ARS | Publication request: Gene expression profiles of auxin metabolism in maturing apple fruit

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 2012
Publication Date: September 30, 2012
Citation: Shin, S.B., Mattheis, J.P., Evans, K., Zhu, Y. 2012. Gene expression profiles of auxin metabolism in maturing apple fruit. Meeting Abstract.

Technical Abstract: Variation exists among apple genotypes in fruit maturation and ripening patterns that influences at-harvest fruit firmness and postharvest storability. Based on the results from our previous large-scale transcriptome profiling on apple fruit maturation and well-documented auxin-ethylene crosstalk, the current experiment was designed to understand the molecular events related to auxin metabolism during fruit development and their interactions with ethylene pathways. Maturity-defined weekly apple fruit samples of four cultivars with distinct ripening phenotypes were aligned according to their physiological maturity. The expression of eight candidate genes with annotated functions of auxin transport, GH3 and auxin response were profiled by qPCR for at least 10 consecutive weeks; and the weekly samples with similar Ct values selected as calibrator of relative expression level for better across-genotype comparability. Most of these genes showed dynamic regulation during fruit development and differential expression among genotypes. The peak expression of auxin transporter MdPIN1-1 correlated with the detection of the transcripts of a pre-climacteric ethylene biosynthesis gene MdACS3. Both transcript profiles during maturation and tissue-specific expression features for these genes suggested that auxin transport and homeostasis are important in regulating the timing of ethylene pathway activation and therefore may contribute to distinct ripening processes among apple genotypes.