Constitutive overexpression of allene oxide cyclase in tomato ( Lycopersicon esculentum cv. Lukullus) elevates levels of some jasmonates and octadecanoids in flower organs but not in leaves

• Published in: Phytochemistry (Oxford) 2004-04, Vol.65 (7), p.847-856
• Main Authors: Miersch, Otto, Weichert, Heiko, Stenzel, Irene, Hause, Bettina, Maucher, Helmut, Feussner, Ivo, Wasternack, Claus
• Format: Article
• Language: English
• Subjects: Allene oxide cyclase; bioaccumulation; biochemical pathways; Biological and medical sciences; biosynthesis; Cyclopentanes - metabolism; Fatty Acids - chemistry; Fatty Acids - metabolism; Fatty Acids, Nonesterified - chemistry; Fatty Acids, Nonesterified - metabolism; Fatty Acids, Unsaturated - biosynthesis; Fatty Acids, Unsaturated - chemistry; Flower organs; flowers; Flowers - metabolism; Flowers - ultrastructure; free fatty acids; Fundamental and applied biological sciences. Psychology; Gene Expression; gene overexpression; Growth regulators; Immunohistochemistry; Intramolecular Oxidoreductases - biosynthesis; Intramolecular Oxidoreductases - genetics; Intramolecular Oxidoreductases - metabolism; isomerases; jasmonic acid; leaves; Lycopersicon esculentum - enzymology; Lycopersicon esculentum - genetics; Lycopersicon esculentum - metabolism; messenger RNA; Metabolism; octadecanoids; oxidoreductases; oxylipin; Oxylipin levels; Oxylipins; Plant Leaves - metabolism; Plant physiology and development; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; RNA, Messenger - biosynthesis; Solanum lycopersicum var. lycopersicum; Tissue Distribution; tomatoes; transgenic plants; Transgenic tomato plants; vegetable crops
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2004.01.016

The allene oxide cyclase (AOC), an enzyme in jasmonate biosynthesis, occurs in vascular bundles and ovules of tomato flowers which exhibit a tissue-specific oxylipin signature (Plant J. 24, 113-126, 2000). Constitutive overexpression of the AOC did not led to altered levels of jasmonates in leaves, but these levels increased upon wounding or other stresses suggesting regulation of jasmonate biosynthesis by substrate availability (Plant J. 33, 577-589, 2003). Here, we show dramatic changes in levels of jasmonic acid (JA), of 12-oxo-phytodienoic acid (OPDA), their methyl esters (JAME, OPDAME), and of dinor-OPDA in most flower organs upon constitutive overexpression of AOC. Beside a dominant occurrence of OPDAME and JA in most flower organs, the ratio among the various compounds was altered differentially in the organs of transgenic flowers, e.g. OPDAME increased up to 53-fold in stamen, and JA increased about 51-fold in buds and 7.5-fold in sepals. The increase in jasmonates and octadecanoids was accompanied by decreased levels of free lipid hydro(per)oxy compounds. Except for 16:2, the AOC overexpression led to a significant increase in free but not esterified polyunsaturated fatty acids in all flower organs. The data suggest different regulation of JA biosynthesis in leaves and flowers of tomato. Constitutive overexpression of the AOC increases in all flower organs levels of some jasmonates and octadecanoids, alters the ratios among the compounds, decreases levels of free lipid hydro(per)oxy compounds and increases levels of free but not of esterified polyunsaturated fatty acids.