Ectopic expression of the maize homeobox genes ZmHox1a or ZmHox1b causes pleiotropic alterations in the vegetative and floral development of transgenic tobacco.

Abstract

The ZmHox1a and ZmHox1b (for Zea mays homeobox) genes map on chromosomes 8 and 6, respectively. Both homeobox genes encode proteins that show 91% similarity and are transcribed simultaneously in meristematic and proliferating cells of the maize plant. To gain insight into the biological function of these genes, both open reading frames were expressed in tobacco, under the control of the cauliflower mosaic virus 35S promoter. The resulting transgenic ZmHox1a or ZmHox1b plants showed identical phenotypic alterations that fall into three classes: size reduction, formation of adventitious shoots, and homeotic floral transformations. Approximately 30% of the ZmHox1-expressing plants grew to only one-third of the wild-type size, and most axillary buds gave rise to lateral shoots. Flower abnormalities included formation of petaloid stamens and development of secondary flowers within the primary gynoecium. Therefore, the ectopic expression of the maize ZmHox1 homeobox gene products affects the vegetative as well as the reproductive phase of tobacco plants. All phenotypic alterations were transmitted to the next generation.

Attraction of the parasitoid Cotesia marginiventris to host (Spodoptera frugiperda) frass is affected by transgenic maize

“…Such changes include alteration of biochemical, physiological, and morphological traits unrelated to the intended genetic modification (Olesinski et al 1995;Ü berlacker et al 1996;Wang et al 1998;Lumbierres et al 2004). Particularly in reference to plant-produced volatiles used in plant-herbivore communication, one study uncovered consistent differences between GM and conventional crop cultivars in their attractiveness to herbivore females foraging for oviposition sites .…”

Loss of CLE40, a protein functionally equivalent to the stem cell restricting signal CLV3, enhances root waving in Arabidopsis

“…To express CLE40 from the CaMV35S promoter, the CLE40/Col cDNA was released from pMHAL1/14 by digestion with NotI and XbaI and cloned into the NotI and XbaI sites of pRTW/Not/Asc (Uberlacker et al 1996) to give pMHCL1. The cassette of pMHCL1 containing the fusion of the CaMV35S promoter, CLE40 cDNA and a nos terminator was then excised with AscI and cloned into the AscI site of pGPTV-BAR/AscI to give pMH35S-AL (35S:CLE40).…”

Radial axis differentiation in a globular embryo is marked by HAZ1, a PHD-finger homeobox gene of rice

“…It has a PHD-finger domain at a central portion and a homeodomain at a C-terminal portion, both of which are characteristic of the members of the PHD-finger family homeodomain proteins. There are putative nuclear localization signal repeats in an N-terminal portion and acidic regions between the PHD-finger domain and the homeodomain, both of which also exist in Zmhox1a/b and Zmhox2a/b (Klinge et al, 1996;Uberlacker et al, 1996). These overall structural features are very similar to Zmhox1 proteins (Fig.…”