Development of Intragenic InDel Markers From RNA-Seq Data for Map-Based Cloning and Marker-Assisted Selection in Maize (Zea mays L.)

Maize is one of the most extensively grown and produced crops in the world. Functional molecular markers (FMM) are essential tools for enhancing the efficiency of both breeding and basic research. The transcriptome obtained from high-throughput sequencing is a valuable resource for developing FMM. In this study, we precisely identified high-density and highly polymorphic RNA-derived InDel markers from 368 high-quality, high read depth maize RNA-seq datasets using stringent criteria. The nonredundant marker dataset comprised 13,904 InDel markers with a Polymorphism Information Content (PIC) >= 0.5 and a principal allelic difference (length difference between the most and second most frequent alleles) >= 3 bp, covering 7749 genes. Subsequently, the polymorphism of InDel markers was verified experimentally. Fifty InDel markers were randomly selected, and their average PIC values in 20 maize inbred lines selected from 368 RNA-seq samples and 20 newly selected maize inbred lines were 0.53 and 0.54, with range intervals of 0.18 to 0.77 and 0.22 to 0.74, respectively. The high density and polymorphism of RNA-derived InDel markers identified in this study make them effective tools for maize gene cloning, genetic diversity studies, genome-wide association analysis, and marker-assisted selection.