How plants recognize nematodes: Signal and signalling
Final Report Abstract
Here we report a comprehensive study into basal immunity by nematodes. Characterization of NILR1 as the first ever reported nematode PRR is a broad step towards understanding PTI in plants induced by nematode. NILR1 was also confirmed to be conserved in both monocots and dicots plants. Furthermore, we identified other nematodes specific defense related genes in Arabidopsis(CRK19; NEK5; NILR3), that are currently been studied in detail to fully understand their role in the recognition process. We show that NemaWater contain elicitor molecules which are proteinaceous in nature. Analysis of NemaWater fraction by SDS-PAGE and Tandem liquidchromatography mass-spectrometry revealed the presence of nematode protein molecules. Interestingly, nematode surface coat proteins were also represented in the data. Several of these proteins have been reported in animal-parasitic nematode host interaction to have immunogenic properties. We assumed that at least one or more of the nematodes surface expressed/localized proteins detected in NemaWater are recognized by the plant immune system to activate defense responses. For example enolase a cytosolic metalloenzyme responsible for the conversion of 2-phosphoglycerate into phosphoenolpyruvate, the second to last step in glycolysis was highly abundant in NemaWater. Enolase is considered as a ‘moonlighting protein’ due to its multiple functions aside from its involvement in glycolysis. Currently no information is available regarding the role of enolase in plant immune modulation. Other interesting nematode conserved molecules such as heat-shock proteins (HSP) and cuticular collagen, were also abundance in NemaWater. This study shows that plants are able to recognize nematode through an unknown conserved protein molecule. A follow-up project, which is currently in the application process, will focus on characterizing in detail these nematode-derived proteins identified in HsNemaWater and finally molecular patterns (motives) involved in eliciting plant defence. This will provide useful information for the reinforcement of PTI, for example through triggering of induced resistance or genetic engineering hence, providing an important strategy to generate field crops with broadspectrum resistance.
Publications
- (2017). Arabidopsis leucine-rich repeat receptor–like kinase NILR1 is required for induction of innate immunity to parasitic nematodes. PLoS Pathogens, 13(4), e1006284
Mendy, B., Wang’ombe, M. W., Radakovic, Z. S., Holbein, J., Ilyas, M., Chopra, D., Holton, N., Zipfel, C., Grundler, F.M.W., Siddique, S.
(See online at https://doi.org/10.1371/journal.ppat.1006284) - (2017). Damage-associated responses of the host contribute to defence against cyst nematodes but not root-knot nematodes. Journal of Experimental Botany, 68(21-22), 5949-5960
Shah, S. J., Anjam, M. S., Mendy, B., Anwer, M. A., Habash, S. S., Lozano-Torres, J. L., Grundler, F.M.W., Siddique, S.
(See online at https://doi.org/10.1093/jxb/erx374) - (2018). Parasitic nematodes manipulate plant development to establish feeding sites. Current Opinion in Microbiology, 46:102-108
Siddique, S., Grundler, F. M. W.
(See online at https://doi.org/10.1016/j.mib.2018.09.004)
