New Insights Into Invertase Gene Family and Functional Characterization of Critical Cell Wall Invertase TaCWINV40 For Male Fertility in Wheat (Triticum Aestivum L.)

Abstract Invertase (INV, ec3.2.1.26) irreversibly hydrolyzes sucrose into fructose and glucose, and it is regulated by the environment to affect pollen fertility in some plant species. However, there has been a lack of systematic identification of INV gene family in wheat. In order to reveal the potential influence on the male fertility, a total of 130 wheat INVs that unevenly distributed on 21 chromosomes were systematically identified and analyzed in this study. According to physical and chemical properties, subcellular location, and phylogenetic tree, they were divided into two acidic INV (AINV) subtypes: cell wall group (TaCWINV1-68), vacuole group (TaVINV1-42), and two neutral/alkaline INV (A/NINV) subtypes: cytoplasmic α group (TaA/NINV1-11) and cytoplasmic β group (TaA/NINV12-20). The amplification of A/NINVs is mainly attributed to the polyploidization of wheat, and the multiple duplication events experienced in AINVs revealed their non-dose sensitivity characteristic. The wheat RNA-seq data revealed the tissue specificity of A/NINVs and AINVs, and six spike-specific CWINVs showed significant differential expression between the fertile and sterile anthers of thermo-sensitive male-sterile wheat KTM3315A. TaCWINV40 localized in cell wall was effectively silenced in the fertile KTM3315A, and the malformed pollen grains and non-germinating pollen tubes shed light on its indispensability in the development of wheat anthers. This study will spur the interest on manipulating the novel genetic characteristics of TaCWINVs for the construction and improvement of wheat male sterile materials.