Genome-Wide Analysis, Expression Profile, and Characterization of the Acid Invertase Gene Family in Pepper

• Main Authors: Long-Bin Shen, Yu-Ling Qin, Zhi-Qiang Qi, Yu Niu, Zi-Ji Liu, Wei-Xia Liu, Huang He, Zhen-Mu Cao, Yan Yang
• Format: Article
• Language: English
• Published: MDPI AG 2018-12-01
• Series: International Journal of Molecular Sciences
• Subjects: acid invertase; pepper; gene expression; enzymatic activity
• Online Access: https://www.mdpi.com/1422-0067/20/1/15

Catalytic decomposition of sucrose by acid invertases (AINVs) under acidic conditions plays an important role in the development of sink organs in plants. To reveal the function of AINVs in the development of pepper fruits, nine <i>AINV</i> genes of pepper were identified. Protein sequencing and phylogenetic analysis revealed that the CaAINV family may be divided into cell wall invertases (CaCWINV1&#8315;7) and vacuolar invertases (CaVINV1&#8315;2). CaAINVs contain conserved regions and protein structures typical of the AINVs in other plants. Gene expression profiling indicated that <i>CaCWINV2</i> and <i>CaVINV1</i> were highly expressed in reproductive organs but differed in expression pattern. <i>CaCWINV2</i> was mainly expressed in buds and flowers, while <i>CaVINV1</i> was expressed in developmental stages, such as the post-breaker stage. Furthermore, invertase activity of CaCWINV2 and CaVINV1 was identified via functional complementation in an invertase-deficient yeast. Optimum pH for CaCWINV2 and CaVINV1 was found to be 4.0 and 4.5, respectively. Gene expression and enzymatic activity of CaCWINV2 and CaVINV1 indicate that these AINV enzymes may be pivotal for sucrose hydrolysis in the reproductive organs of pepper.