Intra-Varietal Diversity and Its Contribution to Wheat Evolution, Domestication, and Improvement in Wheat

Abstract

Crop genetic diversity is essential for adaptation and productivity in agriculture. A previous study revealed that poor allele diversity in wheat commercial cultivars is a major barrier to its further improvement. Homologs within a variety, including paralogs and orthologs in polyploid, account for a large part of the total genes of a species. Homolog diversity, intra-varietal diversity (IVD), and their functions have not been elucidated. Common wheat, an important food crop, is a hexaploid species with three subgenomes. This study analyzed the sequence, expression, and functional diversity of homologous genes in common wheat based on high-quality reference genomes of two representative varieties, a modern commercial variety Aikang 58 (AK58) and a landrace Chinese Spring (CS). A total of 85,908 homologous genes, accounting for 71.9% of all wheat genes, including inparalogs (IPs), outparalogs (OPs), and single-copy orthologs (SORs), were identified, suggesting that homologs are an important part of the wheat genome. The levels of sequence, expression, and functional variation in OPs and SORs were higher than that of IPs, which indicates that polyploids have more homologous diversity than diploids. Expansion genes, a specific type of OPs, made a great contribution to crop evolution and adaptation and endowed crop with special characteristics. Almost all agronomically important genes were from OPs and SORs, demonstrating their essential functions for polyploid evolution, domestication, and improvement. Our results suggest that IVD analysis is a novel approach for evaluating intra-genomic variations, and exploitation of IVD might be a new road for plant breeding, especially for polyploid crops, such as wheat.

An Evaluation of the Crop Preference and Phenotypic Characteristics of Ceracris kiangsu Tsai (Orthoptera: Arcypteridae) under Different Temperatures

“…For this study, we chose four different Chinese staple crops, including common wheat (Aikang 58, Henan Bainong Seed Industry Co., Ltd., Xinxiang, China), rice (Xiangzaoxian 45, Hunan Dongting Gaoke Seed Industry Co., Ltd., Yueyang, China), waxy maize (Jinghuangnuo, Beijing Huaao Nongke Jade Breeding Development Co., Ltd., Beijing, China), and sweet maize (Suketian 1506, Nanjing Jiahua Agricultural Development Co., Ltd., Nanjing, China), which were disease-resistant or widely cultivated in China [23][24][25][26]. The soaked seeds were planted with wet nutrient soil in the plastic pots (20 cm height × 20 cm diameter), covered with preservative film to preserve their humidity, and watered appropriately.…”