Fine mapping an AUXIN RESPONSE FACTOR, SmARF18, as a candidate gene of the PRICKLE LOCUS that controls prickle absence/presence on various organs in eggplant (Solanum melongena L.)

Abstract

Prickle is a sharp protrusion that covering plant and fruit calyxes of eggplant are considered undesirable agronomic traits, for they bring troubles and create additional costs for farmers. However, 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 candidate gene encoded by Pl, which possesses a non-synonymous single nucleotide polymorphism co-segregating with prickle phenotype in F2 population. The finding here could provide a basis to reveal the molecular regulatory mechanism of prickle morphogenesis in plants and breed prickle-free eggplant cultivars.