PAV markers in Sorghum bicolour: genome pattern, affected genes and pathways, and genetic linkage map construction

KEY MESSAGE: 5,511 genic small-size PAVs in sorghum were identified and examined, including the pattern and the function enrichment of PAV genes. 325 PAV markers were developed to construct a genetic map. ABSTRACT: Presence/absence variants (PAVs) correlate closely to the phenotypic variation, by impacting plant genome sizes and the adaption to the environment. To shed more light on their genome-wide patterns, functions and the possibility of using them as molecular markers, we generated next generation genome sequencing data for four sorghum inbred lines and used associated bioinformatic pipelines to identify small-size PAVs (40–10 kb). Five thousand five hundreds and eleven genic PAVs (40–10 kb) were identified and found to affect 3,238 genes. These PAVs were mainly distributed on the sub-telomeric regions, but the highest proportions occurred in the vicinity of the centromeric regions. One of the prominent features of the PAVs is the high occurrence of long terminal repeats retrotransposons and DNA transposons. PAVs caused various alterations to gene structure, primarily including the coding sequence variants, intron variants, transcript ablation, and initiator codon changes. The genes affected by PAVs were significantly enriched in those involved in stress responses and protein modification. We used 325 PAVs polymorphic between two sorghum inbred lines Ji2731 and E-Tian, together with 49 SSR markers, and constructed a genetic map, which consisted of 10 linkage groups corresponding to the 10 chromosomes of sorghum and spanned 1,430.3 cM in length covering 97 % of the physical genome. The resources reported here should be useful for genetic study and breeding of sorghum and related species. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00122-015-2458-4) contains supplementary material, which is available to authorized users.