Candidate gene selection and detailed morphological evaluations of fs8.1, a quantitative trait locus controlling tomato fruit shape

SUN, LIANG; RODRÍGUEZ, GUSTAVO RUBÉN; CLEVENGER, JOSH P; ILLA-BERENGUER, EUDALD; LIN, JINSHAN; BLAKESLEE, JOSHUA J; LIU, WENLI; FEI, ZHANJUN; WIJERATNE, ASELA; MEULIA, TEA; VAN DER KNAAP, ESTHER

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2015 vol. 20 p. 6471 - 6482

0022-0957

fs8.1 is a majorquantitative trait locus (QTL) that controls the elongated shape of tomato (Solanumlycopersicum) fruit. In this study, we fine-mapped the locus from a 47 Mbto a 3.03 Mb interval on the long arm of chromosome 8. Of the 122 annotatedgenes found in the fs8.1 region, 51 were expressed during floraldevelopment and six were differentially expressed in anthesis-stage ovaries in fs8.1and wild type (WT) lines. To identify possible nucleotide polymorphismsthat may underlie the fruit shape phenotype, genome sequence analyses betweentomato cultivars carrying the mutant and WT allele were conducted. This led tothe identification of 158 single nucleotide polymorphisms  (SNPs) and five small indels in the fs8.1interval, including 31 that could be associated with changes in geneexpression or function. Morphological and histological analyses showed that theeffects of fs8.1 were mainly on reproductive organ elongation by increasingcell number in the proximal-distal direction. Fruit weight was also increased infs8.1 compared to WT which was predominantly attributed to the increasedfruit length. By combining the findings from the different analyses, weconsider 12 likely candidate genes to underlie fs8.1, including Solyc08g062580encoding a pentatricopeptide repeat protein, Solyc08g061560 encodinga putative ortholog of ERECTA which is known to control fruit morphology andinflorescence architecture in Arabidopsis, Solyc08g061910 encoding aGTL2-like trihelix transcription factor, Solyc08g061930 encoding aprotein that regulates cytokinin degradation and two genes, Solyc08g062340 andSolyc08g062450 encoding 17.6 kDa class II small heat shock proteins.