Abstract
Background: Polygalacturonase (PG) belongs to a large family of hydrolases that undertake many important functions in cell separation during plant growth and development by degrading pectin. The specific expression of PG genes in pollen may have great significance for plant male sterile research and hybrid wheat breeding. However, it has not been reported in wheat ( Triticum aestivum L.).
Results: Therefore, we systematically studied the PG gene family using the latest published wheat reference genomic information. A total of 113 PGs were identified and renamed as TaPG01 - 113 based on their position on the chromosome. They were unequally distributed on 21 chromosomes and were classified into six categories of A-F. Analysis of gene structures and conserved motifs revealed that the TaPGs of Class C and D had relatively short gene sequences and a small number of introns, and Class E TaPGs were the least conserved and all members did not have III conserved domain. Segmental duplication has been shown to be one of the major drivers of the expansion of the wheat PG gene family. The cis-element predictions indicate that wheat PGs had a wide range of functions, including response to light, hypothermia, anaerobic and hormonal stimulation, and also involved in meristematic tissue expression. In addition, twelve spike-specific expressions of TaPGs were screened using RNA-seq data, and finally three important genes were identified by expression analysis in the sterile and fertile anthers of thermo-sensitive male sterile wheat. TaPG93 was involved in the pollen development and elongation of pollen tubes, and TaPG87 and TaPG95 played important roles in the separation of pollen grains and the cracking of anthers dehiscence.
Conclusions: This study, we performed a thorough analysis of the wheat PG gene family and finally obtained three TaPGs that affect wheat fertility. This will lay a solid foundation for the function exploration of wheat PG gene family and provide new enlightenment for the fertility conversion mechanism of male sterile wheat.
Comprehensive analysis of polygalacturonase family highlights candidate genes related to pollen development and male fertility in wheat (Triticum aestivum L.)
