Accepted_test

Discovery of 16(S)-Lipoxygenase/16-hydroperoxide lyase pathway in green tissues of cucumber (Cucumis sativus L.) plants
by Gorina S. | Lantsova N. | Iljina T. | Egorova A. | Toporkova Y. | Grechkin A. | Kazan Institute of Biochemistry and Biophysics – Subdivision of the Federal State budgetary Institution of Science “Kazan Scientific Center of the Russian Academy of Sciences” | Kazan Institute of Biochemistry and Biophysics – Subdivision of the Federal State budgetary Institution of Science “Kazan Scientific Center of the Russian Academy of Sciences” | Kazan Institute of Biochemistry and Biophysics – Subdivision of the Federal State budgetary Institution of Science “Kazan Scientific Center of the Russian Academy of Sciences” | Kazan Institute of Biochemistry and Biophysics – Subdivision of the Federal State budgetary Institution of Science “Kazan Scientific Center of the Russian Academy of Sciences” | Kazan Institute of Biochemistry and Biophysics – Subdivision of the Federal State budgetary Institution of Science “Kazan Scientific Center of the Russian Academy of Sciences” | Kazan Institute of Biochemistry and Biophysics – Subdivision of the Federal State budgetary Institution of Science “Kazan Scientific Center of the Russian Academy of Sciences”
Abstract ID: 492
Event: BGRS-abstracts
Sections: [Sym 6] Section “Genomics, genetics and systems biology of plants”

Hydroperoxide lyase (HPL) belongs to the non-classical cytochromes P450 of the CYP74 family, which, unlike most P450 monooxygenases, do not require molecular oxygen and redox partners for their catalytic activity. Substrates, hydroperoxides of polyunsaturated fatty acids, act as donors of oxygen and electrons. HPL and lipoxygenase (LOX) form the HPL-branch of the LOX pathway, leading to the formation of C6 and C9 aldehydes and alcohols, as well as ω-oxoacids. These compounds play important roles in plant-plant and plant-herbivore interactions, function as signals activating systemic defense, and are involved directly in plant defense as antimicrobials and fungicides. A number of these compounds are specifically named Green Leaf Volatiles (GLVs). They cause a characteristic odor that occurs when leaves are crushed or otherwise injured. They are valuable chemicals that are used in the food and perfume industries.

Plant LOXs are classified as 9- or 13-LOXs according to the products of positional specific oxygenation. Thus, there are 9- and 13-HPL branches of the LOX pathway. GLVs are formed during the 13-LOX/HPL branch.

We have discovered a new branch of metabolism in the transformation of linole(n)ic acids, namely the 16-LOX/HPL branch. The cucumber plants as well as the recombinant cucumber HPL CYP74B6 possessed unprecedented 16-HPL activity, cleaving 16-HPOT into a C15 fragment, 15-oxo-9,12-pentadecadienoic acid, and a complementary volatile C3 fragment, propionic aldehyde. The 16-LOX/16-HPL route of oxylipin biosynthesis presents a novel facet of the plant LOX pathway.