Identification and Expression Analysis of Abscisic Acid Signal Transduction Genes in Hemp Seeds

Abscisic acid (ABA) is involved in regulating diverse biological processes, but its signal transduction genes and roles in hemp seed germination are not well known. Here, the ABA signaling pathway members, PYL, PP2C and SnRK2 gene families, were identified from the hemp reference genome, including 7 CsPYL (pyrab-actin resistance1-like, ABA receptor), 8 CsPP2CA (group A protein phosphatase 2c), and 7 CsSnRK2 (sucrose nonfermenting1-related protein kinase 2). The content of ABA in hemp seeds in germination stage is lower than that in non-germination stage. Exogenous ABA (1 or 10 μM) treatment had a significant regulatory effect on the selected PYL, PP2C, SnRK2 gene families. CsAHG3 and CsHAI1 were most significantly affected by exogenous ABA treatment. Yeast two-hybrid experiments were performed to reveal that CsPYL5, CsSnRK2.2, and CsSnRK2.3 could interact with CsPP2CA7 and demonstrate that this interaction was ABA-independent. Our results indicated that CsPYL5, CsSnRK2.2, CsSnRK2.3 and CsPP2CA7 might involve in the ABA signaling transduction pathway of hemp seeds during the hemp seed germination stages. This study suggested that novel genetic views can be brought into investigation of ABA signaling pathway in hemp seeds and lay the foundation for further exploration of the mechanism of hemp seed germination.