Targeted Glucosinolate Conversion: How Kohlrabi Tissues Produce Health-Promoting Compounds

New IGZ Study Highlights Tissue-Specific Enzyme Activity to Enhance Plant Protection and Health Benefits

A research team at the Leibniz Institute for Vegetable and Ornamental Crops (IGZ) has analyzed how glucosinolates, health-promoting plant compounds, are broken down within various tissues of the kohlrabi plant. The findings reveal that the enzymes myrosinase and “specifier” proteins in leaves, stems, and bulb tissues determine whether breakdown products are generated that can support human health as well as enhance the plant’s pest resistance. These insights could help to specifically increase the health benefits and pest resistance of kohlrabi.

Kohlrabi and other vegetables of the Brassica genus contain glucosinolates—bioactive plant compounds known for their health benefits to humans and their protective function against pests and diseases. Researchers at IGZ have investigated how the activity of specific enzymes in different tissues controls the conversion of glucosinolates. The goal of this research is to gain new insights that can specifically enhance the health and protective value of these vegetables.

The study showed that glucosinolate conversion in the leaves, stems, and different parts of the bulb occurs in tissue-specific ways. Leafy tissues and inner bulb tended to form the less bioactive nitriles, whereas conversion in the leaf stalk, bulb peel, stem and root produced a higher proportion of isothiocyanates, which are known for their health-promoting properties. This tissue-specific control of glucosinolate hydrolysis is due to the distribution and activity of myrosinase and “specifier” proteins, which vary across plant parts and thus influence the distribution of the resulting breakdown products.

To determine glucosinolate composition and breakdown products, the scientists used chromatographic and mass spectrometric techniques. In nine tissue types—including leaves, stems, and various bulb layers—they examined the activity of myrosinase and other specifying proteins to fully characterize the tissue-specific conversion processes.

The results of the study could provide new approaches for breeding and processing of kohlrabi and other Brassica vegetables and improve our understanding of how plants adapt to their environment. Targeted cultivation and adapted processing could promote the formation of health-promoting isothiocyanates, which would further increase the nutritional benefits of these vegetables.

Future research should take a closer look at the importance of the “specifier” proteins in particular for the plant in order to better understand their role in plant health.

The full article was published in the journal Food Chemistry:

Mbudu, K.G.; Witzel, K.; Börnke, F; Hanschen, F.S. (2024). Glucosinolate profile and specifier protein activity determine the glucosinolate hydrolysis product formation in kohlrabi (Brassica oleracea var. gongylodes) in a tissue-specific way. Food Chemistry. DOI: 10.1016/j.foodchem.2024.142032.

Wissenschaftlicher Ansprechpartner:
Dr. habil. Franziska Hanschen, Forschungsgruppenleiterin | E-Mail hanschen@igzev.de |
Tel. +49 (0) 33701 - 78 250

Originalpublikation:
https://doi.org/10.1016/j.foodchem.2024.142032 Mbudu, K.G.; Witzel, K.; Börnke, F; Hanschen, F.S. (2024). Glucosinolate profile and specifier protein activity determine the glucosinolate hydrolysis product formation in kohlrabi (Brassica oleracea var. gongylodes) in a tissue-specific way. Food Chemistry. DOI: 10.1016/j.foodchem.2024.142032

Weitere Informationen:
http://Targeted Glucosinolate Conversion: How Kohlrabi Tissues Produce Health-Promoting Compounds.
http://New IGZ Study Highlights Tissue-Specific Enzyme Activity to Enhance Plant Protection and Health Benefits: