論文研究了生理環(huán)境下MONPs是否具有清除活性氧的能力，在體外模擬了多種活性氧環(huán)境用于評估MONPs的抗氧化活性。結(jié)果表明MONPs具有多種類酶活性，具有廣譜的活性氧直接清除功能。圖2解析了MONPs在柑橘葉組織中的內(nèi)化和分布情況：通過透射電子顯微鏡對噴灑和滲透MONPs的柑橘葉片進行精細掃描，可觀察到大量的MONPs特征性納米花結(jié)構(gòu)定位于細胞壁周圍的細胞外間隙，表明MONPs能夠被柑橘葉有效吸收。這種基于MONPs的遞送系統(tǒng)有望為解決柑橘和其他植物的遞送問題提供一種更有效且環(huán)保的替代方法。
通過研究MONPs在柑橘體內(nèi)的抗氧化機制，結(jié)果表明，MONPs處理展現(xiàn)出對患病柑橘中氧化防御相關(guān)基因表達和酶活性等顯著的正調(diào)控，從而通過間接的抗氧化途徑減輕CLas侵染所引起的脅迫。圖3展現(xiàn)了MONP處理是否能夠預(yù)防和保護柑橘免受黃龍病感染，通過對黃龍病感染初期的柑橘進行MONPs對長期處理，表明MONPs可通過抗氧化作用有效緩解黃龍病的相關(guān)癥狀。圖4結(jié)果顯示，MONPs處理后大幅改善了患病柑橘中相關(guān)生理指標，相關(guān)基因表達和酶活性，展現(xiàn)了對患病柑橘生長的有效保護。
綜上，這種基于錳基納米酶（MONPs）的防治策略，多功能、高穩(wěn)定性和易于批量制備，可通過葉片噴霧和注射等施用方式有效地內(nèi)化進患病柑橘內(nèi)部，減輕氧化損傷，保護植物組織并緩解黃龍病癥狀。有潛力拓展納米材料在柑橘黃龍病防治中的應(yīng)用，服務(wù)于柑橘產(chǎn)業(yè)的發(fā)展。
本文的第一作者為生命科學(xué)技術(shù)學(xué)院博士研究生李爍鈞（現(xiàn)中國科學(xué)院分子細胞卓越創(chuàng)新中心博士后）與化學(xué)學(xué)院碩士研究生龍玉瀅，通訊作者為我校韓鶴友教授。該研究得到國家重點研發(fā)計劃項目（2021YFD1400803）的資助。
【英文摘要】
Huanglongbing （HLB） is a severe disease in Citrus caused by the infection ofCandidatusLiberibacter asiaticus （CLas）， which has brought about substantial economic losses in the global Citrus industry. Recently, HLB has been recognized as a plant immune-mediated disease resulting from theCLas-colonization stimulated immune responses and the accumulation of excessive reactive oxygen species （ROS） in Citrus tissues. Here, we report a manganese oxide nanozyme （MONPs） based strategy to scavenge and regulate the ROS metabolism in HLB infected Citrus, thereby protecting leaf tissues against oxidative stress. Transmission electron microscopy （TEM） imaging revealed that MonPs enable efficient delivery into the intercellular space by spraying dispersion. ROS detection indicated the direct ROS scavenging ability of MonPs with high efficiency in HLB-Citrus with about 60% of ROS decreasing. Enzyme activation and gene expression analysis exhibited that the MONP treatment could regulate the ROS metabolism gene in Citrus to alleviate oxidative stress. Current research demonstrated that the HLB-Citrus sprayed with MonPs showed a noticeable protective effect within 22 days to alleviate the blotchy mottle symptoms. Furthermore, various physiological indexes such as MDA, starch, total soluble sugar, carotenoid and chlorophyll in HLB-Citrus leaves exhibited significant improvement post-MONP treatment. This MONP-based approach provides a promising alternative strategy to modulate and mitigate oxidative stress in HLB-Citrus, thereby serving the Citrus industry.
論文鏈接：
https://doi.org/10.1039/D4EN00519H
