Developmental and Feedforward Control of the Expression of Folate Biosynthesis Genes in Tomato Fruit  

作　　者：Jeffrey C. Wallera Tariq A. Akhtar Aurora Lara-Nunez Jesse F. Gregory lli Ryan R McQuinn James J. Giovannoni Andrew D. Hanson 

机构地区：[1]Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA [2]Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA [3]United States Department of Agriculture-Agricultural Research Service and Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA

出　　处：《Molecular Plant》2010年第1期66-77,共12页分子植物（英文版）

摘　　要：Little is known about how plants regulate their folate content, including whether the expression of folate biosynthesis genes is orchestrated during development or modulated by folate levels. Nor is much known about how folate levels impact the expression of other genes. These points were addressed using wild-type tomato fruit and fruit engineered for high folate content. In wild-type fruit, the expression of genes specifying early steps in folate biosynthesis declined during development but that of other genes did not. In engineered fruit overexpressing foreign GTP cyclohy- drolase I and aminodeoxychorismate synthase genes, the expression of the respective endogenous genes did not change, but that of three downstream pathway genes--aminodeoxychorismate lyase, dihydroneopterin aldolase, and mitochondrial folylpolyglutamate synthase--respectively increased by up to 7.8-, 2.8-, and 1.7-fold, apparently in response to the build-up of specific folate pathway metabolites. These results indicate that, in fruit, certain folate pathway genes are developmentally regulated and that certain others are subject to feedforward control by pathway intermediates. Micro- array analysis showed that only 14 other transcripts （of 11 000 surveyed） increased in abundance by two-fold or more in high-folate fruit, demonstrating that the induction of folate pathway genes is relatively specific.Little is known about how plants regulate their folate content, including whether the expression of folate biosynthesis genes is orchestrated during development or modulated by folate levels. Nor is much known about how folate levels impact the expression of other genes. These points were addressed using wild-type tomato fruit and fruit engineered for high folate content. In wild-type fruit, the expression of genes specifying early steps in folate biosynthesis declined during development but that of other genes did not. In engineered fruit overexpressing foreign GTP cyclohy- drolase I and aminodeoxychorismate synthase genes, the expression of the respective endogenous genes did not change, but that of three downstream pathway genes--aminodeoxychorismate lyase, dihydroneopterin aldolase, and mitochondrial folylpolyglutamate synthase--respectively increased by up to 7.8-, 2.8-, and 1.7-fold, apparently in response to the build-up of specific folate pathway metabolites. These results indicate that, in fruit, certain folate pathway genes are developmentally regulated and that certain others are subject to feedforward control by pathway intermediates. Micro- array analysis showed that only 14 other transcripts （of 11 000 surveyed） increased in abundance by two-fold or more in high-folate fruit, demonstrating that the induction of folate pathway genes is relatively specific.

关 键 词：Folate biosynthesis fruit development metabolic engineering transcript profiling. 

分 类 号：TQ465.92[化学工程—制药化工] TP273[自动化与计算机技术—检测技术与自动化装置]