Are we on the right track: Can our understanding of abscission in model systems promote or derail making improvements in less studied crops

Authors: PATTERSON, SARA - University Of Wisconsin; BOLIVAR-MEDINA, JENNY - University Of Wisconsin; FALBEL, TANYA - University Of Wisconsin; HEDTCKE, JANET - University Of Wisconsin; NEVAREZ-MCBRIDE, DANIELLE - University Of Wisconsin; MAULE, ANDREW - University Of Wisconsin; Zalapa, Juan

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2015
Publication Date: 1/26/2016
Publication URL: https://handle.nal.usda.gov/10113/62761
Citation: Patterson, S.E., Bolivar-Medina, J.L., Falbel, T.G., Hedtcke, J.L., Nevarez-McBride, D., Maule, A.F., Zalapa, J.E. 2016. Are we on the right track: Can our understanding of abscission in model systems promote or derail making improvements in less studied crops? Frontiers in Plant Science. 6(1268). doi: 10.3389/fpls.2015.01268.

Interpretive Summary: Historically berry drop or abscission has not been a trait that either grape or cranberry breeders have focused on improving. However, with the recent focus on conservation of water and resources and the introduction of new cold-hardy hybrid grapes, berry drop has become an issue in both crops. With wine grapes, early abscission results in lower sugar content and higher acidity, and thus a poorer quality wine in general. Alternatively, in table grapes it is even more important to retain high quality full clusters after harvest. Uncontrolled berry drop decreases both value and quality. In cranberry, there has been minimal research regarding abscission, but it is believed that cultural and environmental factors such as limited nutrient availability and extreme heat conditions can cause fruit drop. Growers have placed a new emphasis on management of water and sustainable production in response to climate change and new environmental stresses. Consequently, the loss of fruit is an important issue as fruit growth and abscission is most likely dependent on transport of water, nutrients and other factors across the abscission zone. We searched available databases for both grapes and cranberries for 15 genes previously identified in other plant species. We identified matches for all fifteen of the genes we searched for in both grape and cranberry genomes. In general, the high similarity of both cranberry and grape genes to known abscission-related genes suggests that there may be shared functions and similar signaling pathways regulating the abscission process that could be further studied to inform and improve breeding efforts. Clearly, it is essential that breeders and molecular biologists work together providing an understanding of the unique development of each species as well as the targeted genes or pathways of interest. Ultimately, improving our understanding of both early and late fruit abscission in these fruit crops using molecular tools combined with traditional breeding, morphological and physiological studies will lead to better management practices and improved quality and greater yields.

Technical Abstract: As the world population grows and resources and climate conditions change, crop improvement continues to be one of the most important challenges for agriculturalists. The yield and quality of many crops is affected by abscission or shattering, and environmental stresses often hasten or alter the abscission process. Understanding this process can not only lead to genetic improvement, but also changes in cultural practices and management that will contribute to higher yields, improved quality and greater sustainability. As plant scientists, we have learned significant amounts about this process through the study of model plants such as Arabidopsis, tomato, rice, and maize. While these model systems have provided significant valuable information, we are sometimes challenged to use this knowledge effectively as variables including the economic value of the crop, the uniformity of the crop, ploidy levels, flowering and crossing mechanisms, ethylene responses, cultural requirements, responses to changes in environment, and cellular and tissue specific morphological differences can significantly influence outcomes. The value of genomic resources for lesser-studied crops such as cranberries and grapes and the orphan crop fonio will also be considered.