Chitin nanofibers trigger membrane bound defense signaling and induce elicitor activity in plants

• Published in: International journal of biological macromolecules Vol. 178; pp. 253 - 262
• Main Authors: Um-e-Aiman, Nisar, Numrah, Tsuzuki, Takuya, Lowe, Adrian, Rossiter, John T., Javaid, Arshad, Powell, Glen, Waseem, Rashad, Al-Mijalli, Samiah H., Iqbal, Munawar
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2021
• Subjects: Ball milling; Chitin based nanofibers; Crab and mushroom; Elicitor activity; Membrane triggering; Chitin based nanofibers; Ball milling; Membrane triggering; Elicitor activity; Crab and mushroom
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2021.02.164

The present study demonstrated that chitin-based nanofibers (CNFs) trigger the chitinase genes (PGIP1 and CaChi2), while elevating salicylic acid that can protect plants against pathogens. Cross-talk between this genetic induction and salicylic-acid-mediated immune response was also observed, which may arm a plant against multiple pathovars. Crab and mushroom based CNFs were synthesized by electrospinning and ball milling techniques. Plants (mung bean, Vigna radiata) (pepper, Capsicum annuum) were pre-inoculated with CNFs and treated with the pathogens Scrolotium rolfsii for pepper and Macrophomina phaseolina for mung bean and shrimp-based CNFs were used as a control. Treated plants had elevated levels of chitinase genes in response to CNFs at inoculation concentrations <10 mg/mL both in soil and media, to protect them against the pathogenic fungal disease. After 24 h of exposure to the pathogens, qRT-PCR showed genes class II chitinase gene (CaChi2) and polygalacturonase inhibitor protein 1 (PGIP1) to be up-regulated in both root and shoot at 0.1 and 1 mg/mL of inoculation, respectively. The ball milled mushroom CNFs were sufficient to trigger the membrane based enzymes with less diameter (≥15 nm) to be most efficient versus others. In vitro analysis showed IC50 of ball milled mushroom CNFs to be most efficient in limiting the growth of fungal biomass. Further trigger-like effects were prominent in reducing pathogenic fungal spread in both species.