Fruit softening in melting-flesh peaches is triggered by a major accumulation of ethylene at the late stage of ripening. Existence of stony hard peaches showing inhibition of fruit softening has been correlated with low levels of indole-3-acetic-acid inducing low levels of ethylene, but the underlying molecular cause remains unknown. Using ultra-performance liquid chromatography and tandem mass spectrometry, the authors identified a defect in indole-3-pyruvic-acid accumulation, an indole-3-acetic-acid intermediate. This originates from the loss of YUCCA gene expression, encoding the enzyme mediating the conversion from indole-3-pyruvic-acid to indole-3-acetic-acid. The authors have identified a homozygous transposon insertion located in the YUCCA flanking region found uniquely in stony hard peaches, and observed co-segregation of the insertion with the phenotype, pinpointing YUCCA loss of expression as the main cause of the softening defect. (Summary by Matthias Benoit).
Plant Journal 10.1111/tpj.14070