A High-Quality Genome of Rhizoctonia solani, a Devastating Fungal Pathogen with a Wide Host Range

Genome Announcement Rice sheath blight caused by the filamentous fungus Rhizoctonia solani is a serious disease worldwide that leads to yield losses up to 45% and seriously threatens global food security (Nadarajah et al. 2017; Zhang et al. 2021). One of the distinct characteristics of R. solani is that it shows a wide host range and causes diseases on more than 200 plant species, including rice, maize, potato, pepper, cotton, and many ornamental plants (Sneh et al. 1998; Zhang et al. 2021). The infection process of R. solani initiates when scle-rotia or mycelia attach to the host. Subsequently, specialized T-shaped structures called infection cushions form on the plant surface. Infection cushions secrete digestive en-zymes that disrupt the plant cell walls, enabling colonization of the host tissue. Gradually, fungal hyphae invade and kill the plant cells, and the infected plant withers when seriously damaged (Abdoulaye et al. 2019). At the end of the disease cycle, R. solani produces sclerotia, which can survive in soil for many years (Long et al. 2019; Zhang et al. 2021). Owing to its wide host range, soil-borne, and saprotrophic nature, management measures to control R. solani including breeding strategies, crop rotation, and fungicides are ineffec-tive (Abdoulaye et al. 2019), and diseases caused by R. solani have become increasingly serious all over the world (Li et al. 2021). Furthermore, the population genomics struc-ture of R. solani strains is complex, consisting of 14 genetic groups, called anastomosis groups (AGs), named AG-1 to AG-13 and AG-BI (Zhang et al. 2021). There is also lim-ited knowledge about the genetic structure within populations and the reproductive mode (Zheng et al. 2013). Here, therefore, we sequenced and assembled a high-quality genome of R. solani AG-1 IA strain HG81, using both Nanopore long reads and next-generation sequencing (NGS) short reads.

Automated summary

Rice sheath blight caused by the filamentous fungus Rhizoctonia solani is a serious disease worldwide, with a wide host range and complex genetic structure among strains. Efforts to control this disease using management measures have proven ineffective, leading to increasing severity of diseases caused by this fungus globally.