[Application of host induced gene silencing in crop protection against fungal diseases].

Fungal diseases are the main threat to crop yield and quality, often leading to huge economic losses. Chemical fungicides are almost useless to soil-borne and vascular fungal pathogens. The most effective way is crop resistance breeding by using resistance genes. Yet, for plants lacking resistance resources, new approaches are urgently needed for crop protection. Recently, host-induced gene silencing (HIGS) is developed based on the well-known RNA interference, and already effective against viruses and pests. However, it is challenging to validate HIGS in soil-borne fungal pathogens due to uncharacterized and complicated infection processes. Recently, we have made great progresses in revealing the infection structure of Verticillium dahliae, a soil-borne and vascular fungal pathogen that leads to verticillium wilt disease to many crops, including cotton plants. Moreover, we demonstrate that cotton exports endogenous microRNAs to inhibit virulence gene expression in V. dahliae. The most exciting achievement is the successful application of HIGS in cotton plants that confer resistance to V. dahliae. All these results reveal a promising potential for applying HIGS against a wide range of soil-borne fungi.真菌病害严重威胁作物的产量和品质，给国家和人民造成巨大的经济损失。尤其是引起维管束病害的土传真菌，化学农药的作用效果很不理想。利用抗性基因进行遗传育种是目前生物防治的重要手段之一，但对于缺乏抗性资源的物种，面对强大的土壤真菌病害，研究者也时常束手无策。近年来，利用RNA 干扰技术发展而来的宿主诱导的基因沉默 (Host induced gene silencing，HIGS) 策略，在抗病虫害领域逐渐崭露头角，但由于真菌侵染的复杂多样性及土壤传播的特性，HIGS 在土壤真菌病害中的应用充满神秘和挑战。本研究室近期揭示了棉花黄萎病 (一种严重的土壤真菌病害) 的“罪魁祸首”——大丽轮枝菌的侵染结构和侵染过程；并首次证明了宿主植物内源小RNA 能够跨界进入病原菌细胞中降解致病基因表达的抗病作用；在此基础上，本研究室利用HIGS 在棉花上获得了对黄萎病抗性较高的品系，成功地开辟了抗土壤黄萎真菌病害的新天地，研究结果显示出基因沉默技术在这一领域强大的应用潜力和前景。.