PbARP1 enhances salt tolerance of ‘Duli’ pear (Pyrus betulifolia Bunge) through abscisic acid signalling pathway

Pears are a widely cultivated fruit crop; however, the distribution and sustainable production are limited by salt stress. In this study, we identified 35 salt-tolerant genes by means of constructing a yeast expression library. Among the 35 genes, the transcription level of PbARP1 in ‘Duli’ pear (Pyrus betulaefolia Bunge) plants is upregulated under saline stress conditions. Next, we conducted a functional analysis of the PbARP1, the over-expression of PbARP1 in the transgenic pear calli lines exhibited improved tolerance to salt stresses. Conversely, the suppression of PbARP1 resulted in enhanced sensitivity to salt stress. The transcription levels of PbPYL4, PbPYL9, PbPYL8, PbSRK2I, and PbABI5 in PbARP1 silenced pear calli and pear plants presented significant changes, which indicated these genes may be involved in the salt stress response mechanism and regulated by the PbARP1 gene. Besides, we identified an interacting protein of PbARP1: the ABA receptor PbPYL8, highlighting the critical role of PbARP1 and the ABA signalling pathway in regulating pear response to salt stress.