Abstract
Inflorescence regeneration in vitro provides a simplified approach for the study of inflorescence development. In this study, high frequency of regenerated inflorescences was established using Arabidopsis stage-10 pistil as the explants on the inducing medium containing the 2 mg/L zeatin and 0.01 mg/L indole-3-acetic acid. TERMINAL FLOWER 1 (TFL1) expression was detected in callus at 6 days after transferred to inducing medium, and LEAFY (LFY) expression was detectable subsequently, suggesting that both genes play important roles as they function on inflorescence development in the plant. To investigate the formation of the stem cell organizing center, we examined the WUSCHEL (WUS) and CLAVATA3 (CLV3) expression within callus during inflorescence regeneration. WUS signals start to accumulate on callus at 4 days after induction, and then, the CLV3 signals are induced on callus at 5 days on the inflorescence-inducing medium. The expression domain of WUS is below that of CLV3, indicating that the patterns of the organizing center and stem cell formation are similar to that in zygotic and somatic embryogenesis. However, more cells of the organizing center were observed within callus than pro-embryo, suggesting that inflorescence differentiation requires more cells of the organizing center. Furthermore, it was found that the WUS expression is controlled by the ratio of cytokinin with auxin. The results suggest that other factors besides WUS and CLV3 are required for inflorescence regeneration.
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References
An YR, Li XG, Su HY, Zhang XS (2004) Pistil induction by hormones from the callus of Oryza sativa in vitro. Plant Cell Rep 23:448–452
Bradley D, Ratcliffe O, Vincent C, Carpenter R, Coen E (1997) Inflorescence commitment and architecture in Arabidopsis. Science 275:80–83
Conti L, Bradley D (2007) TERMINAL FLOWER1 is a mobile signal controlling Arabidopsis architecture. Plant Cell 19:767–778
Gordon SP, Heisler MG, Reddy GV, Ohno C, Das P, Meyerowitz EM (2007) Pattern formation during de novo assembly of the Arabidopsis shoot meristem. Development 134:3539–3548
Guan CM, Zhu SS, Li XG, Zhang XS (2006) Hormone-regulated inflorescence induction and TFL1 expression in Arabidopsis callus in vitro. Plant Cell Rep 25:1133–1137
Huala E, Sussex IM (1992) LEAFY interactes with floral homeotic genes to regulate Arabidopsis floral development. Plant Cell 4:901–903
Jack T (2004) Molecular and genetic mechanisms of floral control. Plant Cell 16:S1–S17
Laux T, Mayer KFX, Berger J, Jurgens G (1996) The WUSCHEL gene is required for shoot and floral meristem integrity in Arabidopsis. Development 122:87–96
Li QZ, Li XG, Bai SN, Lu WL, Zhang XS (2002) Isolation of HAG1 and its regulation by plant hormones during in vitro floral organogenesis in Hyacinthus orientalis L. Planta 215:533–540
Mayer KF, Schoof H, Haecker A, Lenhard M, Jurgens G, Laux T (1998) Role of WUSCHEL in regulating stem cell fate in the Arabidopsis shoot meristem. Cell 95:805–815
Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol Plant 5(3):473–497
Okada K, Ueda J, Komaki MK, Bell CJ, Shimura Y (1991) Requirement of the auxin polar transport system in early stages of Arabidopsis floral bud formation. Plant Cell 3:677–684
Scheres B (2007) Stem-cell niches: nursery rhymes across kingdoms. Nat Rev Mol Cell Biol 8:345–354
Schoof H, Lenhard M, Haecker A, Mayer KF, Jurgens G, Laux T (2000) The stem cell population of Arabidopsis shoot meristems in maintained by a regulatory loop between the CLAVATA and WUSCHEL genes. Cell 100:635–644
Shani E, Yanai O, Ori N (2006) The role of hormones in shoot apical meristem function. Curr Opin Plant Biol 9:484–489
Shannon S, Meeks-Wagner DR (1991) A mutation in the Arabidopsis TFL1 gene affects inflorescence meristem development. Plant Cell 3:877–892
Shimizu-Sato S, Tanaka M, Mori H (2009) Auxin–cytokinin interactions in the control of shoot branching. Plant Mol Biol 69:429–435
Skoog F, Miller CO (1957) Chemical regulation of growth and organ formation in plant tissues cultured in vitro. Symp Soc Exp Biol 11:118–131
Smyth DR, Bowman JL, Meyerowitz EM (1990) Early flower development in Arabidopsis. Plant Cell 2:755–767
Su YH, Zhao XY, Liu YB, Zhang CL, O’Neill SD, Zhang XS (2009) Auxin-induced WUS expression is essential for embryonic stem cell renewal during somatic embryogenesis in Arabidopsis. Plant J 59:448–460
Tanaka H, Dhonukshe P, Brewer PB, Friml J (2006a) Spatiotemporal asymmetric auxin distribution: a means to coordinate plant development. Cell Mol Life Sci 63:2738–2754
Tanaka M, Takei K, Kojima M, Sakakibara H, Mori H (2006b) Auxin controls local cytokinin biosynthesis in the nodal stem in apical dominance. Plant J 45:1028–1036
Vieten A, Sauer M, Brewer PB, Friml J (2007) Molecular and cellular aspects of auxin-transport-mediated development. Trends Plant Sci 12:160–168
Wu BH, Zheng YL, Liu DC, Zhou YH, Yan ZH (2003) Unisexual pistillate flower regeneration in immature embryo culture of wheat. Acta Bot Sin 45:452–459
Xu HY, Li XG, Li QZ, Bai SN, Lu WL, Zhang XS (2004) Characterization of HoMADS1 and its induction by plant hormones during in vitro development in Hyacinthus orientalis L. Plant Mol Biol 55:209–220
Xu YY, Wang XM, Li J, Li JH, Wu JS, Walker JC, Xu ZH, Chong K (2005) Activation of the WUS gene induces ectopic initiation of floral meristems on mature stem surface in Arabidopsis thaliana. Plant Mol Biol 57:773–784
Zhao Y (2008) The role of local biosynthesis of auxin and cytokinin in plant development. Curr Opin Plant Biol 11:16–22
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This research is supported by grants from the Ministry of Science and Technology (MOST) of China (2007CB948200) and the National Natural Science Foundation (NNSF) of China (30770217).
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Communicated by K. Chong.
Z. J. Cheng, S. S. Zhu and X. Q. Gao contributed equally to this paper.
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Cheng, Z.J., Zhu, S.S., Gao, X.Q. et al. Cytokinin and auxin regulates WUS induction and inflorescence regeneration in vitro in Arabidopsis . Plant Cell Rep 29, 927–933 (2010). https://doi.org/10.1007/s00299-010-0879-8
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DOI: https://doi.org/10.1007/s00299-010-0879-8