CULTIVAR DEVELOPMENT: ACCELERATED INTROGRESSION OF SYNTHETIC HEXAPLOID DERIVED DIVERSITY INTO AN APPLIED HARD WINTER WHEAT BREEDING PROGRAM

Soybean improvement is hindered by a low level of genetic diversity, primarily due to the domestication bottleneck. To facilitate the utilization of the untapped genetic variation in wild soybean for cultivar enhancement, it is essential to understand the genetic and molecular bases underlying domestication-related traits (DRTs). Lately, we have fine-mapped a cluster of QTLs controlling multiple morphological DRTs to a ~29-kb genomic region, which harbors only two duplicated long non-coding RNA (LncRNA) genes. These duplicates each possess two tiny exons that are predicted to encode a small peptide (LncsPT), and two long inverted repeats that enable the production of 21-nt and 22-nt overlapping small RNAs (LncsiRNAs) - abundant in wild soybean, but absent or nearly absent in cultivated soybean. The central goal of this project is to decipher the molecular mechanisms by which the LncRNA genes regulate the DRTs. Specific objectives include 1) functional characterization of the LncRNA genes and identification of causal mutations underlying the DRTs; 2) identification and functional characterization of the key LncsiRNAs and their target genes underlaying the DRTs; 3) validation and functional characterization of the putative LncsPTs; and 4) exploration of soybean re-domestication for the targeted morphological DRTs through genome editing as a pilot experiment.