A deletion affecting an LRR-RLK gene co-segregates with the fruit flat shape trait in peach

Abstract

In peach, the fat phenotype is caused by a partially dominant allele in heterozygosis (Ss), fruits from homozygous trees (SS) abort a few weeks after fruit setting. Previous research has identifed a SSR marker (UDP98–412) highly associated with the trait, found suitable for marker assisted selection (MAS). Here we report a ∼10 Kb deletion afecting the gene PRUPE.6G281100, 400 Kb upstream of UDP98-412, co-segregating with the trait. This gene is a leucine-rich repeat receptor-like kinase (LRRRLK) orthologous to the Brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) group. PCR markers suitable for MAS confrmed its strong association with the trait in a collection of 246 cultivars. They were used to evaluate the DNA from a round fruit derived from a somatic mutation of the fat variety ‘UFO-4’, revealing that the mutation afected the fat associated allele (S). Protein BLAST alignment identifed signifcant hits with genes involved in diferent biological processes. Best protein hit occurred with AtRLP12, which may functionally complement CLAVATA2, a key regulator that controls the stem cell population size. RT-PCR analysis revealed the absence of transcription of the partially deleted allele. The data support PRUPE.6G281100 as a candidate gene for fat shape in peach.