Next Article in Journal
Synthesis and Biological Activity of Some Novel Derivatives of 4-Amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole
Next Article in Special Issue
Characterization of Phenolic Compounds in Pinus laricio Needles and Their Responses to Prescribed Burnings
Previous Article in Journal
Heterocycles [h]Fused onto 4-Oxoquinoline-3-Carboxylic Acid, Part IV. Convenient Synthesis of Substituted Hexahydro [1,4]Thiazepino[2,3-h]quinoline-9-carboxylic Acid and Its Tetrahydroquino[7,8-b]benzothiazepine Homolog
Previous Article in Special Issue
Leishmanicidal and Cholinesterase Inhibiting Activities of Phenolic Compounds from Allanblackia monticola and Symphonia globulifera

Functional Analysis of Polyphenol Oxidases by Antisense/Sense Technology

Suranaree University of Technology, 111 University Ave., Muang District, Nakhon Ratchasima 30000, Thailand
Department of Entomology, Louisiana State University, 402 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803, USA
Author to whom correspondence should be addressed.
Molecules 2007, 12(8), 1569-1595;
Received: 30 May 2007 / Revised: 19 July 2007 / Accepted: 19 July 2007 / Published: 27 July 2007
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Polyphenol oxidases (PPOs) catalyze the oxidation of phenolics to quinones, the secondary reactions of which lead to oxidative browning and postharvest losses of many fruits and vegetables. PPOs are ubiquitous in angiosperms, are inducible by both biotic and abiotic stresses, and have been implicated in several physiological processes including plant defense against pathogens and insects, the Mehler reaction, photoreduction of molecular oxygen by PSI, regulation of plastidic oxygen levels, aurone biosynthesis and the phenylpropanoid pathway. Here we review experiments in which the roles of PPO in disease and insect resistance as well as in the Mehler reaction were investigated using transgenic tomato (Lycopersicon esculentum) plants with modified PPO expression levels (suppressed PPO and overexpressing PPO). These transgenic plants showed normal growth, development and reproduction under laboratory, growth chamber and greenhouse conditions. Antisense PPO expression dramatically increased susceptibility while PPO overexpression increased resistance of tomato plants to Pseudomonas syringae. Similarly, PPO-overexpressing transgenic plants showed an increase in resistance to various insects, including common cutworm (Spodoptera litura (F.)), cotton bollworm (Helicoverpa armigera (Hübner)) and beet army worm (Spodoptera exigua (Hübner)), whereas larvae feeding on plants with suppressed PPO activity had higher larval growth rates and consumed more foliage. Similar increases in weight gain, foliage consumption, and survival were also observed with Colorado potato beetles (Leptinotarsa decemlineata (Say)) feeding on antisense PPO transgenic tomatoes. The putative defensive mechanisms conferred by PPO and its interaction with other defense proteins are discussed. In addition, transgenic plants with suppressed PPO exhibited more favorable water relations and decreased photoinhibition compared to nontransformed controls and transgenic plants overexpressing PPO, suggesting that PPO may have a role in the development of plant water stress and potential for photoinhibition and photooxidative damage that may be unrelated to any effects on the Mehler reaction. These results substantiate the defensive role of PPO and suggest that manipulation of PPO activity in specific tissues has the potential to provide broad-spectrum resistance simultaneously to both disease and insect pests, however, effects of PPO on postharvest quality as well as water stress physiology should also be considered. In addition to the functional analysis of tomato PPO, the application of antisense/sense technology to decipher the functions of PPO in other plant species as well as for commercial uses are discussed. View Full-Text
Keywords: Antisense; disease resistance; insect resistance; Lycopersicon esculentum Mill;Mehler reaction; polyphenol oxidase; sense; transgenic. Antisense; disease resistance; insect resistance; Lycopersicon esculentum Mill;Mehler reaction; polyphenol oxidase; sense; transgenic.
Show Figures

Figure 1

MDPI and ACS Style

Thipyapong, P.; Stout, M.J.; Attajarusit, J. Functional Analysis of Polyphenol Oxidases by Antisense/Sense Technology. Molecules 2007, 12, 1569-1595.

AMA Style

Thipyapong P, Stout MJ, Attajarusit J. Functional Analysis of Polyphenol Oxidases by Antisense/Sense Technology. Molecules. 2007; 12(8):1569-1595.

Chicago/Turabian Style

Thipyapong, Piyada, Michael J. Stout, and Jutharat Attajarusit. 2007. "Functional Analysis of Polyphenol Oxidases by Antisense/Sense Technology" Molecules 12, no. 8: 1569-1595.

Find Other Styles

Article Access Map by Country/Region

Only visits after 24 November 2015 are recorded.
Back to TopTop