Walnut phosphatase 2A proteins interact with basic leucine zipper protein JrVIP1 to regulate osmotic stress response calcium signaling.

Walnut is an important economic tree species that is susceptible to osmotic stress. Scientific cultivation management is an important way to improve the yield and quality of walnuts, which requires understanding the regulatory mechanisms in response to osmotic stress. Therefore, in this study, 15 protein phosphatase 2A () genes were identified from the walnut transcriptome (named ~) and their potential function responses to osmotic stress were elucidated. The open reading frame (ORF) of ranges from 651 to 1,764 bp in length, the molecular weight of the encoded proteins are 24.15-65.61 kDa, and the theoretical isoelectric points are 4.80-8.37. These were unevenly distributed on 10 chromosomes and divided into five groups based on the composition of conserved domains, motifs, and exon/intron organizations. The five groups are , , , and , including 1, 5, 2, 3, and 4 members, accordingly. The -elements in ' promoters were involved in responses to hormone and abiotic stress. Most genes, excluding , , , , and , could be induced significantly by PEG, NaCl, CaCl and ABA. JrPP2A02, JrPP2A05, JrPP2A07, JrPP2A09, and JrPP2A14, could independently interact with a bZIP transcription factor JrVIP1. Moreover, overexpression of , and could significantly decrease ROS accumulation while increasing calcium (Ca) uptake exposed to PEG and NaCl stresses, which was mediated by exogenous CaCl and ABA. These results suggested that genes play potential key roles in walnut response to drought and salt-inducing osmotic stress involving Ca- and ABA-dependent signaling pathways.