Interactions Between Strawberry ABA Receptor PYR/PYLs and Protein Phosphatase PP2Cs on Basis of Transcriptome and Yeast Two-Hybrid Analyses

Abstract

Strawberry (Fragaria × ananassa) is an ideal model plant for studies on non-climacteric fruit ripening. Although much progress has been made towards understanding the molecular mechanism of strawberry fruit ripening regulated by abscisic acid (ABA), little is known about the interactions between members of the FaPYR/PYL and FaPP2C families. Here, using RNA-seq, qPCR, and yeast two-hybrid analyses, we found that the FaPYR/PYL and FaPP2C gene families both have nine members, respectively, among which FaPYL2/4/8/9/11/12 and FaABI1/FaPP2C16/51/16L2/16L1/37 showed relatively higher expression at the mRNA level during ripening. The transcript abundance of candidate members of the FaPYR/PYLs and FaPP2Cs families tended to increase and decrease, respectively, at the onset of fruit reddening. In phylogenetic analyses, FaPYL2, FaPYL4, FaPYL11/FaPYL12, and FaPYL8/FaPYL9 were classified into four subgroups, and FaABI1/FaPP2C16/FaPP2C16L/FaPP2C6, FaPP2C24/FaPP2C37, and FaPP2C8/FaPP2C51 were classified into three subgroups. In yeast two-hybrid analyses, FaPYL4/9/11 and FaABI1/FaPP2C16 were able to interact with each other. ABA could not promote interactions between un-interacted pairs of FaPYL2/8/12 and FaPP2C16/51/37. FaABI1 and FaPYL2 interaction may play a major role in ripening. This is the first report on the analysis of interactions between members of the FaPYR/PYLs and FaPP2Cs families in strawberry. The results provide insights into ABA signal transduction during non-climacteric fruit ripening.