Relationship between glutamate accumulation and ethylene synthesis in tomato fruit during ripening

• Published in: Okayama Daigaka Nogakubu gakujutsu hokuku no. 84
• Main Authors: Inaba, A. (Okayama Univ. (Japan). Faculty of Agriculture), Nakatsuka, A, Kubo, Y, Nakamura, R
• Format: Journal Article
• Language: Japanese
• Published: 01.02.1995
• Subjects: ACIDE GLUTAMIQUE; ACIDO GLUTAMICO; ETHYLENE; ETILENO; FRUIT; FRUTO; LYCOPERSICON ESCULENTUM
• ISSN: 0474-0254

The effect of ethylene on the accumulation of glutamate in the fruit of normal tomato ("Rutgers" and "Momotaro") and ripening inhibitor mutant (rin) tomato (Lycopersicon esculentum Mill.) during ripening was investigated. As fruit ripening progressed, glutamate content in the fruit pericarp tissue increased greatly in "Rutgers" but remained low and at constant level in ring tomato. Glutamine and gamma-aminobutyric acid contents decreased gradually during ripening in both "Rutgers" and rin fruit. Relatively high activities of glutamate dehydrogenase, glutamate synthase and glutamine synthetase were detected throughout fruit ripening in both varieties, whereas no relationship was observed between glutamate content and the enzyme activities. Treatment of "Momotaro" fruit with diazocyclopentadiene, an inhibitor of ethylene action, inhibited the increase in ethylene production and glutamate accumulation which are associated with fruit ripening, suggesting that glutamate accumulation may be mediate through ethylene. However, glutamate content in rin fruit treated with exogenous ethylene remained low and unchanged until after four days. The results indicate that accumulation of glutamate in tomato fruit is likely to be related to the ripening process apart from the direct role of ethylene