The WUSCHELa (PtoWUSa) is Involved in Developmental Plasticity of Adventitious Root in Poplar

WUSCHEL-RELATED HOMEOBOX (WOX) transcription factors play critical roles in cell fate determination during plant development. As the founding member of the WOX family, WUSCHEL (WUS) is characterized for its role in maintaining stem cell in meristem. In this study, we investigated the function of Populus tomentosa WUSCHELa (PtoWUSa) in adventitious roots (ARs) in poplar. Expression profile analysis showed that PtoWUSa was not only expressed in shoot apical meristem and stem, but also expressed in ARs. Ectopic expression of PtoWUSa in Arabidopsis resulted in shortened primary root, as well as agravitropism and multiple branches. Overexpression of PtoWUSa in poplar increased the number of ARs but decreased their length. Moreover, the AR tip and lateral root tip became larger and swollen. In addition, the expression of auxin transporter genes PIN-FORMED were downregulated in ARs of transgenic plant. Taken together, these results suggest that PtoWUSa could be involved in AR development in poplar through regulating the polar auxin transport in ARs.

Download Full-text

Early development and gravitropic response of lateral roots in Arabidopsis thaliana

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2011.0231 ◽

2012 ◽

Vol 367 (1595) ◽

pp. 1509-1516 ◽

Cited By ~ 30

Author(s):

S. Guyomarc'h ◽

S. Léran ◽

M. Auzon-Cape ◽

F. Perrine-Walker ◽

M. Lucas ◽

...

Keyword(s):

Lateral Root ◽

Developmental Plasticity ◽

Lateral Roots ◽

Expression Patterns ◽

Primary Root ◽

Root System Architecture ◽

Specific Response ◽

Root Induction ◽

Root Gravitropism ◽

Auxin Transporter

Root system architecture plays an important role in determining nutrient and water acquisition and is modulated by endogenous and environmental factors, resulting in considerable developmental plasticity. The orientation of primary root growth in response to gravity (gravitropism) has been studied extensively, but little is known about the behaviour of lateral roots in response to this signal. Here, we analysed the response of lateral roots to gravity and, consistently with previous observations, we showed that gravitropism was acquired slowly after emergence. Using a lateral root induction system, we studied the kinetics for the appearance of statoliths, phloem connections and auxin transporter gene expression patterns. We found that statoliths could not be detected until 1 day after emergence, whereas the gravitropic curvature of the lateral root started earlier. Auxin transporters modulate auxin distribution in primary root gravitropism. We found differences regarding PIN3 and AUX1 expression patterns between the lateral root and the primary root apices. Especially PIN3, which is involved in primary root gravitropism, was not expressed in the lateral root columella. Our work revealed new developmental transitions occurring in lateral roots after emergence, and auxin transporter expression patterns that might explain the specific response of lateral roots to gravity.

Download Full-text

The Ca2+ sensor protein CMI1 fine tunes root development, auxin distribution and responses

10.1101/488536 ◽

2018 ◽

Author(s):

Ora Hazak ◽

Elad Mamon ◽

Meirav Lavy ◽

Hasana Sternberg ◽

Smrutisanjita Behera ◽

...

Keyword(s):

Root Growth ◽

Root Development ◽

Lateral Root ◽

Developmental Plasticity ◽

Molecular Mechanisms ◽

Ectopic Expression ◽

Growth Arrest ◽

Root Hairs ◽

Root Tip ◽

Auxin Distribution

Signaling cross-talks between auxin, a regulator of plant development and Ca2+, a universal second messenger have been proposed to modulate developmental plasticity in plants. However, the underlying molecular mechanisms are largely unknown. Here we report that in Arabidopsis roots, auxin elicits specific Ca2+ signaling pattern that spatially coincide with the expression pattern of auxin-regulated genes. We identified the EF-hand protein CMI1 (Ca2+ sensor Modulator of ICR1) as an interactor of the ROP effector ICR1 (Interactor of Constitutively active ROP). CMI1 is monomeric in solution, changes its secondary structure at Ca2+ concentrations ranging from 10-9 to 10-8 M and its interaction with ICR1 is Ca2+ dependent, involving a conserved hydrophobic pocket. cmi1 mutants display an increased auxin response including shorter primary roots, longer root hairs, longer hypocotyls and altered lateral root formation while ectopic expression of CMI1 induces root growth arrest and reduced auxin responses at the root tip. When expressed alone, CMI1 is localized at the plasma membrane, the cytoplasm and in nuclei. Interaction of CMI1 and ICR1 results in exclusion of CMI1 from nuclei and suppression of the root growth arrest. CMI1 expression is directly upregulated by auxin while expression of auxin induced genes is enhanced in cmi1 concomitantly with repression of auxin induced Ca2+ increases in the lateral root cap and vasculature, indicating that CMI1 represses early auxin responses. Collectively, our findings identify a crucial function of Ca2+ signaling and CMI1 in root growth and suggest an auxin-Ca2+ regulatory feedback loop that fine tunes root development.

Download Full-text

Members of the YABBY gene family specify abaxial cell fate in Arabidopsis

Development ◽

10.1242/dev.126.18.4117 ◽

1999 ◽

Vol 126 (18) ◽

pp. 4117-4128 ◽

Cited By ~ 15

Author(s):

K.R. Siegfried ◽

Y. Eshed ◽

S.F. Baum ◽

D. Otsuga ◽

G.N. Drews ◽

...

Keyword(s):

Gene Family ◽

Cell Fate ◽

Apical Meristem ◽

Ectopic Expression ◽

Cell Fates ◽

Lateral Organs ◽

Expression Studies ◽

Lateral Organ ◽

Yabby Gene ◽

Filamentous Flower

Lateral organs produced by shoot apical and flower meristems exhibit a fundamental abaxial-adaxial asymmetry. We describe three members of the YABBY gene family, FILAMENTOUS FLOWER, YABBY2 and YABBY3, isolated on the basis of homology to CRABS CLAW. Each of these genes is expressed in a polar manner in all lateral organ primordia produced from the apical and flower meristems. The expression of these genes is precisely correlated with abaxial cell fate in mutants in which abaxial cell fates are found ectopically, reduced or eliminated. Ectopic expression of either FILAMENTOUS FLOWER or YABBY3 is sufficient to specify the development of ectopic abaxial tissues in lateral organs. Conversely, loss of polar expression of these two genes results in a loss of polar differentiation of tissues in lateral organs. Taken together, these observations indicate that members of this gene family are responsible for the specification of abaxial cell fate in lateral organs of Arabidopsis. Furthermore, ectopic expression studies suggest that ubiquitous abaxial cell fate and maintenance of a functional apical meristem are incompatible.

Download Full-text