scholarly journals Cortical Microtubule Organization during Petal Morphogenesis in Arabidopsis

2019 ◽  
Vol 20 (19) ◽  
pp. 4913 ◽  
Author(s):  
Yanqiu Yang ◽  
Weihong Huang ◽  
Endian Wu ◽  
Chentao Lin ◽  
Binqing Chen ◽  
...  

Cortical microtubules guide the direction and deposition of cellulose microfibrils to build the cell wall, which in turn influences cell expansion and plant morphogenesis. In the model plant Arabidopsis thaliana (Arabidopsis), petal is a relatively simple organ that contains distinct epidermal cells, such as specialized conical cells in the adaxial epidermis and relatively flat cells with several lobes in the abaxial epidermis. In the past two decades, the Arabidopsis petal has become a model experimental system for studying cell expansion and organ morphogenesis, because petals are dispensable for plant growth and reproduction. Recent advances have expanded the role of microtubule organization in modulating petal anisotropic shape formation and conical cell shaping during petal morphogenesis. Here, we summarize recent studies showing that in Arabidopsis, several genes, such as SPIKE1, Rho of plant (ROP) GTPases, and IPGA1, play critical roles in microtubule organization and cell expansion in the abaxial epidermis during petal morphogenesis. Moreover, we summarize the live-confocal imaging studies of Arabidopsis conical cells in the adaxial epidermis, which have emerged as a new cellular model. We discuss the microtubule organization pattern during conical cell shaping. Finally, we propose future directions regarding the study of petal morphogenesis and conical cell shaping.

2019 ◽  
Vol 70 (19) ◽  
pp. 5231-5243 ◽  
Author(s):  
Yanqiu Yang ◽  
Binqinq Chen ◽  
Xie Dang ◽  
Lilan Zhu ◽  
Jinqiu Rao ◽  
...  

Abstract Unlike animal cells, plant cells do not possess centrosomes that serve as microtubule organizing centers; how microtubule arrays are organized throughout plant morphogenesis remains poorly understood. We report here that Arabidopsis INCREASED PETAL GROWTH ANISOTROPY 1 (IPGA1), a previously uncharacterized microtubule-associated protein, regulates petal growth and shape by affecting cortical microtubule organization. Through a genetic screen, we showed that IPGA1 loss-of-function mutants displayed a phenotype of longer and narrower petals, as well as increased anisotropic cell expansion of the petal epidermis in the late phases of flower development. Map-based cloning studies revealed that IPGA1 encodes a previously uncharacterized protein that colocalizes with and directly binds to microtubules. IPGA1 plays a negative role in the organization of cortical microtubules into parallel arrays oriented perpendicular to the axis of cell elongation, with the ipga1-1 mutant displaying increased microtubule ordering in petal abaxial epidermal cells. The IPGA1 family is conserved among land plants and its homologs may have evolved to regulate microtubule organization. Taken together, our findings identify IPGA1 as a novel microtubule-associated protein and provide significant insights into IPGA1-mediated microtubule organization and petal growth anisotropy.


2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Veronica Giourieva ◽  
Emmanuel Panteris

Abstract Background Cortical microtubules regulate cell expansion by determining cellulose microfibril orientation in the root apex of Arabidopsis thaliana. While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos, mre1, any1, prc1-1 and rsw1, and the Cellulose Synthase Interacting 1 protein (csi1) mutant pom2-4. In addition, various treatments with drugs affecting cell expansion were performed on wild-type roots. Whole mount tubulin immunolabeling was applied in the above roots and observations were performed by confocal microscopy. Results Cortical microtubules in all mutants showed statistically significant increased persistence against anti-microtubule drugs, compared to those of the wild-type. Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. After these treatments, cortical microtubules appeared more resistant to oryzalin, than in the control. Conclusions According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules.


2011 ◽  
Vol 194 (4) ◽  
pp. 631-642 ◽  
Author(s):  
Kaelyn D. Sumigray ◽  
Hsin Chen ◽  
Terry Lechler

Desmosomes are cell–cell adhesion structures that integrate cytoskeletal networks. In addition to binding intermediate filaments, the desmosomal protein desmoplakin (DP) regulates microtubule reorganization in the epidermis. In this paper, we identify a specific subset of centrosomal proteins that are recruited to the cell cortex by DP upon epidermal differentiation. These include Lis1 and Ndel1, which are centrosomal proteins that regulate microtubule organization and anchoring in other cell types. This recruitment was mediated by a region of DP specific to a single isoform, DPI. Furthermore, we demonstrate that the epidermal-specific loss of Lis1 results in dramatic defects in microtubule reorganization. Lis1 ablation also causes desmosomal defects, characterized by decreased levels of desmosomal components, decreased attachment of keratin filaments, and increased turnover of desmosomal proteins at the cell cortex. This contributes to loss of epidermal barrier activity, resulting in completely penetrant perinatal lethality. This work reveals essential desmosome-associated components that control cortical microtubule organization and unexpected roles for centrosomal proteins in epidermal function.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Shogo Takatani ◽  
Shinichiro Ozawa ◽  
Noriyoshi Yagi ◽  
Takashi Hotta ◽  
Takashi Hashimoto ◽  
...  

2009 ◽  
Vol 1 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Rinku Jitendrakumar DESAI ◽  
Vinay Madhukar RAOLE ◽  
Arun Omprakash ARYA

As micromorphological knowledge was not available for Coix aquatica Roxb., the foliar epidermal studies were carried out for Coix lacryma-jobi L. and Coix aquatica Roxb. with the aim of determining the patterns of variation in their epidermal characteristics and assessing their value in species identification. Comparative foliar analysis was carried out by using light microscopy, after following routine scraping method. The characters of diagnostic importance in the identification of C. aquatica are the sparsely distributed prickle hairs with long pointed apex in the abaxial epidermis and dumbbell shaped silica cells in both the epidermises. The diagnostic characters for C. lacryma-jobi are the cross shaped silica cells and dumbbell shaped on the abaxial and adaxial epidermis respectively. The observed differences in certain micromorphological characters helps in identification of presently studied two species of Coix.


1991 ◽  
Vol 4 (2) ◽  
pp. 391
Author(s):  
M Lazarides ◽  
J Lenz ◽  
L Watson

Clausospicula, a new monotypic genus from the Darwin and Gulf District, Northern Territory, Australia, is described and illustrated. Its diagnostic characters include cleistogamous spikelets, reduced panicles, racemes and spikelets, and pedicelled spikelets which are poorly developed and deciduous, or suppressed. Also, the glumes of the bisexual spikelet are awned and slightly keeled or without keels. A prominent feature is the extension of the peduncle into an appendage to which the callus of the bisexual spikelet is attached. The epidermis is notable for its distinct costal and intercostal zones, rectangular intercostal long-cells with tessellated, pitted cell walls, stomata inserted beneath the overlapping interstomatals and arranged in definite rows bordering the costal zones, the presence of macrohairs, narrow microhairs 39–46.5 µm long, silica-celllcork-cell pairs with dumbbell-shaped silica bodies costally and butterfly-shaped silica bodies intercostally. The transverse section shows a distinct midrib with the vascular bundles arranged in a conventional arc abaxially and colourless tissue adaxially, and a symmetrically ordered lamina. The primary vascular bundles are accompanied by sclerenchyma as girders abaxially and adaxially; the adaxial epidermis is extensively bulliform and the abaxial epidermis is of bulliform-like cells.


2009 ◽  
Vol 19 (21) ◽  
pp. 1827-1832 ◽  
Author(s):  
Ying Fu ◽  
Tongda Xu ◽  
Lei Zhu ◽  
Mingzhang Wen ◽  
Zhenbiao Yang

2009 ◽  
Vol 187 (6) ◽  
pp. 831-845 ◽  
Author(s):  
George von Dassow ◽  
Koen J.C. Verbrugghe ◽  
Ann L. Miller ◽  
Jenny R. Sider ◽  
William M. Bement

Animal cells decide where to build the cytokinetic apparatus by sensing the position of the mitotic spindle. Reflecting a long-standing presumption that a furrow-inducing stimulus travels from spindle to cortex via microtubules, debate continues about which microtubules, and in what geometry, are essential for accurate cytokinesis. We used live imaging in urchin and frog embryos to evaluate the relationship between microtubule organization and cytokinetic furrow position. In normal cells, the cytokinetic apparatus forms in a region of lower cortical microtubule density. Remarkably, cells depleted of astral microtubules conduct accurate, complete cytokinesis. Conversely, in anucleate cells, asters alone can support furrow induction without a spindle, but only when sufficiently separated. Ablation of a single centrosome displaces furrows away from the remaining centrosome; ablation of both centrosomes causes broad, inefficient furrowing. We conclude that the asters confer accuracy and precision to a primary furrow-inducing signal that can reach the cell surface from the spindle without transport on microtubules.


2014 ◽  
Vol 9 (6) ◽  
pp. e28737 ◽  
Author(s):  
Emmanuel Panteris ◽  
Ioannis-Dimosthenis S Adamakis ◽  
Gerasimos Daras ◽  
Stamatis Rigas

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