Ascochyta blight of lentil is a devastating fungal disease caused by the hemibiotrophic fungal pathogen Ascochyta lentis. This disease leads to significant yield loss and reduced seed quality when not managed properly. Fungal pathogens employ a suite of effectors to manipulate their host. Here, we present telomere-to-telomere assemblies, genome annotations, and comparative genome analysis of two A. lentis isolates, AlKewell and P94-24, with opposing virulence profiles to identify and characterise effector-like elements. The two genomes are highly syntenic and only contain a small number of structural variations, mostly limited to repeat-rich regions, more specifically long terminal repeat retrotransposons. Protein coding genes were ranked for their effector likelihood using Predector. The top 12 candidate effectors were characterised by agroinfiltration into Nicotiana benthamiana, of which 11 candidates induced necrotic lesions including the two candidates present only in AlKewell. Another major difference is the presence of Penelope-like elements of type Coprina at several chromosomal ends in the genome of P94-24 and their absence in AlKewell. AlKewell on the other hand contains two biosynthetic gene clusters which are heavily truncated in P94-24 and are predicted to encode genes involved in the synthesis of known fungal toxins, one of which is an effector candidate that induced necrosis on N. benthamiana. These genomic resources present new interesting effector candidates and other putative pathogenicity elements that should advance our understanding of the complex lentil-pathogen interaction.
Debler et al. (Mon,) studied this question.