In-Depth Sequence Analysis of Bread Wheat VRN1 Genes

Area of Science:

• Plant genetics
• Molecular biology
• Agricultural science

Background:

• The VERNALIZATION1 (VRN1) gene is crucial for wheat's transition from vegetative to reproductive growth in response to cold.
• Allelic variations in VRN1 homoeologs significantly affect wheat flowering time.

Purpose of the Study:

• To explore the genetic variability of VRN1 homoeologs (VRN-A1, VRN-B1, VRN-D1) in wheat.
• To identify novel alleles and understand their impact on heading time.

Main Methods:

• In-depth sequence analysis of VRN1 homoeologs in 105 winter and spring wheat varieties.
• Copy number variation (CNV) analysis of VRN1 homoeologs.
• Expression pattern analysis of identified alleles.

Main Results:

• A novel allele, Vrn-B1f, with an intron 1 insertion, was identified, showing specific expression linked to earlier heading.
• The Vrn-A1b allele exhibits an alternative splice variant due to an intron 1 insertion.
• Copy number of VRN-A1 varied (1-4 for recessive, 1-2 for dominant), while VRN-B1 and VRN-D1 were single copy.
• Deletion of G-quadruplex structures in promoter regions was observed in cultivars with higher vrn-A1 copy numbers.

Conclusions:

• Genetic variability in VRN1 homoeologs, including novel alleles and copy number variations, contributes to diverse flowering times in wheat.
• The identified VRN1 variations offer potential targets for breeding programs to optimize wheat heading time.