Differential iridoid production as revealed by a diversity panel of 84 cultivated and wild blueberry species

Abstract

Cultivated blueberry (Vaccinium corymbosum, Vaccinium angustifolium, Vaccinium darrowii, and Vaccinium virgatum) is an economically important fruit crop native to North America and a member of the Ericaceae family. Several species in the Ericaceae family including cranberry, lignonberry, bilberry, and neotropical blueberry species have been shown to produce iridoids, a class of pharmacologically important compounds present in over 15 plant families demonstrated to have a wide range of biological activities in humans including anti-cancer, anti-bacterial, and anti-inflammatory. While the antioxidant capacity of cultivated blueberry has been well studied, surveys of iridoid production in blueberry have been restricted to fruit of a very limited number of accessions of V. corymbosum, V. angustifolium and V. virgatum; none of these analyses have detected iridoids. To provide a broader survey of iridoid biosynthesis in cultivated blueberry, we constructed a panel of 84 accessions representing a wide range of cultivated market classes, as well as wild blueberry species, and surveyed these for the presence of iridoids. We identified the iridoid glycoside monotropein in fruits and leaves of all 13 wild Vaccinium species, yet only five of the 71 cultivars. Monotropein positive cultivars all had recent introgressions from wild species, suggesting that iridoid production can be targeted through breeding efforts that incorporate wild germplasm. A series of diverse developmental tissues was also surveyed in the diversity panel, demonstrating a wide range in iridoid content across tissues. Taken together, this data provides the foundation to dissect the molecular and genetic basis of iridoid production in blueberry.

Genetic diversity assessed by genotyping by sequencing (GBS) and for phenological traits in blueberry cultivars

“…Blueberries have a high concentration of phenolic compounds and anthocyanins [ 5 ], which are known for their high antioxidant capacity that neutralizes free radicals and can potentially provide protection against carcinogenicity, cardiovascular and neurodegenerative changes associated with aging [ 6 , 7 , 8 ]. In certain blueberry cultivars (cvs) high concentrations of iridoid glycosides, a large group of secondary metabolites with potential human health benefits, have also been identified [ 9 ].…”

Breeding Cultivars from Blueberry × Deerberry Hybrids: Progress and Prospects

“…Plants that produce iridoids have a history of use in traditional medicine in treating inflammatory conditions (Viljoen et al, 2012). Leisner et al (2017) measured iridoid content in the berries of 84 Vaccinium accessions, including many Cyanococcus cultivars and several wild species from other sections. Of the 71 Cyanococcus cultivars sampled, 'Ozarkblue' had the greatest iridoid content measured as monotropein (113 ng • mg -1 dry fruit weight).…”

Utilizing Plant Synthetic Biology to Improve Human Health and Wellness

“…This can also reduce some of the important nutraceutical compounds found in the foods that we eat. For example, there is a complete lack of iridoids, a class of monoterpenes suggested to benefit human health, in most cultivated varieties of blueberry on the market, while every wild species tested was abundant with them ( Leisner et al, 2017 ). While this was an inadvertent consequence of breeding, it illustrates the need to investigate wild relatives of food crops to identify nutraceuticals lost during domestication.…”