<i>Endopolygalacturonase</i> Gene Polymorphisms: Asset of the Locus in Different Peach Accessions

Endopolygalacturonase(endoPG) plays a pivotal role in determining peach [Prunus persica L.(Batsch)] fruit characteristics. Different Pp-endoPG genes or allelic variants have been described, characterized by differentpolymorphisms: insertions-deletions (InDels) and single nucleotidepolymorphisms (SNPs). Eighty-five peach accessions (comprisingcommercial cultivars, F1 progenies of selected crosses, and threehaploid seedlings) with different flesh softening patterns(Non Melting: NM; Melting: M; Slow Softening: SS; Stony Hard: SH) were screenedby exploiting specific polymorphisms, with the aim to characterize their assetat the endoPG locus and evaluate apotential relationship with fruit flesh texture phenotype. The results of InDel analysis allowed to distinguish, by a simple genotyping procedure, NM fleshphenotypes from the others. Further information arose from this analysis, showing that two Pp-endoPG genes, i.e., Pp-endoPGm (Ppa006839m), involved in the determination of the Melting/Non Meltingtrait, and Pp-endoPG_M (Ppa006857m), involved in the determination of the Clingstone/Freestone trait, always co-segregate,and that SS Big Top possesses a “null” Pp-endoPG allele. Cleaved AmplifiedPolymorphic Sequence (CAPS) analysis allowed to preliminarilydiscriminate the Pp-endoPG variantsof the SS and SH accessions considered. The integrated use of the consideredpolymorphisms in a high number of peach accessions proved useful, by individuatingthe different gene variants and their combinations, to describe the structureof the endoPG locus in differentgenotypes.