Callose

Callose is a plant polysaccharide. Its production is due to the glucan synthase-like gene (GLS) in various places within a plant. It is produced to act as a temporary cell wall in response to stimuli such as stress or damage.[1] Callose is composed of glucose residues linked together through β-1,3-linkages, and is termed a β-glucan. It is thought to be manufactured at the cell wall by callose synthases and is degraded by β-1,3-glucanases. Callose is very important for the permeability of plasmodesmata (Pd) in plants; the plant’s permeability is regulated by plasmodesmata callose (PDC). PDC is made by callose synthases and broken down by β-1,3-glucanases (BGs). The amount of callose that is built up at the plasmodesmatal neck, which is brought about by the interference of callose synthases (CalSs) and β-1,3-glucanases, determines the conductivity of the plasmodesmata.[2]

Callose
Names
Other names
(1→3)-β-D-Glucan
Identifiers
ChEBI
Properties
(C6H10O5)n
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Formation and function

Callose is laid down at plasmodesmata, at the cell plate during cytokinesis, and during pollen development. Callose is produced in response to wounding, infection by pathogens,[3] aluminium, and abscisic acid. When there is wounding in the plant tissue, it is fixed by the deposition of callose at the plasmodesmata and cell wall; this process happens within minutes after damage. Even though callose is not a constitutional component of the plant’s cell wall, it is related to the plant’s defense mechanism.[4] Deposits often appear on the sieve plates at the end of the growing season.[5] Callose also forms immediately around the developing meiocytes and tetrads of sexually reproducing angiosperms but is not found in related apomictic taxa.[6] Callose deposition at the cell wall has been suggested as an early marker for direct somatic embryogenesis from cortical and epidermal cells of Cichorium hybrids.[7] Temporary callose walls are also thought to be a barrier between a cell and its environment, while the cell is undergoing a genetic programming that allows it to differentiate.[8] This is because, callose walls can be found around nucellar embryos during Nucellar embryony.[9]

See also

References
  1. Hine R, Martin E, eds. (2016). "Callose". A Dictionary of Biology. Oxford University Press.
  2. De Storme N, Geelen D (2014). "Callose homeostasis at plasmodesmata: molecular regulators and developmental relevance". Frontiers in Plant Science. 5: 138. doi:10.3389/fpls.2014.00138. PMC 4001042. PMID 24795733.
  3. Nowicki M, Lichocka M, Nowakowska M, Kłosińska U, Kozik EU (January 2012). "A Simple Dual Stain for Detailed Investigations of Plant-Fungal Pathogen Interactions". Vegetable Crops Research Bulletin. 77 (1). doi:10.2478/v10032-012-0016-z.
  4. Chen XY, Kim JY (June 2009). "Callose synthesis in higher plants". Plant Signaling & Behavior. 4 (6): 489–92. doi:10.4161/psb.4.6.8359. PMC 2688293. PMID 19816126.
  5. Hemsley AR, Bell PR (2000). Green plants : their origin and diversity (2nd ed.). Cambridge: Cambridge University Press. ISBN 978-0-521-64109-8.
  6. Carman JG, Crane CF, Riera-Lizarazu O (1991). "Comparative Histology of Cell Walls during Meiotic and Apomeiotic Megasporogenesis in Two Hexaploid Australasian Elymus Species". Crop Science. 31 (6): 1527. doi:10.2135/cropsci1991.0011183X003100060029x.
  7. Dubois T, Guedira M, Dubois J, Vasseur J (May 1990). "Direct Somatic Embryogenesis in Roots of Cichorium: Is Callose an Early Marker?". Annals of Botany. 65 (5): 539–545. doi:10.1093/oxfordjournals.aob.a087967.
  8. Tucker MR, Paech NA, Willemse MT, Koltunow AM (2001). "Dynamics of callose deposition and ß-1, 3-glucanase expression during reproductive events in sexual and apomictic Hieracium". Planta. 212: 487–498. doi:10.1007/s004250000445.
  9. Gupta P, Shivanna KR, Mohan Ram HY (1996). "Apomixis and polyembryony in the guggul plant, Commiphora wightii". Ann Bot. 78: 67–72. doi:10.1006/anbo.1996.0097.
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