Modification of Plant Architecture in Chrysanthemum by Ectopic Expression of theTonacco Phytochrome

Modification of Plant Architecture in Chrysanthemum by Ectopic Expression of theTonacco Phytochrome

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
19 J. A MER . S OC . H ORT . S CI . 126(1):19–26. 2001. J. A MER . S OC . H ORT . S CI . 126(1):19–26. 2001. Modification of Plant Architecture in Chrysanthemum by Ectopic Expression of the Tobacco Phytochrome B1 Gene Zhi-Liang Zheng 1 Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH 43210 Zhenbiao Yang 2 Departmen of plant Biology and Plant Biotechnology Center, The Ohio State University, Columbus, OH 43210 Jyan-Chyan Jang 3 and James D. Metzger 4 Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH 43210 A DDITIONAL INDEX WORDS . short-day plant, branch angle, stem height control, red light, gibberellin, growth regulator, night break, Dendranthema × grandiflora A BSTRACT . Height control is a major consideration during commercial production of chrysanthemum [ Dendranthema × grandiflora Kitam. (syn. Chrysanthemum × morifolium Ramat.)]. We have addressed this problem by a biotechnological approach. Plants of ‘Iridon’ chrysanthemum were genetically engineered to ectopically express a tobacco ( Nicotiana tabacum L.) phytochrome B1 gene under the control of the CaMV 35S promoter. The transgenic plants were shorter in stature and had larger branch angles than wild type (WT) plants. Reduction in growth caused by the ectopic expression of the tobacco phytochrome B1 gene was similar to that caused using a commercial growth retardant at the recommended rate. Another morphological effect observed in the leaves of the transgenic plants was more intense green color that was related to higher levels of chlorophyll. The transgenic plants appeared very similar to WT plants grown under a filter that selectively attenuated far red wavelengths. Furthermore, when plants were treated either with gibberellin A 3 (which promoted growth) or 2-chlorocholine chloride, an inhibitor of gibberellin biosynthesis (which inhibited growth) the difference in the average internode length between the transgenic plants and WT plants was the same in absolute terms. This suggests that reduction of growth by the expressed PHY-B1 transgene did not directly involve gibberellin biosynthesis. The commercial application of this biotechnology could provide an economic alternative to the use of chemical growth regulators, thereby reducing production costs. economic necessity for growers (Gianfagna, 1995). Height control in greenhouse crops is achieved by several approaches. The most common practice is the use of chemical growth regulators (Dole and Wilkins, 1999). Most commercial growth retardants reduce stem growth by inhibiting gibberellin (GA) biosynthesis, thereby reducing the endogenous levels of one or more biologically active GAs (Gianfagna, 1995). How- ever, this method necessitates significant economic inputs by the grower in terms of both the cost of chemicals and the labor required for application. Furthermore, in many countries, syn- thetic chemical growth regulators for height control are not labeled for use in crops destined for human consumption. Cultural methods are also used to control the height of green-
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/01/2009 for the course HORT hor-11-12 taught by Professor Park during the Spring '09 term at A.T. Still University.

Page1 / 8

Modification of Plant Architecture in Chrysanthemum by Ectopic Expression of theTonacco Phytochrome

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online