To investigate how roots respond to directional cues, we characterized a T-DNA-tagged Arabidopsis mutant named sku5 in which the roots skewed and looped away from the normal downward direction of growth on inclined agar surfaces. sku5 roots and etiolated hypocotyls were slightly shorter than normal and exhibited a counterclockwise (left-handed) axial rotation bias. The surface-dependent skewing phenotype disappeared when the roots penetrated the agar surface, but the axial rotation defect persisted, revealing that these two directional growth processes are separable. The SKU5 gene belongs to a 19-member gene family designated SKS (SKU5 Similar) that is related structurally to the multiple-copper oxidases ascorbate oxidase and laccase. However, the SKS proteins lack several of the conserved copper binding motifs characteristic of copper oxidases, and no enzymatic function could be assigned to the SKU5 protein. Analysis of plants expressing SKU5 reporter constructs and protein gel blot analysis showed that SKU5 was expressed most strongly in expanding tissues. SKU5 was glycosylated and modified by glycosyl phosphatidylinositol and localized to both the plasma membrane and the cell wall. Our observations suggest that SKU5 affects two directional growth processes, possibly by participating in cell wall expansion.
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http://dx.doi.org/10.1105/tpc.002360 | DOI Listing |
Plant Physiol
July 2023
FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
The primary cell wall is a fundamental plant constituent that is flexible but sufficiently rigid to support the plant cell shape. Although many studies have demonstrated that reactive oxygen species (ROS) serve as important signaling messengers to modify the cell wall structure and affect cellular growth, the regulatory mechanism underlying the spatial-temporal regulation of ROS activity for cell wall maintenance remains largely unclear. Here, we demonstrate the role of the Arabidopsis (Arabidopsis thaliana) multicopper oxidase-like protein skewed 5 (SKU5) and its homolog SKU5-similar 1 (SKS1) in root cell wall formation through modulating ROS homeostasis.
View Article and Find Full Text PDFJ Plant Physiol
January 2023
Key Laboratory of Xinjiang Phytomedicine Resource and Utilization of Ministry of Education, Key Laboratory of Oasis Town and Mountain-basin System Ecology of Xinjiang Production and Construction Corps, College of Life Sciences, Shihezi University, Shihezi, 832003, China. Electronic address:
Ascorbate oxidase (AO) and skewed5 (SKU5)-similar (SKS) proteins belong to the multicopper oxidase (MCO) family and play important roles in plants in response to environmental stress via modulation of oxidoreduction homeostasis. Currently, reports on the response of Gossypium barbadense MCO to Verticillium wilt (VW) caused by Verticillium dahliae are still limited. Herein, RNA sequencing of two G.
View Article and Find Full Text PDFCurr Biol
May 2022
Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent 9052, Belgium; Center for Plant Systems Biology, VIB, Ghent 9052, Belgium. Electronic address:
Glycosylphosphatidylinositol-anchored proteins (GPI-APs) are tethered to the outer leaflet of the plasma membrane where they function as key regulators of a plethora of biological processes in eukaryotes. Self-incompatibility (SI) plays a pivotal role regulating fertilization in higher plants through recognition and rejection of "self" pollen. Here, we used Arabidopsis thaliana lines that were engineered to be self-incompatible by expression of Papaver rhoeas SI determinants for an SI suppressor screen.
View Article and Find Full Text PDFPlant J
February 2022
Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Key Laboratory of Molecular and Cellular Biology of Ministry of Education, Collaboration Innovation Center for Cell Signaling, Hebei Normal University, Shijia Zhuang, Hebei, 050024, P.R. China.
Pollen tube integrity, growth and guidance are crucial factors in plant sexual reproduction. Members of the plant Skewed5 (SKU5) Similar (SKS) family show strong similarity to multicopper oxidases (MCOs), but they lack conserved histidines in MCO active sites. The functions of most SKS family members are unknown.
View Article and Find Full Text PDFJ Exp Bot
January 2022
National Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, China271018.
Pollen tube growth and penetration in female tissues are essential for the transfer of sperm to the embryo sac during plant pollination. Despite its importance during pollination, little is known about the mechanisms that mediate pollen tube growth in female tissues. In this study, we identified an Arabidopsis thaliana pollen/pollen tube-specific gene, SKU5-SIMILAR 13 (SKS13), which was critical for the growth of pollen tubes in the transmitting tract.
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