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Published on: February 3, 2017
Scanning electron microscopy reveals deleterious effects of Moringa oleifera seed exuded proteins on root-knot
Antônio J S Sousa1, Pedro F N Souza1, Juliana M Gifoni1
1Department of Biochemistry and Molecular Biology, Federal University of Ceara, Laboratory of Plant Toxins, Av. Mister Hull, P.O. Box: 60451, Fortaleza, CE, Brazil.
Abstract:
Plant seeds can exudate active molecules with inhibitory effects against several soil pathogens, including nematodes. This study aimed to characterize and evaluate the nematicidal properties against Meloidogyne incognita of exuded proteins from Moringa oleifera seeds. M. oleifera seeds were soaked in distilled water, and exudates were harvested and analyzed for the presence of defense proteins and anthelmintic activity. Enzymatic assays revealed the existence of PR-proteins such as β-1,3-glucanases (0.18 ± 0.003 nkatal mg-1 of protein), chitinases (0.22 ± 0.004 nkatal mg-1 of protein), proteases (261.30 ± 6.405 AU mg-1 of protein min-1), serine (190.30 ± 5.574 IA mg-1 of protein) and cysteine (231.70 ± 0.923 IA mg-1 of protein), protease inhibitors. The exuded proteins presented ovicidal activity and caused 100% mortality of second-stage juveniles (J2s). Scanning electron microscopy (SEM) revealed deleterious effects on M. incognita eggs, such as invaginations, cracks, scratched surface, and loss of internal content. These findings confirm the presence of anthelmintic proteins in M. oleifera seed exudate, possibly involved in plant defense during seed germination. Besides this, the exuded proteins exhibited strong biotechnological potential for use in the biocontrol of M. incognita infections, which are responsible for millions of dollars in staple crop losses every year.
Insights
Moringa oleifera seed exudates contain proteins with potent nematicidal activity against Meloidogyne incognita. These proteins show ovicidal effects and cause 100% mortality in juvenile nematodes, offering biocontrol potential.
Area of Science:
- Plant Pathology
- Biochemistry
- Agricultural Science
Background:
- Plant seeds can release molecules that inhibit soil pathogens like nematodes.
- Meloidogyne incognita causes significant annual crop losses globally.
Purpose of the Study:
- To characterize and evaluate the nematicidal properties of proteins exuded by Moringa oleifera seeds against Meloidogyne incognita.
Main Methods:
- Moringa oleifera seeds were soaked in water to collect exudates.
- Exudates were analyzed for defense proteins using enzymatic assays.
- Nematicidal activity was assessed against M. incognita eggs and juveniles.
- Scanning electron microscopy (SEM) was used to observe effects on nematode eggs.
Main Results:
- Enzymatic assays confirmed the presence of PR-proteins, including β-1,3-glucanases, chitinases, proteases, and protease inhibitors.
- The exuded proteins demonstrated ovicidal activity against M. incognita eggs.
- 100% mortality was observed in second-stage juveniles (J2s) of M. incognita.
- SEM revealed physical damage to nematode eggs, such as invaginations and surface cracks.
Conclusions:
- Moringa oleifera seed exudates contain anthelmintic proteins with significant nematicidal activity.
- These proteins may play a role in plant defense during seed germination.
- The findings highlight the potential of these exuded proteins for biocontrol strategies against Meloidogyne incognita.
