Auxin polar transport is essential for the development of zygote and embryo in Nicotiana tabacum L. and correlated with ABP1 and PM H+-ATPase activities

Abstract

Auxin is an important plant growth regulator, and plays a key role in apical–basal axis formation and embryo differentiation, but the mechanism remains unclear. The level of indole-3-acetic acid (IAA) during zygote and embryo development of Nicotiana tabacum L. is investigated here using the techniques of GC-SIM-MS analysis, immunolocalization, and the GUS activity assay of DR5::GUS transgenic plants. The distribution of ABP1 and PM H+-ATPase was also detected by immunolocalization, and this is the first time that integral information has been obtained about their distribution in the zygote and in embryo development. The results showed an increase in IAA content in ovules and the polar distribution of IAA, ABP1, and PM H+-ATPase in the zygote and embryo, specifically in the top and basal parts of the embryo proper (EP) during proembryo development. For information about the regulation mechanism of auxin, an auxin transport inhibitor TIBA (2,3,5-triiodobenzoic acid) and exogenous IAA were, respectively, added to the medium for the culture of ovules at the zygote and early proembryo stages. Treatment with a suitable IAA concentration promoted zygote division and embryo differentiation, while TIBA treatment obviously suppressed these processes and caused the formation of abnormal embryos. The distribution patterns of IAA, ABP1, and PM H+-ATPase were also disturbed in the abnormal embryos. These results indicate that the polar distribution and transport of IAA begins at the zygote stage, and affects zygote division and embryo differentiation in tobacco. Moreover, ABP1 and PM H+-ATPase may play roles in zygote and embryo development and may also be involved in IAA signalling transduction.

Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants

“…Auxin-inducible reporter DR5-GUS transgenic plants are frequently used to indicate the level of auxins in plant tissues (Chen et al, 2010a;Song et al, 2013). We found that the GUS staining in roots was more intense in Fe-deficient conditions than in Fesufficient conditions, indicating that Fe deficiency increases auxin levels in roots (Supplemental Fig.…”

Source of nitrogen as a factor limiting saponin production by hairy root and suspension cultures of Calendula officinalis L.

“…It is essential for the formation of meristems and plant growth. Number of reviews and reports focused on this topic: Yeung and Stasolla (2000), Souter and Lindsey (2000), van Berkel et al (2013), Chen et al (2010), and Elhiti and Stasolla (2011). Strong embryogenesis initiator, 2.4-D, was accumulated in tissue, where it was slowly deactivated.…”

Regulation of Petunia Pollen Tube Growth by Phytohormones: Identification of Their Potential Targets

“…Inhibition of auxin transport impaired the organization of actin in zygotes of the brown alga Fucus and inhibited signal-induced developmental polarity [29]. Auxin polar transport is essential for the development of zygote and embryo, and was correlated with ABP1 and PM H + -ATPase activities [16]. Recently, it was found that the PM-located transmembrane kinase (TMK), receptor-like kinase (RLK), is capable of interacting with ABP1, thereby transducing auxin signal to activate PM-associated Rho of plants (ROPs).…”