J Syst Evol ›› 2023, Vol. 61 ›› Issue (2): 345-355.DOI: 10.1111/jse.12852

• Research Articles • Previous Articles     Next Articles

Patterns and impacting factors of gene evolutionary rate between wild and cultivated emmer wheat (Triticum turgidum)

Peng-Zheng Lei1, Qi Ai1, Zhu-Pei Xiong1, Jia‐Nan Lu1, Xiu-Lan Wei1, Weining Song1, Xiao-Qin Liu3*, and Xiao-Jun Nie1,2*   

  1. 1 State Key Laboratory of Crop Stress Biology in Arid Areas, College of Agronomy and Yangling Branch of China Wheat Improvement Center, Northwest A&F University, Yangling 712100, Shaanxi, China
    2 ICARDA-NWSUAF Joint Research Center, Yangling 712100, Shaanxi, China
    3 Peking University Institute of Advanced Agricultural Science, Weifang 261325, Shandong, China
    *Authors for correspondence. Xiao-Qin Liu. E‐mail: xiaoqin.liu@pku-iaas.edu.cn; Xiao-Jun Nie. E‐mail: small@nwsuaf.edu.cn
  • Received:2021-11-03 Accepted:2022-03-21 Online:2022-04-08 Published:2023-03-01

Abstract: Tetraploid emmer wheat (Triticum turgidum L., BBAA) is the founder progenitor of bread wheat, providing the valuable genetic resource and gene pool for wheat improvement. However, the evolutionary trajectory of tetraploid wheat, especially the evolutionary fate of different types of genes has not been well studied. In this study, the rate of non-synonymous substitution (dN) and synonymous substitution (dS) was calculated by comparing the orthologs between the wild emmer and cultivated durum wheat at the whole genome and subgenome levels to obtain the positively selected genes (PSGs) and negatively selected genes (NSGs). Then, mutation rate, gene length, exon number, GC content, codon bias, and expression level were comprehensively investigated and compared between the PSGs and NSGs. Within both wild emmer and cultivated durum wheat, PSGs between A and B subgenome displayed shorter gene and exon lengths as well as fewer exon numbers compared with NSGs, whereas from wild emmer to cultivated durum wheat, PSGs showed longer gene length and more exon numbers. Furthermore, PSGs displayed much higher expression levels and stronger codon usage bias, but lower genetic diversity compared with NSGs. Finally, two PSGs TdER1-6B, and TdLC7-2A, were found to play the crucial roles in regulating grain width and plant height of tetraploid wheat, respectively. This study systematically investigated the evolutionary, structural, and functional difference between PSGs and NSGs in tetraploid wheat, which will contribute to a better understanding of the selective mode and evolutionary trajectory during wheat domestication and evolution.

Key words: domestication, evolution rate, positively selected genes (PSGs), selective mode, tetraploid emmer wheat