ARS | Publication request: DEHYDROZALUZANN C, A NATURAL SESQUITERPENOLIDE, CAUSES RAPID PLASMA MEMBRANE LEAKAGE

Submitted to: Phytochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 20, 1999
Publication Date: N/A

Interpretive Summary: Isolation and determination of the mode of action of natural phytotoxins is an important approach to the discovery of environmentally benign herbicides. Dehydrozaluzanin C, a natural phytotoxic sesquiterpene, caused rapid plasma membrane leakage. Dehydrozaluzanin C is more active than the synthetic herbicide acifluorfen. The compound also reduced plant growth, but at higher concentrations. A strong reversal effect on both growth and membrane leakage is caused by reduced glutathione. Photosynthetic, respiratory, and mitotic processes, as well as NADH oxidase activity appear to be unaffected by this compound. There appeared to be some involvement of amino acid synthesis with the effects on root growth. Our results indicate that dehydrozaluzanin C exerts its effects on plants through two different mechanisms: one related to the plasma membrane leakage effect and another that reduces growth through a different mechanism.

Technical Abstract: Dehydrozaluzanin C, a natural phytotoxic sesquiterpene lactone, causes rapid plasma membrane leakage. Dehydrozaluzanin C is more active at 50 uM than the same concentration of the herbicide acifluorfen. Reversal of this compound's inhibitory effects on root growth are found for the amino acids histidine, glycine, proline, and the mixtures (aspartic acid + glutamic acid + alanine), (phenylalanine + tyrosine + tryptophane),and (cysteine + methionine). A strong reversal effect is obtained also with glutathione, which is able to minimize the leakage effect observed. Photosynthetic, respiratory, and mitotic processes, as well as NADH oxidase appear to be unaffected by this compound. Our results indicate that dehydrozaluzanin C exerts its effects on plants through two different mechanisms: one related with the plasma membranes leakage effect and another that reduces growth through a different mechanism.