Functional validation of pathogenicity genes in rice sheath blight pathogen Rhizoctonia solani by a novel host‐induced gene silencing system

Abstract

Rice (Oryza sativa) is one of the most important cereal crops cultivated around the world. Rice cultivation often suffers from several types of diseases, including rice sheath blight (RSB), caused by the basidiomycete fungus Rhizoctonia solani. RSB is one of the most devastating rice fungal diseases globally and causes significant yield losses and reductions in rice grain quality (Moni et al., 2016;Rao et al., 2019;Wang et al., 2018). RSB often occurs under warm and humid conditions, particularly in tropical areas. In China, RSB affects over 17 million hectares per year and results in a yield reduction as high as 50% in severely affected areas (https://www.natesc.org.cn).

Host induced gene silencing of Magnaporthe oryzae by targeting pathogenicity and development genes to control rice blast disease

“…In total, five fragments were prepared for HIGS vector construction ( Table 1 ). Using the “Gateway cloning system,” all were first cloned into the entry vector pDONR221 and then moved into the HIGS destination vector individually ( Zhao et al, 2021 ). After recombination cloning, each target fragment was inserted into two regions of the destination vector flanked by recombination sites.…”

“…For HIGS expression, pBDL03 (gift from Dr. Shaohong Qu) was used as the destination vector ( Zhao et al, 2021 ). This vector is derived from the pANDA vector ( Okano et al, 2008 ) and designed so that each target fragment is inserted into two regions flanked by recombination sites in opposite directions, resulting in inverted repeat sequences linked by Gus gene (Fragments were separated by Gus linker, Gus linker sequence can be found on website 4 ), controlled by maize ( Zea mays ) ubiquitin promoter and T3A terminator ( Miki and Shimamoto, 2004 ; Okano et al, 2008 ).…”

“…This vector is derived from the pANDA vector ( Okano et al, 2008 ) and designed so that each target fragment is inserted into two regions flanked by recombination sites in opposite directions, resulting in inverted repeat sequences linked by Gus gene (Fragments were separated by Gus linker, Gus linker sequence can be found on website 4 ), controlled by maize ( Zea mays ) ubiquitin promoter and T3A terminator ( Miki and Shimamoto, 2004 ; Okano et al, 2008 ). The vector contains the hygromycin resistance gene under control of “Cauliflower Mosaic Virus (CaMV) 35S promoter” and 35S terminator for selection in rice ( Zhao et al, 2021 ). In addition, the vector contains mCherry gene ( Subach et al, 2009 ) to facilitate visual confirmation of transgenic plants ( Zhao et al, 2021 ).…”

“…The vector contains the hygromycin resistance gene under control of “Cauliflower Mosaic Virus (CaMV) 35S promoter” and 35S terminator for selection in rice ( Zhao et al, 2021 ). In addition, the vector contains mCherry gene ( Subach et al, 2009 ) to facilitate visual confirmation of transgenic plants ( Zhao et al, 2021 ). This gene was under control of a CaMV 35S promoter and ‘‘ Agrobacterium Nopaline Synthase terminator’’ (tNOS).…”

SsUbc2, a determinant of pathogenicity, functions as a key coordinator controlling global transcriptomic reprogramming during mating in sugarcane smut fungus

“…Given the conserved SAM and RA domains in both ascomycetes and basidiomycetes, a broad spectrum of resistance against many plant fungal diseases caused by ascomycetous pathogens (e.g., rice blast pathogen Magnaporthe oryzea , cotton blight pathogen Verticillium dahlia , and sugarcane Pokkah boeng pathogen Fusarium species complex) and basidiomycetes pathogens (e.g., maize smut pathogen U. maydis , rice sheath blight pathogen Rhizoctonia solani , and sugarcane smut pathogen S. scitamineum ) could be developed by using host-induced gene silencing (HIGS) to target Ubc2 transcripts ( Hua et al, 2018 ; Koch and Wassenegger, 2021 ). In this regard, a current report showed that HIGS was highly efficient for developing transgenic lines in rice resistant to sheath blight caused by R. solani ( Zhao et al, 2021 ). In fact, recombinant microRNAs expressed by cotton plant could inhibit virulent gene expression in V. dahlia , and the transgenic plants showed elevated resistance to cotton blight ( Zhang et al, 2016 ).…”