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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #388995

Research Project: Genetic Improvement and Cropping Systems of Warm-season Grasses for Forage, Feedstocks, Syrup, and Turf

Location: Crop Genetics and Breeding Research

Title: Whole genome sequencing of Clarireedia aff. paspali reveals potential pathogenesis factors and genome plasticity in Clarireedia species, causal agents of dollar spot in turfgrass

item BAHRI, B - University Of Georgia
item PARVATHANENI, R - University Of Georgia
item SPRATLING, T - University Of Georgia
item Sapkota, Suraj
item RAYMER, P - University Of Georgia
item MARTINEZ-ESPINOZA, A - University Of Georgia

Submitted to: Frontiers in Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: Turfgrass is a valuable commodity worldwide and in the US. Dollar spot, caused by Clarireedia spp, is the most common and damaging disease in turfgrass. In this study, the draft genome of two Clarireedia spp., isolates, H2 and H3, were sequenced. Both isolates were identified as C. aff. paspali, a novel species in the US. This is also the first report of C. aff. paspali in the US. Additionally, several genes potentially involved in Clarireedia development and pathogenesis were highlighted from this genomic analysis. Because of the limited genomic resources published for members of the Rutstroemiaceae family and for Clarireedia species more specifically, our study provides valuable genomic information for future research discoveries on plant pathogens.

Technical Abstract: Dollar spot is one of the most damaging diseases in turfgrass, reducing its quality and playability. Two species, C. monteithiana and Clarireedia jacksonii (formerly Sclerotinia homoeocarpa) have been reported so far in the US. To study the Clarireedia genome, two isolates H2 and H3, sampled from seashore paspalum in Hawaii in 2019 were sequenced via Illumina paired-end sequencing by synthesis technology and PacBio SMRT sequencing. Both isolates were identified as C. aff. paspali, a novel species in the US. Using short and long reads, C. aff. paspali H3 contained 193 contigs with 48.6 Mbp and presented the most completed assembly and annotation among Clarireedia species. To decipher Clarireedia pathogenicity, C. aff. paspali genomes (H2 and H3), as well as available C. jacksonii (LWC-10 and HRI11), C. monteithiana (DRR09 and RB-19) genomes were screened for 57 pathogenesis determinants, previously identified in S. sclerotiorum. Seventeen orthologs of pathogenicity genes have been identified in Clarireedia species involved in oxalic acid production (pac1 and nox1), mitogen-activated protein kinase cascade (pka1, smk3, ste12), appressorium formation (caf1, pks13, ams2, rgb1, rhs1) and glycolytic pathway (gpd). Within these genes, 366 species-specific SNPs were recorded between Clarireedia species; 28 were non-synonymous and non-conservative. Although a high level of synteny was observed, at least nineteen translocations were identified between C. aff. paspali (H3) and C. jacksonii (HRI11), suggesting genetic differentiation and genome plasticity between Clarireedia species. These genome and genetic variations could potentially lead to variation in pathogenesis and other physiological functions among Clarireedia species.