A yield-associated gene TaCWI, in wheat: its function, selection and evolution in global breeding revealed by haplotype analysis

Abstract

Wheat anther-specific invertase genes were haplotyped in wheat. Strong allelic selection occurred during wheat polyploidization, domestication and breeding because of their association with yield traits. Plant invertase hydrolyzes sucrose into glucose and fructose. Cell wall invertase (CWI), one of the three types of invertase, is essential for plant development. Based on isolated TaCWI genes from chromosomes 4A, 5B and 5D, two SNPs were detected in the promoter region of TaCWI-4A, and four SNPs and two Indels were present in the TaCWI-5D gene. No polymorphism was detected in TaCWI-5B coding or promoter regions. CAPS markers caps4A and caps5D were developed to discriminate haplotypes of TaCWI-4A and TaCWI-5D. Marker/trait association analysis indicated that Hap-5D-C at TaCWI-5D was significantly associated with higher thousand kernel weight (TKW) in 348 Chinese modern cultivars grown in multiple environments. Geographic distributions and changes over time of favored haplotypes showed that Hap-5D-C was the most frequent haplotype in modern cultivars and was strongly positively selected in six major wheat production regions worldwide. However, selection for haplotypes at TaCWI-4A was not so evident, possibly due to balancing effects of the two haplotypes on TKW and grain number per spike (GN). In rainfed production regions, Hap-4A-C was favored because it brought more seeds, but in well irrigated conditions, Hap-4A-T was favored in modern breeding because of higher TKW. Evolutionary analysis among wheat and its relatives showed that genetic diversity of TaCWI genes on chromosomes 4A and 5D declined dramatically in progression from the diploid level to modern polyploid cultivars. There was strong allelic selection during polyploidization, domestication and breeding.

TaGW2, a Good Reflection of Wheat Polyploidization and Evolution

“…In addition, the haplotype numbers of TaGW2-6A and TaGW2-6B decreased from diploids, to tetraploids and hexaploids (Figure 6 and Figure S5). Dramatic reductions in diversity in other genes, such as TaSUS1-7A, TaGS5-5A , and TaCWI , following polyploidization reported in other species (Hou et al, 2014; Jiang et al, 2015; Ma et al, 2016). All of these reports indicate that strong differentiation of important yield-related genes occurred during polyploidization and domestication of both tetraploid and hexaploid wheats.…”

“…Examples include OsGS5, ZmGS3, ZmGW2-CHR4, TaTEF-7A , and TaCWI-4A (Li et al, 2010a,b, 2011; Zheng et al, 2014; Jiang et al, 2015). Previous studies (Su et al, 2011; Qin et al, 2014) also showed that genetic diversity mainly occurred in the promoter regions of TaGW2-6A and TaGW2-6B in common wheat.…”

Major genes determining yield-related traits in wheat and barley

“…Another yield-related wheat anther-specific invertase gene, TaCWI , encodes cell wall invertase (CWI), which hydrolyzes sucrose into glucose and fructose. Among several haplotypes tested, only one, TaCWI - 5D , was significantly associated with TKW (Jiang et al 2015). …”

Cloning and Characterization of TaTGW-7A Gene Associated with Grain Weight in Wheat via SLAF-seq-BSA

“…TaGW2 , encoding an E3 ubiquitin ligase and associated with GW and TGW, was cloned based on the homologous rice gene GW2 (Su et al, 2011). Similarly, TaCwi-A1 associated with TGW (Ma et al, 2012; Jiang et al, 2015), TaGASR7-A1 for GL and yield (Dong et al, 2014), TaGS-D1 for GL and TGW (Zhang et al, 2014), and TaTGW6 encoding an indole-3-acetic acid (IAA)-glucose hydrolase (Hu et al, 2016) have been cloned based on rice gene sequences.…”