Genetic map‐guided genome assembly reveals a virulence‐governing minichromosome in the lentil anthracnose pathogen Colletotrichum lentis

Summary

• Colletotrichum lentis causes anthracnose, which is a serious disease on lentil and can account for up to 70% crop loss. Two pathogenic races, 0 and 1, have been described in the C. lentis population from lentil.

• To unravel the genetic control of virulence, an isolate of the virulent race 0 was sequenced at 1481‐fold genomic coverage. The 56.10‐Mb genome assembly consists of 50 scaffolds with N ₅₀ scaffold length of 4.89 Mb. A total of 11 436 protein‐coding gene models was predicted in the genome with 237 coding candidate effectors, 43 secondary metabolite biosynthetic enzymes and 229 carbohydrate‐active enzymes ( CAZymes), suggesting a contraction of the virulence gene repertoire in C. lentis.

• Scaffolds were assigned to 10 core and two minichromosomes using a population (race 0 × race 1, n =  94 progeny isolates) sequencing‐based, high‐density (14 312 single nucleotide polymorphisms) genetic map. Composite interval mapping revealed a single quantitative trait locus ( QTL), qClVIR‐11 , located on minichromosome 11, explaining 85% of the variability in virulence of the C. lentis population. The QTL covers a physical distance of 0.84 Mb with 98 genes, including seven candidate effector and two secondary metabolite genes.

• Taken together, the study provides genetic and physical evidence for the existence of a minichromosome controlling the C. lentis virulence on lentil.