Distribution and conservation of simple sequence repeats in plant pathogenic species of Zymoseptoria and development of genomic resources for its orphaned species.

ABSTRACT

To better understand the structure and evolution of the genomes of four plant pathogenic species of Zymoseptoria, we analyzed the occurrence, relative abundance (RA), and density (RD) of simple sequence repeats (SSRs) in their whole genome and transcriptome sequences. In this study, SSRs are defined as repeats of more than 12 bases in length. The genome and transcriptome sequences of Zymoseptoria ardabiliae show the highest RA (201.1 and 129.9) and RD (3229.4 and 1928.2) of SSRs, while those of Zymoseptoria pseudotritici show the lowest RA (167.2 and 118.5) and RD (2482.2 and 1687.0). The majority of SSRs in the genomic and transcriptome sequences of species were trinucleotide SSRs, while dinucleotide SSRs were the least common. The most common trinucleotide motifs in the transcriptomic sequences across all species were those that encoded the amino acid arginine. As per our motif conservation study, Zymoseptoria tritici (12.4%) possessed the most unique motifs, while Z. pseudotritici (3.9%) had the fewest. Overall, only 38.1% of the motifs were found to be conserved among the species. Gene enrichment studies reveal that three of the species, Z. ardabiliae, Zymoseptoria brevis, and Z. pseudotritici, have SSRs in their genes related to cellular metabolism, while the remaining Z. tritici harbors SSRs in genes related to DNA synthesis and gene expression. In an effort to improve the genetic resources for the orphan species of pathogenic Zymoseptoria, a total of 73,134 primers were created. The genomic resources developed in this study could help with analyses of genetic relatedness within the population and the development of species-specific markers.