Dehydrin

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Dehydrin
Identifiers
Symbol Dehydrin
Pfam PF00257
InterPro IPR000167
PROSITE PS00315

Dehydrin (DHN) is a multi-family of proteins present in plants that is produced in response to cold and drought stress.[1] DHNs are hydrophilic and reliably thermostable. They are stress proteins with a high number of charged amino acids that belong to the Group II Late Embryogenesis Abundant (LEA) family”.[2] DHNs are primarily found in the cytoplasm and nucleus but more recently, they have been found in other organelles, like mitochondria and chloroplasts.[3][4] DHNs are characterized by the presence of Glycine and other polar amino acids.[5] All DHNs contain at least one copy of a consensus 15-amino acid sequence. The “K segment". "This segment, also known as the K-segment, has the sequence EKKGIMDKIKEKLPG. However, an inspection of a range of other reported dehydrin sequences shows that its conservation is not absolute." [6]

Dehydration-induced proteins in plants were first observed in 1989, in a comparison of barley and corn cDNA from plants under drought conditions.[7] The protein has since been referred to as dehydrin and has been the identified as the genetic basis of drought tolerance in plants. However, the first direct genetic evidence of dehydrin playing a role in cellular protection during osmotic shock was not observed until 2005, in the moss, Physcomitrella patens. In order to show a direct correlation between DHN and stress recovery, a knockout gene was created, which interfered with DHNA’s functionality. After being placed in an environment with salt and osmotic stress and then later being returned to a standard growth medium, the P. patens wildtype was able to recover to 94% of its fresh weight while the P. patens mutant only reached 39% of its fresh weight. This study also concludes that DHN production allows plants to function in high salt concentrations.[8] Another study found evidence of DHN’s impact in drought-stress recovery by showing that transcription levels of a DHN increased in a drought-tolerant pine, Pinus pinaster, when placed in a drought treatment. However, transcription levels of a DHN decreased in the same drought treatment in a drought-sensitive P. pinaster. Drought-tolerance is a complex trait, thus that it cannot be genetically analyzed as a single gene trait.[9] The exact mechanism of drought tolerance is yet to be determined and is still being researched. One chemical mechanism related to DHN production is the presence of the phytohormone ABA. One common response to environmental stresses is process known as cellular dehydration. Cellular dehydration induces biosynthesis of abscisic acid (ABA), which is known to react as a stress hormone because of its accumulation in the plant under water stress conditions. ABA also participates in stress signal transduction pathways ABA has been shown to increase the production of DHN, which provides more evidence of a link between DHN and drought tolerance.[10]

There are other proteins in the cell that play a similar role in the recovery of drought treated plants. These proteins are considered dehydrin-like or dehydrin-related. They are poorly defined, in that these dehydrin-like proteins are similar to DHNs, but are unfit to be classified as DHNs for varying reasons.[11] They are found to be similar in that they respond to some or all of the same environmental stresses that induce DHN production. In a particular study dehydrin-like proteins found in the mitochondria were upregulated in drought and cold treatments of cereals.[12]

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References[edit]

  1. ^ Puhakainen T, Hess MW, Mäkelä P, Svensson J, Heino P, Palva ET (March 2004). "Overexpression of multiple dehydrin genes enhances tolerance to freezing stress in Arabidopsis". Plant Molecular Biology. 54 (5): 743–53. doi:10.1023/B:PLAN.0000040903.66496.a4. PMID 15356392. 
  2. ^ Yang Y, He M, Zhu Z, Li S, Xu Y, Zhang C, Singer S, Wang Y (2012). "Identification of the dehydrin gene family from grapevine species and analysis of their responsiveness of various forms of abiotic and biotic stress". BMC Plant Biology. 54 (5): 743–53. doi:10.1186/1471-2229-12-140. 
  3. ^ Rorat T (January 2006). "Plant dehydrins—tissue location, structure and function". Cell and Molecular Biology Letters. 11 (4): 536–56. doi:10.2478/s11658-006-0044-0. PMID 16983453. 
  4. ^ Saavedra L, Svensson J, Carballo V, Izmendi D, Welin B, Vidal S (January 2006). "A dehydrin gene in Physcomitrella patens is required for salt and osmotic stress tolerance". The Plant Journal. 45 (2): 237–49. doi:10.1111/j.1365-313X.2005.02603.x. PMID 16367967. 
  5. ^ Chang-Cai Liu (2012). "Genome-wide Identification and Charactereization of a Dehydrin Gene Family in Poplar (Populis trichocarpa).". Plant Molecular Biology Reporter. 30 (4): 848–59. doi:10.1007/s11105-011-0395-1. 
  6. ^ Graether SP, Boddington KF (2014). "Disorder and function: a review of the dehydrin protein family". Frontiers in Plant Science. 5: 576. doi:10.3389/fpls.2014.00576. 
  7. ^ Close TJ, Kortt AA, Chandler PM (July 1989). "A cDNA-based comparison of dehydration-induced proteins (dehydrins) in barley and corn". Plant Molecular Biology. 13 (1): 95–108. doi:10.1007/bf00027338. PMID 2562763. 
  8. ^ Saavedra L, Svensson J, Carballo V, Izmendi D, Welin B, Vidal S (January 2006). "A dehydrin gene in Physcomitrella patens is required for salt and osmotic stress tolerance". The Plant Journal. 45 (2): 237–49. doi:10.1111/j.1365-313X.2005.02603.x. PMID 16367967. 
  9. ^ Velasco-Conde T, Yakovlev I, Majada J, Aranda I, Johnsen O (2012). "Dehydrins in maritime pine (Pinus pinaster) and their expression related to drought stress response". Tree Genetics and Genomes. 8 (5): 957–73. doi:10.1007/s11295-012-0476-9. 
  10. ^ Borovskii G, Stupnikova I, Antipina A, Vladimirova S, Voinikov V (2002). "Accumulation of dehydrin-like proteins in the mitochondria of cereals in response to cold, freezing, drought and ABA treatment". BMC Plant Biology. 2 (5). doi:10.1186/1471-2229-2-5. 
  11. ^ Rurek M. "Diverse accumulation of several dehydrin-like proteins in cauliflower (Brassica oleracea var. botrytis), Arabidopsis thaliana and yellow lupin (Lupinus luteus) mitochondria under cold and heat stress". BMC Plant Biology. 10 (181): 309–16. doi:10.1186/1471-2229-10-181. 
  12. ^ Borovskii G, Stupnikova I, Antipina A, Vladimirova S, Voinikov V (2002). "Accumulation of dehydrin-like proteins in the mitochondria of cereals in response to cold, freezing, drought and ABA treatment". BMC Plant Biology. 2 (5). doi:10.1186/1471-2229-2-5. 

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