest management strategies. In summary, the study conducted by Nankai University provides compelling evidence that VOCs from EPN-infected cadavers can be used to control root-knot nematodes. This innovative approach addresses the need for effective and sustainable pest management solutions, particularly in regions like SSA where nematode infestations pose significant challenges to agricultural productivity[2]. The identification of DMDS as a key nematicidal compound offers a new avenue for developing biocontrol methods that can mitigate the impact of these destructive pests on global food security.

AgricultureEnvironmentBiotech

References

Main Study

1) Volatile organic compounds released from entomopathogenic nematode-infected insect cadavers for the biocontrol of Meloidogyne incognita.

Published 29th June, 2024

https://doi.org/10.1002/ps.8268

Related Studies

2) Plant-Parasitic Nematodes and Food Security in Sub-Saharan Africa.

https://doi.org/10.1146/annurev-phyto-080417-045833

3) Top 10 plant-parasitic nematodes in molecular plant pathology.

https://doi.org/10.1111/mpp.12057

4) Rhabdopeptides from Xenorhabdus budapestensis SN84 and Their Nematicidal Activities against Meloidogyne incognita.

https://doi.org/10.1021/acs.jafc.8b00253

5) Signal pathways involved in microbe-nematode interactions provide new insights into the biocontrol of plant-parasitic nematodes.

https://doi.org/10.1098/rstb.2018.0317


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