Bacterial bacterial leaf blight of rice is one of the three major traditional rice diseases in China. In recent years, with the change of climate and farming system, the disease has re erupted and prevailed in Zhejiang and major rice regions in China, and new epidemic laws have emerged, which has brought great challenges to the prevention and control of the disease. At present, bacterial leaf blight has occurred in all rice regions in Zhejiang Province, As one of the ten chemical emerging technologies that will change the world in the future, nano pesticides are currently being applied to the prevention and control of rice bacterial blight disease in Zhejiang Province. Therefore, it is urgent to understand its field mechanism, so as to provide theoretical guidance for the future use of nano materials in the prevention and control of rice bacterial diseases.
On July 6, 2022, nano today (if5y=20.24), an authoritative journal in the field of nanotechnology, published online the”bioengineered Chinese iron nanocomposite controls bacterial leaf blue disease by modulating plant defense respo” by Professor Li Bin of the school of agriculture of Zhejiang Universitynse and nutritioThe research paper of nal status of rice (Oryza sativa L.)”reveals a new mechanism for the prevention and control of bacterial leaf blight of rice by nano materials by directly destroying pathogenic bacteria and affecting the defense response and nutritional status of plants, and regulating the structure of microbial community in rhizosphere soil, which has important guiding significance for the prevention and control of bacterial diseases of rice.
Professor Li Bin’s research group first reported that chitosan iron nanocomposite (BNC) helps rice resist biological stress such as bacterial blight, based on the previous revelation that nano materials help rice resist abiotic stress (Journal of hazards materials, 2022) and the summary of its application prospects in rice production (critical reviews in food science and nutrition, 2022), The bactericidal activities of BNC in vitro and in vivo were determined, the effects of BNCS on healthy and infected rice endophytic microbiota were evaluated, and the internal mechanism of BNCS reducing the harm of rice bacterial blight was proposed. The results showed that BNCS could inhibit Xanthomonas oryzae Xoo through various mechanisms, such as direct and indirect effects. First, the interaction between BNCS and bacteria caused the controlled release of fe2+ ions, resulting in cell membrane rupture, reactive oxygen species formation, DNA damage, protein and enzyme denaturation, as well as the leakage of cell contents, and finally led to the death of Xoo cells; Secondly, BNC can enter leaves through stomata and disperse in the large space of spongy mesophyll cells. The accumulation of BNC in plants triggers salicylic acid signaling pathway and antioxidant defense mechanism, improves photosynthetic characteristics and nutrient acquisition, maintains ion dynamic balance, and finally removes reactive oxygen species and alleviates cell oxidative stress in rice plants. In addition, high-throughput sequencing results showed that BNCS reduced the relative abundance of Xanthomonas and increased the bacterial community diversity of healthy and diseased plants by reshaping the endophytic bacterial communities on the leaf surface and roots of rice, especially the relative abundance of biological nitrogen fixing microorganisms such as heterorhizobia and slow-growing rhizobia, which may also play an important role in the nano control of rice bacterial blight.
Temoor Ahmed, a doctoral candidate, is the first author, and Professor Jason C. white of the agricultural experimental station of Connecticut, the United States, academician Chen Jianping of Ningbo University and Professor Li Bin of Zhejiang University are the corresponding authors, who jointly guided the development of this study. Professor Ma Chuanxin of Guangdong University of technology and Professor Muhammad Shahid of Pakistan University of Government participated in the research of this project. This research was supported by the State Key Laboratory of”Rice Biology”, the National Natural Science Foundation Project (3187201732072472), the key research and development project of Zhejiang Province (2019c02006) and the key project of the natural science foundation of Zhejiang Province (lz19c140002).