Fine mapping a single nucleotide transversion in AUXIN RESPONSE FACTOR 18 controls prickle absence/presence on various organs in eggplant (Solanum melongena L.)

Abstract

Eggplant is an important fruit vegetable from the Solanaceae family, with rich nutrition and palatability. Prickles covering plant and fruit calyxes of eggplant are considered undesirable agronomic traits, for they bring trouble and create additional costs for farmers. Prickle is a sharp protrusion that is common in plants, but little is known about its regulatory genes and molecular mechanism of morphogenesis. In this study, two eggplant inbred lines, prickly ‘140’ and prickleless ‘145’ were applied to construct F1 , BC1 , and F2 offspring populations. Genetic analysis results showed that prickle’s absence/presence on various organs in eggplant was controlled by only one dominant nuclear gene. The PRICKLE LOCUS ( Pl ) was fine mapped into a candidate interval with 28.3 Kb on chromosome 6 ultimately by adopting bulked segregant analysis combined with genome walking strategy. An auxin response factor SmARF18 ( Smechr0602826.1 ) was deduced to be a reliable candidate gene encoded by Pl , with a non-synonymous SNP (single nucleotide polymorphism) occurring at the 1633rd nucleotide within the second exon, which encoded the middle region of the protein. The finding here could provide a basis to reveal the molecular regulatory mechanism of prickle morphogenesis in plants and breed prickle-free eggplant cultivars.