Evaluation of Kazakh dandelions, a novel root crop and latex source, as a source of pentadecanoic acid, a recently identified essential fatty acid

Commodities

Practices

Dietary C15FA reportedly can prevent metabolic syndrome and fatty liver disease in people. In contrast, fatty acids with one more (C16FA) or less (C14FA) carbon atom may cause inflammation. Human C15FA levels in high-altitude blue zones are triple the levels found elsewhere due to C15FA enriched dairy products produced by local ruminants. Other populations have less dietary access to C15FA. Common dandelion pollen is a known low-altitude C15FA source, but C15FA levels in other dandelion parts are not well described. 

Taraxacum kok-saghyz (TKS) is a Kazakh (aka Russian) dandelion variety that accumulates latex in roots. Kultevat is engineering and developing this novel row crop as a domestic rubber source. TKS is known to produce some C15FA, but the distribution, quantity, and ratio of C15FA to other FA are not known. If C15FA is relatively abundant in dandelion flowers or leaves, then farmers could harvest these parts for human or dairy feed, potentially increasing population access to dietary C15FA. We propose to quantify C15FA production by TKS, distribution within TKS, and stability under various growing and processing conditions. This is a preliminary step that should be followed by testing in dairy production if results are favorable.

We propose to grow TKS and common dandelions under various greenhouse and field conditions, and analyze fatty acid and latex distribution at relevant harvest times. Greenhouse plants will grow in tall, narrow plastic pots (2” x 2” x 12”) that allow deep taproots.Greenhouse conditions will compare extreme physical, chemical, and biological differences between media. Media will include heavy clay soil, sandy riparian soil, garden soil managed conventionally, garden soil managed regeneratively, Miracle Gro potting mix, and Horticulchar, a biologically very active potting media made on the farm. Each of these 6 media will be tested in triplicate with TKS. Miracle Gro and Horticulchar will be tested in triplicate with common dandelions.

Field plants will grow in ten plots that we have maintained for six years for soil management experiments. The base soil is an alfisol. One pair of plots is no-till with solarization for weed control. The second is similar but with tillage. The third uses a heavily mulched market garden strategy. The fourth uses cover crops and tillage. The fifth uses herbicides for weed control. In each pair of plots, one plot is managed more organically (e.g. heavy application of vermicompost and deficient trace elements) and one plot is managed more conventionally (e.g. following extension service NPK recommendations). We will plant 100 square feet of TKS dandelions in each plot, and 10 square feet of common dandelions in the fourth and fifth pairs of plots. 

Independent variables: We will conduct routine chemical soil tests and microbiometer assays on each potting medium and each plot. Microbiometer assays report the level of microbial activity and the division between bacterial and fungal activity. 

Dependent variables: We will collect flowers when they emerge, and the remainder of the plant when roots would be harvested for latex. We will collect samples from three plants in each greenhouse and field condition, dry, and quantify the C14FA, C15FA, C16FA, C17FA, C18FA, and latex in roots, leaves, and whole flowers ((10 plots + 6 media) x 3 plants x 3 parts = 144 assays of dried material). From the fourth and fifth pairs of field plots we also will collect and analyze a multi-plant pollen sample from TKS (4 pollen assays); collect, freeze, and analyze leaves and flowers of three plants (24 fresh frozen assays); and collect, ferment, freeze, and analyze leaves and flowers of three plants (24 fermented assays). Plant tops will be fermented with cabbage in a sauerkraut making process. The total number of samples is 196.

Samples will be analyzed by Dr. Lin at the University of Missouri in Columbia, MO. His laboratory will extract and esterify fatty acids, then identify C14-18FA using gas chromatography and mass spectroscopy. 

Dr. Sumner will apply a random forest machine learning algorithm (available through Google Colab and in the R statistics program), to identify independent variables and plant parts that predict C15FA levels in tissues. We expect biologically robust growth conditions to predict high levels of C15FA in flowers and pollen. 

Objectives

• Identify the TKS and common dandelion parts containing the highest level of C15FA and the highest ratios of (C15FA + C17FA) to (C14FA + C16FA + C18FA)
• Determine the degree to which the chemistry and biology of growing conditions influences C15FA accumulation and odd to even chain fatty acid ratios, ie by ranking variable importance in the random forest model.
• Calculate the minimum quantity of dandelion parts required to deliver 40 mcg of C15FA in a human diet (about twice currently estimated consumption).
• Calculate the C15FA that a dairy ruminant would ingest by eating dandelion tops from 100 square feet of farmland.