Curcumin Derived Nanoscale Coordination Polymers for Modulating Stress Response in Plants

<b>Aim/Introduction:</b><br/>Different stressing factors (e.g. drought, viral infection, insects, etc.) can impose significant survival threats to plants, especially in agricultural scenarios. Strategies to alleviate these stress burdens are able to improve plant physiology and adapt them to more “unfriendly” environment. Nanotechnology is a rising star to ameliorate plant stress situation. The goal of this study is to develop a curcumin-metal coordination nanoplatform with intrinsic protecting capacity against various stressing factors in chosen plants (Arabidopsis thaliana and wheat selected as the patients), and it can simultaneously deliver therapeutic cargos to further improve plants survival against various stressing factors.<br/> <br/><b>Materials and Methods:</b><br/>Curcurmin (Cur) was reacted with manganese acetate or zinc acetate by a solvothermal method to form porous nanostructures. X-ray diffraction analysis revealed the crystal structures from both Cur-Mn and Cur-Zn. The morphology, stability, and other physical properties from Cur-Mn and Cur-Zn were also evaluated. The biocompatibility of Cur-Mn/Cur-Zn was tested in Arabidopsis thaliana and wheat cells and plants. Subsequently, the biological impacts of Cur-Mn/Cur-Zn along with their distribution profiles in these plants were measured post the spay of a suspension of 50 μg/mL. The cargo accommodating and releasing capacity was tested for fludioxonil, a broad-spectrum bacteria and fungi killing molecule. Finally, the molecular mechanisms of Cur-Mn/Cur-Zn for stress resistance in these two plants were also explored.<br/> <br/><b>Results:</b><br/>Cur-Mn and Cur-Zn had a size range of 60-90 nm (measured by TEM) with good dispersity and production yields. In their structures, curcumin was coordinated with manganese/zinc to form framework structures. Cur-Mn and Cur-Zn could be internalized into Arabidopsis thaliana and wheat cells with no noticeable toxicity. Once applied in the plant leaves, these materials could be absorbed quickly and transported via vessels inside plant stem, and reached the roots and other plant parts in a timely manner. Pure Cur-Mn and Cur-Zn could add the drought resistance capacity to these plants, and the molecular mechanisms were clarified by RNA-seq techniques. Moreover, Cur-Zn could accommodate more than 40%w/w of fludioxonil, and protect it from UV degradation. Once applied in the field of wheat, fludioxonil@Cur-Zn could protect wheat plants from fusarium blight in a more persistent manner.<br/> <br/><b>Conclusion:</b><br/>As a natural compound from the plant, curcumin can coordinate with different metals to form nanosized materials, and our findings revealed that this “from plant, to plant” strategy could be an efficient tool to protect plants from multiple critical stress factors, broadly applicable in plant rescue.