Abstract:

Extreme low temperatures in winter can cause freezing injury to Korla fragrant pear trees，leading to severe secondary diseases. As a major regulatory signal during overwintering，abscisic acid（ABA）ensures safe overwintering by regulating tree dormancy and cellular physiology. To investigate the role of ABA signaling in the overwintering process of Korla fragrant pear，this study focused on PsPP2C，a key gene in the ABA signaling pathway，and identified and analyzed the response of the PsPP2C gene family to cold stress，aiming to clarify the function of this gene during overwintering. The PsPP2C gene family was subjected to genome-wide identification via bioinformatics methods，and their physicochemical properties，conserved protein domains，etc.，were analyzed. Meanwhile，the relationships between ABA content and water content as well as soluble protein content in the phloem of Korla fragrant pear during overwintering were measured to assess the role of ABA. The result showed that the genome of Korla fragrant pear contains 105 members of the PsPP2C gene family. By comparing with the PP2C genes in Arabidopsis thaliana that interact with the SnRK2 gene，a total of 10 PsPP2C genes were found to potentially participate in ABA signaling regulation during overwintering. These 10 genes are unevenly distributed on 8 chromosomes and are all upregulated during overwintering. It is speculated that these 10 PsPP2C genes may play major roles in overwintering，thereby enhancing the cold stress tolerance of Korla fragrant pear.

Key words: Korla fragrant pear, PsPP2C gene family, bioinformatics, expression analysis, ABA signaling pathway, cold stress