Cranberry fruit epicuticular wax benefits and identification of a wax-associated molecular marker

Authors: ERNDWEIN, LINDSAY - Oak Ridge Institute For Science And Education (ORISE); Kawash, Joseph; JOHNSON-CICALESE, JENNIFER - Rutgers University; VORSA, NICHOLI - Rutgers University; Polashock, James

Submitted to: BMC Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2023
Publication Date: 4/5/2023
Citation: Erndwein, L., Kawash, J.K., Johnson-Cicalese, J., Vorsa, N., Polashock, J.J. 2023. Cranberry fruit epicuticular wax benefits and identification of a wax-associated molecular marker. BMC Plant Biology. https://doi.org/10.1186/s12870-023-04207-w.
DOI: https://doi.org/10.1186/s12870-023-04207-w

Interpretive Summary: As the global climate changes, periods of environmental stress throughout the North American cranberry growing regions will become more common. One consequence of high temperature extremes and drought conditions is sunscald. Scalding damages the developing berry and reduces yields through fruit tissue damage and/or increasing secondary pathogen infection. Naturally occurring wax on the surface of the fruit may be a promising feature to enhance to reduce sunscald in cranberry. In this study, we found that cranberries with high fruit surface wax have reduced water loss in storage and maintain a lower surface temperature following heat/light exposure as compared to fruit with low wax. A region in the genome of cranberry was identified that is associated with the level of fruit wax deposition. A test was then developed to determine if a given cranberry plant is likely to produce fruit with low or high wax. This test will assist cranberry breeding efforts to develop more climate-tolerant cranberries. This work serves to advance the genetic improvement of cranberry crops in the face of global climate change and will be useful to breeders of cranberry and other small fruit crops.

Technical Abstract: As the global climate changes, periods of abiotic stress throughout the North American cranberry growing regions will become more common. One consequence of high temperature extremes and drought conditions is sunscald. Scalding damages the developing berry and reduces yields through fruit tissue damage and/or increasing secondary pathogen infection. Irrigation is the primary approach to controlling sunscald. However, it is water-use intensive and can increase fungal-incited fruit rot. Epicuticular wax functions as a barrier to various environmental stresses in other fruit crops and may be a promising feature to enhance to mitigate sunscald in cranberry. In this study we assessed the function of epicuticular wax in cranberries to attenuate stresses associated with sunscald by subjecting high and low epicuticular wax cranberries to controlled desiccation in an incubator and irradiation with high light. Cranberries with high epicuticular wax lost fewer mass percent and maintained a lower surface temperature following heat/light and desiccation experiments as compared to fruit with low wax. A cranberry population that segregates for epicuticular wax was phenotyped for epicuticular fruit wax levels and genotyped using genotyping by sequencing (GBS). Quantitative trait loci analyses of these data identified a QTL associated with epicuticular wax phenotype. A SNP marker was developed in the QTL region for marker assisted selection. A candidate gene associated with epicuticular wax (Glossy 1) was also identified in this QTL region. Our results suggest that increased cranberry epicuticular wax load may help reduce the effects of heat/light and water stress: two primary contributors to sunscald. Further, the molecular marker identified in this study can be used in marker assisted selection to identify cranberry progeny with potentially high fruit epicuticular wax while the plants are still seedlings. This work serves to advance the genetic improvement of cranberry crops in the face of global climate change.