Genome-wide analysis of invertase gene family in wheat (Triticum aestivum L.) indicates involvement of TaCWINVs in pollen development

Invertase (INV, EC3.2.1.26) is involved in carbohydrate partitioning by irreversibly hydrolyzing sucrose into fructose and glucose. INV genes that are specifically expressed in anthers are closely related to male fertility but they have not been identified in wheat. In this study, we identified 130 INV genes in wheat with uneven distributions on 21 chromosomes. According to their physical and chemical properties, subcellular locations, and phylogenetic analysis, the INV genes were divided into two acidic INV subtypes and two neutral/alkaline INV subtypes. Polyploidy and segmental duplications were found to be mainly responsible for expansion of the wheat INV gene family. Expression profiles in wheat showed that the INV genes had specific temporal and spatial characteristics. Subsequently, TaCWINV40 encoding a cell wall invertase (CWINV) was subjected to further study. Subcellular localization analysis showed that TaCWINV40 was localized in the cell wall. Further phenotypic and cytological analyses of BSMV:TaCWINV40 silenced wheat plants indicated that TaCWINV40 and/or its highly similar duplicates are involved in anther and pollen development. These findings are useful for improving our understanding of INV family members in wheat and they suggest important roles for TaCWINVs in male sterile wheat lines.