Plant Science ：抗夜蛾的转基因西红柿

生物谷报道：来自泰国Suranaree  科技大学和美国路易斯安那州立大学的科学家研发了对夜蛾抗性增强的西红柿品种。这些转基因品种表达土豆中编码的多酚氧化酶（PPO）基因。该种基因已被证实可催化酚类物质转化成醌类物质，这些次级代谢产物可使植物具有假单胞杆菌抗菌性。

夜蛾在转PPO基因的西红柿品种中生长速率是其在非转基因品种中的四分之一。高表达PPO还可以增加夜蛾幼虫死亡率，并在其发育的第3阶段减少其食量。研究结果显示PPO介导的酚氧化反应在抵抗害虫中起关键作用。

文章发表在《植物杂志》上，详情请见  http://dx.doi.org/10.1016/j.plantsci.2008.01.006（国际农业生物技术周报）

生物谷推荐原文参考：

Plant Science
Volume 174, Issue 4, April 2008, Pages 456-466

Overexpression of tomato polyphenol oxidase increases resistance to common cutworm

Siraprapa Mahanila, Jutharat Attajarusita, Michael J.Stoutb and Piyada Thipyaponga, ,
aSchool of Crop Production Technology, Suranaree University of Technology, 111 University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand
bDepartment of Entomology, 402 Life Sciences Building, Louisiana State University, Baton Rouge, LA 70803, USA
Received 23 May 2007;  revised 7 January 2008;  accepted 11 January 2008.  Available online 21 January 2008.

Abstract

Polyphenol oxidases (PPOs), which catalyze the oxidation of phenolics to quinones, have been reported to confer resistance to Pseudomonas syringae and are thought to be involved in insect resistance. To assess the impact of PPO expression on resistance to the common cutworm (Spodoptera litura (F.)) (Lepidoptera: Noctuidae), we used transgenic tomato (Lycopersicon esculentum Mill.) plants constitutively expressing sense- and antisense-oriented potato PPO genes. Transgenic plants expressing a sense PPO construct (overexpressing PPO [OP] plants) exhibited 2.0–5.7-fold higher PPO activity levels, whereas antisense PPO transgenic plants (suppressed PPO [SP] plants) exhibited 1.5–7.3-fold lower PPO activity levels than nontransformed controls. The PPO-overexpressing transgenic plants clearly showed an increase in resistance; simple growth rates of common cutworms on OP plants were up to 2.5 and 3.3 times lower than on controls and SP leaves, respectively, and larvae consumed less foliage. In addition, increased PPO activity led to higher larval mortality. The efficiency of conversion of ingested food and efficiency of conversion of digested food of third instars were found to be significantly different among tomato genotypes with differing PPO activity levels, suggesting that PPO activity rendered foliage less nutritious. Moreover, when leaflets at nodes 4 and 8 of SP, NT and OP plants were detached and fed to common cutworm larvae, their PPO activity levels were induced 1.6–2.2-fold. These results suggest a critical role for PPO-mediated phenolic oxidation in resistance to this insect. Manipulation of PPO activity could provide resistance simultaneously to both disease and insect pests, and therefore might be used as a component of effective integrated pest management.  

Corresponding author. Tel.: +66 44 224276; fax: +66 44 224281

 

 

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