Control of targeted turnover of key ethylene hormone signaling pathway proteins to modulate ethylene sensitivity in plants

Abstract

A gene expression system for controllable expression of ethylene response in a plant cell includes an activation cassette comprising a DNA-binding domain that recognizes a response element; an ecdysone receptor ligand binding domain; and an activation domain; and a target cassette comprising an inducible promoter, which comprises, in operative association, the response element and a minimal promoter responsive to the activation domain. The inducible promoter controls the expression of a nucleic acid sequence that encodes a selected regulatory protein that modifies sensitivity to ethylene of certain signal proteins in the plant. Interaction among the components of the activation cassette and target cassette, when in a plant cell, in the presence of an inducing composition, increases expression of the selected regulatory protein, and in turn decreases expression and accumulation of the signal protein in the plant, thereby and decreasing ethylene sensitivity in the plant cell. This increase in the expression of the regulatory protein, particularly in the presence of ethylene, is controlled by the timing, the concentration and the duration of the application of the inducing composition. Transgenic plant cells, tissues, organs and entire plants are provided, which in the presence of the inducing composition control ethylene sensitivity. Ethylene sensitivity and / or ethylene production in such transgenic plants and tissues may be controlled for purposes of manipulating ripening, flower senescence and other ethylene sensitive functions of the plant.

Description

Background of the invention [0001] The plant hormone ethylene is a signaling molecule that regulates many physiological processes in the plant life cycle, including during germination, flower and fruit development, and plant responses to various environmental stressors such as drought, heat, salt Overdose and disease responses (see, eg, Chen et al., 2005, Annals of Botany, 95:901-915; Czarny et al., 2006 Biotechnol. Adv., 24:410-419). Ethylene biosynthetic pathways and signaling / regulatory pathways and networks are well known. For example, see figure 1 and 2 , Wang et al., "Ethylene Biosynthesis and Signaling Networks", "The Plant Cell", 2002 (edited by the American Society of Plant Biologists), p. Pages S131-S151. [0002] In plants, several key steps in the ethylene signaling pathway are highly regulated. As for the EIN2 (ethylene insensitive 2) and EIN3 (ethylene insensitive 3) proteins, their expression is induced by ethylene, which leads to an increased ethylene resp...

AI Technical Summary

Problems solved by technology

These deficiencies include: use of toxic or volatile inducers, low induction levels, poor translocation / mobility in plants, slow ability to "turn off" gene expression, or insufficient specificity for non-toxic inducers in plants, etc.

Induction of ethylene insensitivity at will and maintenance for a predetermined time frame has not been successfully achieved in the prior art

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