The role of cytokinin during Arabidopsis gynoecia and fruit morphogenesis and patterning

Departamento de Biotecnología y Bioquímica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, km 9.6 Libramiento Norte, Carretera Irapuato-León, Irapuato, Guanajuato, Mexico, Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato, Mexico, and Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, km 9.6 Libramiento Norte, Carretera Irapuato-León, Irapuato, Guanajuato, Mexico.
The Plant Journal (Impact Factor: 5.97). 05/2012; 72(2):222-234. DOI: 10.1111/j.1365-313X.2012.05062.x
Source: PubMed


Cytokinins have many essential roles in embryonic and post-embryonic growth and development, but their role in fruit morphogenesis is currently not really known. Moreover, information about the spatio-temporal localization pattern of cytokinin signaling in gynoecia and fruits is lacking. Therefore, the synthetic reporter line TCS::GFP was used to visualize cytokinin signaling during gynoecium and fruit development. Fluorescence was detected at medial regions of developing gynoecia, and, unexpectedly, at the valve margin in developing fruits, and was severely altered in mutants that lack or ectopically acquire valve margin identity. Comparison to developing gynoecia and fruits in a DR5rev::GFP line showed that the transcriptional responses to cytokinin and auxin are frequently present in complementary patterns. Moreover, cytokinin treatments in early gynoecia produced conspicuous changes, and treatment of valve margin mutant fruits restored this tissue. The results suggest that the phytohormone cytokinin is important in gynoecium and fruit patterning and morphogenesis, playing at least two roles: an early proliferation-inducing role at the medial tissues of the developing gynoecia, and a late role in fruit patterning and morphogenesis at the valve margin of developing fruits.

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Available from: Stefan De Folter
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    • "Recently, there is increased interest in gynoecium development, especially in the characterization of GFP fluorescence of gene fusions or marker lines (e.g., Girin et al., 2011; Marsch-Martinez et al., 2012; Larsson et al., 2014; Martinez-Fernandez et al., 2014; Moubayidin and Ostergaard, 2014; Zuniga-Mayo et al., 2014). However, fluorescence "
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    • "The differentiation of the DZ is under the control of intricate regulatory networks involving multiple transcription factors. Recent investigations in pod dehiscence regulation have uncovered another layer of the regulatory network that include phytohormones in specifying the DZs (Sorefan et al., 2009; Arnaud et al., 2010; Marsch-Martinez et al., 2012). "
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    • "The Nemhauser model has been very useful to frame the role of different players in Arabidopsis carpel development, but conclusive proof of the proposed auxin gradient has never been obtained. Actually, detailed descriptions of auxin accumulation throughout gynoecium development using a DR5rev::GFP reporter have shown that auxin maxima are formed in the apical domain, first as isolated foci and later as a continuous apical ring, while the proposed gradient cannot be observed (Girin et al., 2011; Marsch-Martinez et al., 2012a; Larsson et al., 2013). In addition, several recent studies indicate that the dynamics of auxin accumulation, homeostasis and response within the developing gynoecium are highly complex and we are still far from fully comprehending how positional information is translated into developmental outputs in gynoecium differentiation (Sohlberg et al., 2006; Ståldal et al., 2008; Ståldal and Sundberg, 2009; Marsch-Martinez et al., 2012b). "
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