Overexpression of a petunia zinc-finger gene alters cytokinin metabolism and plant forms
Shoot branching and plant height are among the key factors that define the overall architecture of plants. We found that overexpression of a cDNA for a zinc-finger protein of petunia, designated Lateral shoot- Inducing Factor (LIF), in transgenic petunia plants resulted in a dramatic increase in lateral shoots and reduced plant height. LIF overexpression also caused a decrease in the number of cells in the stem, leaf, and flower, accompanied by enlargement of cells. trans-Zeatin was decreased while N6-(Δ2-isopentenyl)adenine was increased in the leaves of LIF-overexpressed petunia. Most of the riboside, ribotide, and glucoside forms were also increased. Expression analysis using a LIF::GUS fusion gene and RT-PCR suggested that LIF is specifically expressed around the bases of axillary buds and weakly in basal part of flowers in wild-type petunia. GFP-LIF-GUS fusion proteins were translocated into the nucleus when transiently expressed in onion epidermal cells. LIF overexpression resulted in enhanced branching also in tobacco and Arabidopsis, indicating the conservation of the response to LIF overexpression among dicotyledonous plants. On the basis of these results we discuss about possible functions of LIF.
Document Type: Research Article
Affiliations: 1: Developmental Biology Laboratory, Plant Physiology Department, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan 2: Plant Science Center, RIKEN, 1-7-22 Suehiro, Tsurumi, Yokohama 230-0045, Japan 3: National Institute of Vegetable and Tea Science, 360 Kusawa, Ano, Age, Mie 514-2392, Japan 4: Leaf Tobacco Research Center, Japan Tobacco Inc., 1900 Idei, Oyama, Tochigi 323-0808, Japan 5: National Institute of Floricultural Science, Fujimoto 2-1, Tsukuba, Ibaraki 305-8519, Japan 6: Faculty of Agriculture, Tottori University, Koyama-Minami 4-101, Tottori, Tottori 680-0945, Japan 7: Research School of Chemistry, Australian National University, GPO Box 4, Canberra, ACT 2601, Australia
Publication date: February 1, 2005