초록
<P><B>Background</B></P><P>Polygalacturonase (PG), a crucial enzyme involved in pectin degradation, is associated with various plants’ developmental and physiological processes such as seed germination, fruit ripening, fruit softening and plant organ abscission. However, the members of <I>PG</I> gene family in sweetpotato (<I>Ipomoea batatas</I>) have not been extensively identified.</P><P><B>Results</B></P><P>In this study, there were 103 <I>PG</I> genes identified in sweetpotato genome, which were phylogenetically clustered into divergent six clades. The gene structure characteristics of each clade were basically conserved. Subsequently, we renamed these <I>PGs</I> according to their locations of the chromosomes. The investigation of collinearity between the <I>PGs</I> in sweetpotato and other four species, contained <I>Arabidopsis thaliana</I>, <I>Solanum lycopersicum</I>, <I>Malus domestica</I> and <I>Ziziphus jujuba</I>, revealed important clues about the potential evolution of the <I>PG</I> family in sweetpotato. Gene duplication analysis showed that <I>IbPGs</I> with collinearity relationships were all derived from segmental duplications, and these genes were under purifying selection. In addition, each promoter region of IbPG proteins contained <I>cis</I>-acting elements related to plant growth and development processes, environmental stress responses and hormone responses. Furthermore, the 103 <I>IbPGs</I> were differentially expressed in various tissues (leaf, stem, proximal end, distal end, root body, root stalk, initiative storage root and fibrous root) and under different abiotic stresses (salt, drought, cold, SA, MeJa and ABA treatment). <I>IbPG038</I> and <I>IbPG039</I> were down-regulated with salt, SA and MeJa treatment. According to the further investigation, we found that <I>IbPG006, IbPG034 and IbPG099</I> had different patterns under the drought and salt stress in fibrous root of sweetpotato, which provided insights into functional differences among these genes.</P><P><B>Conclusion</B></P><P>A total of 103 <I>IbPGs</I> were identified and classified into six clades from sweetpotato genome. The results of RNA-Seq and qRT-PCR suggested that <I>IbPG006</I>, <I>IbPG034</I> and <I>IbPG099</I> might play a significant role in tissue specificity as well as drought and salt stress responses, which showed valuable information for further functional characterization and application of the <I>IbPGs</I>.</P><P><B>Supplementary Information</B></P><P>The online version contains supplementary material available at 10.1186/s12870-023-04272-1.</P>