Identification and characterization of long-InDels through whole genome resequencing to facilitate fine-mapping of a QTL for plant height in soybean (Glycine max L. Merr.)

With the development of sequencing technology, insertions-deletions (InDels) have been increasingly reported to be involved in the genetic determination of agronomical traits. However, most studies have focused on the identification and application of short-InDels (1–15 bp) for genetic analysis. The objective of this study was to deeply deploy long-InDels (>15 bp) for the genetic analysis of important agronomic traits in soybean. A total of 13 573 polymorphic long-InDels were identified between parents Zhongpin 03-5373 (ZP) and Zhonghuang 13 (ZH), which were unevenly distributed on 20 chromosomes of soybean, varying from 321 in Chr11 to 1 246 in Chr18. Consistent with the distribution pattern of annotated genes, the average density of long-InDels in arm regions was significantly higher than that in pericentromeric regions at the P=0.01 level. A total of 2 704 (19.9% of total) long-InDels were located in genic regions, including 319 large-effect long-InDels, which resulted in truncated or elongated protein sequences. A previously identified QTL (qPH16) underlying plant height was further analyzed, and it was found that 26 out of 35 (74.3%) long-InDel markers located in the qPH16 region showed clear polymorphisms between parents ZP and ZH. Seven markers, including three long-InDels and four previously reported SNP markers, were used to genotype 242 recombinant inbred lines derived from ZP×ZH. As a result, the qPH16 locus was narrowed from a 960-kb region to a 477.55-kb region, containing 65 annotated genes. Therefore, these long-InDels are a complementary genetic resource of SNPs and short-InDels for plant height and can facilitate genetic studies and molecular assisted selection breeding in soybean.