The genetic diversity of 33 Paris polyphylla samples collected from the Dabie Mountains was analyzed using SCoT and SRAP molecular markers, revealing the genetic relationships among Paris polyphylla resources in the Dabie Mountains at the molecular level and providing a theoretical basis for genetic improvement and conservation. As a result, a total of 134 bands were amplified with 9 SCoT primers, the percentage of polymorphic bands was 100%, the average number of primers amplified was 14.89, the PIC value was 94.83% and the genetic similarity coefficient ranged from 0.463 to 0.896. Ten pairs of SRAP primer combinations amplified 135 bands, including 129 polymorphic bands, and the percentage of polymorphic bands was 95.56%. The average number of polymorphic bands obtained with each pair of SRAP primer combinations was 12.9, the PIC value was 93.91%, and the genetic similarity coefficient ranged from 0.533 to 0.904. This study showed that both SCoT and SRAP markers were suitable for the genetic diversity analysis of P. polyphylla, which belongs to a genus in which SRAP marker technology has not previously been applied, despite its application in a variety of other plants.

The SAUR (small auxin-up RNA) gene family is the biggest family of early auxin response genes in higher plants and has been associated with the control of a variety of biological processes. Although SAUR genes had been identified in several genomes, no systematic analysis of the SAUR gene family has been reported in Chinese white pear. In this study, comparative and systematic genomic analysis has been performed in the SAUR gene family and identified a total of 116 genes from the Chinese white pear. A phylogeny analysis revealed that the SAUR family could be classified into four groups. Further analysis of gene structure (introns/exons) and conserved motifs showed that they are diverse functions and SAUR-specific domains. The most frequent mechanisms are whole-genome duplication (WGD) and dispersed duplication (DSD), both of which may be important in the growth of the SAUR gene family in Chinese white pear. Moreover, cis-acting elements of the PbrSAUR genes were found in promoter regions associated with the auxin-responsive elements that existed in most of the upstream sequences. Remarkably, the qRT-PCR and transcriptomic data indicated that PbrSAUR13 and PbrSAUR52 were significantly expressed in fruit ripening. Subsequently, subcellular localization experiments revealed that PbrSAUR13 and PbrSAUR52 were localized in the nucleus. Moreover, PbrSAUR13 and PbrSAUR52 were screened for functional verification, and Dangshan pear and frandi strawberry were transiently transformed. Finally, the effects of these two genes on stone cells and lignin were analyzed by phloroglucinol staining, Fourier infrared spectroscopy, and qRT-PCR. It was found that PbrSAUR13 promoted the synthesis and accumulation of stone cells and lignin, PbrSAUR52 inhibited the synthesis and accumulation of stone cells and lignin. In conclusion, these results indicate that PbrSAUR13 and PbrSAUR52 are predominantly responsible for lignin inhibit synthesis, which provides a basic mechanism for further study of PbrSAUR gene functions.