Simultaneous Transgenic Suppression of LePG and LeExp1 Influences Rheological Properties of Juice and Concentrates from a Processing Tomato Variety
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- 作者：Mary S. Kalamaki ; Mark H. Harpster ; Joseph M. Palys ; John M. Labavitch ; David S. Reid ; and David A. Brummell
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2003
- 出版时间：December 3, 2003
- 年：2003
- 卷：51
- 期：25
- 页码：7456 - 7464
- 全文大小：151K
- 年卷期：v.51,no.25(December 3, 2003)
- ISSN：1520-5118
文摘
Processing tomato lines suppressed in the accumulation of ripening-related polygalacturonase orexpansin were generated by introduction of transgenes to silence expression of the LePG and LeExp1genes, respectively. The rheological properties of juice and juice reconstituted from paste producedfrom lines suppressed in one of these genes, or in both, were compared with azygous controls. Whenassayed by measuring Bostwick consistency, paste produced from either suppressed LePG orsuppressed LeExp1 lines and diluted to 5 
ges/entities/deg.gif">Brix was approximately 18% more viscous than thatproduced from controls. Simultaneous suppression of LePG and LeExp1 produced a small additionalincrease in viscosity of 4%. Rheometric flow analysis at 5 or 10 ges/entities/deg.gif">Brix also showed substantial increasesin the consistency index due to suppression of either LePG or LeExp1 alone, and a small additionalincrease when both genes were suppressed in the same transgenic line. Measurements by laserdiffraction and [1H]NMR showed that suppression of LePG or LeExp1 accumulation altered the sizedistribution of insoluble particles and modified their surface properties. The data are consistent withsuppression of LePG increasing serum viscosity, and suppression of either LePG or LeExp1 alteringthe properties of the insoluble particles and improving some aspect of particle-particle or particle-serum interaction, or both. However, relative to that caused by suppression of either gene alone, theadditional increase in viscosity caused by simultaneous suppression of LePG and LeExp1 togetherwas slight.Keywords: Expansin; Lycopersicon esculentum; polygalacturonase; tomato juice; tomato paste;viscosity