Abstract
We examined the effect of ectopic expression of WUS on the morphology of tobacco seedlings and the segments in vitro. WUS was amplified from Arabidopsis cDNA and introduced into the tobacco genome under the transcriptional control of the β-estradiol-inducible expression system. When 1-week-old transgenic seedlings were cultured in the presence of β-estradiol, only the root tip region developed bulbous tissues followed by shoot formation and plant regeneration, suggesting its applicability for improving the strategy of micropropagation in recalcitrant species. Evident abnormality was not observed in the cotyledons, hypocotyl nor root except for the tip. However, ectopic WUS seemed to be functional in those parts through the observation of gene expression and the behavior of cultured segments. Small root segments with a root tip treated with β-estradiol also showed bulbing but no shoots unless exogenous cytokinin was supplied. These findings suggest the existence of unknown factors regulating ectopic WUS function in the seedling.
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Acknowledgments
We thank Prof. N-H. Chua (Rockefeller University) for his kind gift of the plasmid pER8, harboring the XVE expression system. We thank S. Nagata and S. Hayashi for their cooperation in the study.
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Communicated by F. Sato.
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299_2007_342_MOESM1_ESM.tif
[Segment culture of non-transgenic tobacco seedlings. Young seedlings were cut into segments; cotyledon, hypocotyl, root and root tip with RAM, and were cultured on LS agar medium with or without b-estradiol in the dark for three weeks. Those segments were arranged in the order from cotyledon to root tip. Neither root generation nor root growth was inhibited by b-estradiol in wild-type tobacco]
299_2007_342_MOESM2_ESM.tif
[Fluorescent microscopic observation of a root tip region of XVE::H3sGFP line. A young seedling was treated with b-estradiol (1 mM) for 24 h. Note the presence of green fluorescence in the nuclei of the whole organ (right)]
299_2007_342_MOESM3_ESM.tif
[XVE::WUS seedlings showing severe abnormality in the light condition. Transgenic seeds were sown on the medium with b-estradiol and kept for 20 d in the light]
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Rashid, S.Z., Yamaji, N. & Kyo, M. Shoot formation from root tip region: a developmental alteration by WUS in transgenic tobacco. Plant Cell Rep 26, 1449–1455 (2007). https://doi.org/10.1007/s00299-007-0342-7
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DOI: https://doi.org/10.1007/s00299-007-0342-7