Tandem repeats (TRs) are genomic regions that tandemly change in repeat number, which are often multiallelic. Their characteristics and contributions to gene expression and quantitative traits in rice are largely unknown. Here, we survey rice TR variations based on 231 genome assemblies and the rice pan-genome graph. We identify 227,391 multiallelic TR loci, including 54,416 TR variations that are absent from the Nipponbare reference genome. Only 1/3 TR variations show strong linkage with nearby bi-allelic variants (SNPs, Indels and PAVs). Using 193 panicle and 202 leaf transcriptomic data, we reveal 485 and 511 TRs act as QTLs independently of other bi-allelic variations to nearby gene expression, respectively. Using plant height and grain width as examples, we identify and validate TRs contributions to rice agronomic trait variations. These findings would enhance our understanding of the functions of multiallelic variants and facilitate rice molecular breeding. Tandem repeats (TRs) have unique ability to drive a range of phenotype variations. Here, the authors survey rice TR variations based on 231 genome assemblies and the rice pan-genome graph, identify TR variations associated with expressed genes, and reveal expression TRs contributed to rice agronomic trait variations.

The pan-tandem repeat map highlights multiallelic variants underlying gene expression and agronomic traits in rice