Transcriptomics of differential ripening in ‘d’Anjou pear (Pyrus communis L.)

Authors: Honaas, Loren; Hargarten, Heidi; HADISH, JOHN - Washington State University; FICKLIN, STEPHEN - Washington State University; SERRA, SARA - Washington State University; MUSACCHI, STEFANO - Washington State University; WAFULA, ERIC - Pennsylvania State University; Mattheis, James; DEPAMPHILIS, CLAUDE - Pennsylvania State University; Rudell, David

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2021
Publication Date: 6/16/2021
Citation: Honaas, L.A., Hargarten, H.L., Hadish, J., Ficklin, S., Serra, S., Musacchi, S., Wafula, E., Mattheis, J.P., dePamphilis, C., Rudell Jr, D.R. 2021. Transcriptomics of differential ripening in ‘d’Anjou pear (Pyrus communis L.). Frontiers in Plant Science. 12. Article 609684. https://doi.org/10.3389/fpls.2021.609684.
DOI: https://doi.org/10.3389/fpls.2021.609684

Interpretive Summary: For pears to meet consumer expectations, the fruit must have specific qualities relating to appearance, flavor, and texture. Even though pears are picked in late summer and early fall, they can be marketed months after harvest. This is because of advances in pear storage that allow fruit quality to be maintained for many months. Current postharvest technology mainly slows down ripening allowing for long-term storage, but pears need to resume ripening to achieve acceptable fruit quality, especially textural changes (like softened fruit flesh) that consumers expect. However, producers lack reliable tools to predict fruit quality and ripening capacity for pears during and after storage. Our report describes a novel approach that we used to discover hundreds of genes (and groups of genes) that might be useful biomarkers - that is - tools that producers can use to predict future fruit quality. With sufficient development, these biomarkers might be used to guide postharvest supply chain decisions, which could reduce costs by avoiding losses and increasing efficiency.

Technical Abstract: Estimating maturity in pome fruits is a critical task that directs virtually all postharvest supply chain decisions. This is especially important for European pear varieties because losses due to spoilage and senescence must be minimized while ensuring proper ripening capacity is achieved (in part by satisfying a fruit chilling requirement). However, reliable methods are lacking for accurate estimation of pear fruit maturity - specifically with regard to predicting ripening capacity. In this study we examined a contrast of fruit maturity in ‘d’Anjou’ pear (Pyrus communis) by sorting fruit based on canopy position, and further classifying the fruit based on index of absorbance difference (IAD). We then dug deeper by exploring a fine fruit quality contrast with transcriptome sequencing to discover gene expression differences in fruit that had different fruit quality characteristics at harvest and into the postharvest period. While gene activity changes in pear fruit during 8 months of controlled-atmosphere (CA) storage were massive, we discovered smaller-scale, phased gene activity signatures that distinguished fruit with different ripening characteristics. Functional profiles of these genes concur with previous findings, and also offer new clues, and thus hypotheses, about genes involved in pear fruit quality, maturity, and ripening. Finally, this work may lead to new tools for enhanced postharvest management based on activity of gene co-expression modules, rather than individual genes, that may have utility within specific windows of time during postharvest management of ‘d’Anjou’ pear.