Abstract：Dehydrins (DHNs), known as a group of late embryogenesis abundant proteins (LEA) in plants, are related to various environment stresses. In this study, CsDHN (GenBank accession No. FJ436978), a full length cDNA of DHN in tea plant(Camellia sinensis) was amplified via rapid-amplification of cDNA ends (RACE) technology. It was shown that the full-length cDNA was 960 bp, encoding 201 amino acids by sequence analysis. The deduced molecular weight of DHN protein was 21 kD, together with isoelectric point 8.3, which belonged to the Y3SK2 type of dehydrins. There were 2 exons and 1 intron in CsDHN. The bioinformatics prediction revealed that CsDHN located in the cytoplasm with no signal peptide or transmembrane domain. It was predicted to show strong hydrophilicity. The analysis of characteristic expression showed that CsDHN was up-regulated in tea plant exposed to low temperature, dehydration, abscisic acid(ABA) treatment and salt stress. The expression of CsDHN was increased not satisfactorily at 3 and 6 h under low temperature stress at 4 ℃, while the expression level was increased greatly (two times higher than control, P＜0.05) at 12 h. And the highest expression, 4.2-fold than that of control, was found at 18 h treatment, then decreased to its original level as control at 24 h. After the treatment of dehydration, the expression of CsDHN was increased dramatically. The expression level was 7.5-fold than that of control at 3 h and continuously increased to the highest level at 18 h, with the expression level was 93.4-fold (P＜0.05) than that of control. After that, the expression was decreased to some extent, not maintained a high level. In accordance to ABA treatment, the expression amount was markedly increased at 3 h, and reached to its greatest amount at 6 h (4.3-fold than that of control, P＜0.05), then began to decline. A little bit higher than its original level was found at 18 h to 24 h treatment. When treated with the solution of 300 mmol/L NaCl, the expression level of CsDHN was increased all the time till to 24 h, which was 2.5-fold and 17.8-fold than that of the original level at 3 h and 24 h, respectively. In the normal growth conditions, the expression of CsDHN existed in all organs in tea plant, which CsDHN was a constitutive expression gene. While, the expression patterns in all organs were obviously different. The highest expression was found in mature seeds (the expression was 11.2-fold than that of mature leaves); similar expression level were found in bud and leaves. But the expression levels in young stems, flowers and young roots were low with no significance, which were 0.24, 0.26, 0.32 -folds compared with leaves, respectively. This study showed that the CsDHN might participates with the defense against abiotic stress for tea plants and dehydration vitality protection during tea seeds maturation, which provides a certain theory foundation for understanding the molecular mechanism to tea stress resistance.
[1]Dure III L, Crouch M, Harada J, et al. Common amino acid sequence domains among the LEA proteins of higher plants[J].Plant molecular biology, 1989, 12(5):475-486
[2]Welin B V, Olson ?, Nylander M, et al. Characterization and differential expression of dhn/lea/rab-like genes during cold acclimation and drought stress in Arabidopsis thaliana [J].Plant molecular biology, 1994, 26(1):131-144
[3]豆玲, 张林生, 刑东.水分胁迫下小麦叶片类脱水素表达及亚细胞定位[J].农业生物技术学报, 2011, 19(4):642-648
[4]Zhu W N, Zhang L S, Zhang N, et al.The clone of wheat dehydrin-like gene wzy2 and its functional analysis in Pichia pastoris[J].African Journal of Biotechnology, 2012, 11(40): 9549-9558
[5]Choi D W, Zhu B and Close T J.The barley (Hordeum vulgare L.) dehydrin multigene family: sequences, allele types, chromosome assignments, and expression characteristics of 11 Dhn genes of cv Dicktoo[J].Theoretical and Applied Genetics, 1999, 98(8):1234-1247
[6]Yao K, Lockhart K M, and Kalanack J. Cloning of dehydrin coding sequences from Brassica juncea and Brassica napus and their low temperature-inducible expression in germinating seeds[J].Plant Physiology and Biochemistry, 2005, 43(1):83-89
[7]Close T J, Alexander A K and Peter M C. A cDNA-based comparison of dehydration-induced proteins (dehydrins) in barley and corn[J]. [J].Plant molecular biology, 1989, 13(1):95-108
[8]Peng Y, Reyes J L, Wei H, et al.a cold acclimation‐responsive dehydrin from Rhododendron catawbiense rescues enzyme activity from dehydration effects in vitro and enhances freezing tolerance in RcDhn5‐overexpressing Arabidopsis plants [J].Physiologia plantarum, 2008, 134(4):583-597
[9]Ren Y Y, Wang Z L, Kang X Y, et al. Cloning and Expression Analysis of Dehydrin Gene (Phdhn1) in Populus hopeiensis Under Stress[J].Chinese Agricultural Science Bulletin, 2012, 10(0):005-005
[10]Teresa M, Sanchez-Ballesta, Rodrigo M J, et al.Dehydrin from citrus, which confers in vitro dehydration and freezing protection activity, is constitutive and highly expressed in the flavedo of fruit but responsive to cold and water stress in leaves[J].Journal of agricultural and food chemistry, 2004., 52(7):1950-1957
[11]Hara M, Fujinaga M and Kuboi T. Metal binding by citrus dehydrin with histidine-rich domains[J].Journal of Experimental Botany, 2005, 56(420):2695-2703
[12]Xiao H and Nassuth A..Stress-and development-induced expression of spliced and unspliced transcripts from two highly similar dehydrin 1 genes in V. riparia and V. vinifera[J].Plant cell reports, 2006, 25(9): 968-977
[13]胡孝义, 谭晓风, 张党权, 等.1个油茶Y_2SK_2型脱水素的全长cDNA克隆及生理功能的预测[J].林业科学, 2008, 44(10):55-62
[14]韦朝领, 李叶云, 江昌俊.茶树逆境生理及其分子生物学研究进展[J].安徽农业大学学报, 2009, 36 (3):335-339
[15]Allagulova C, F Gimalov, F Shakirova, et al. The plant dehydrins: structure and putative functions[J].Biochemistry, 2003, 68(9):945-951
[16]Rorat T. Plant dehydrins—tissue location, structure and function[J].Cell Mol Biol Lett, 2006, 11(0):536-556
[17]Castonguay Y, Dube MP, Cloutier J, et al. Intron-length polymorphism identifies a Y2K4 dehydrin variant linked to superior freezing tolerance in alfalfa[J].Theoretical and Applied Genetics, 2012, 124(5):809-819
[18]Pedro Perdiguero, M Carmen Barbero, M. Teresa Cervera, et al.. Novel conserved segments are associated with differential expression patterns for Pinaceae dehydrins[J].Planta,, 2012, 236(6):1863-1874
[19]Deng Z X, Pang Y Z, Kong W W, et al. A novel ABA-dependent dehydrin ERD10 gene from Brassica napus[J].DNA Sequence, 2005, 16(1):28-35
[20]Ochoa-Alfaro A E, Rodriguez-Kessler M, Perez-Morales M B, et al.Functional characterization of an acidic SK3 dehydrin isolated from an Opuntia streptacantha cDNA library[J].Planta, 2012, 235(3):565-578
[21]Zhu W, Zhang L, H Zhang Lv H, et al. The dehydrin wzy2 promoter from wheat defines its contribution to stress tolerance[J].Funct Integr Genomics,, 2014, 14(1):111-125
[22]Zhu B, Choi DW, Fenton R, et al.Expression of the barley dehydrin multigene family and the development of freezing tolerance[J]. [J].Mol Gen Genet, 2000, 264(1/2):145-153
[23]Labhilili M, Jourdier P, Gautier MF. Characterization of cDNAs encoding Triticum durum dehydrins and their expression patterns in cultivars that differ in drought tolerance[J].[J].Plant Sci, 1995, 112(2):219-230
[24]Pelah D, Wang WX, Altman A, et al.Differential accumulation of water stress-related proteins, sucrose synthase and soluble sugars in populus species that differ in their water stress response[J].Physiol Plantarum, 1997, 99(1):153-159
[25]张宁, 孙敏善, 刘露露, 等.小麦脱水素基因TaDHN-1的特征及其对非生物胁迫响应[J].中国农业科学, 2013, 46(4):849-858
[26]Choi D W, Close T J.A newly identified barley gene, Dhn12, encoding YSK2 DHN, is located on chromosome 6H and has embryo-specific expression[J].Theor Appl Genet, 2000, 100(8):1274-1278
[27]Han B, Hughes D W, Galau G A, et al. Changes in late-embryogenesis-abundant (LEA) messenger RNAs and dehydrins during maturation and premature drying of Ricinus communisL seeds [J].Planta, 1997, 201(0):27-35
[28]Kleinwachter M, Radwan A, Hara M et al. Dehydrin expression in seeds: an issue of maturation drying[J].Front Plant Sci, 2014, 5(0):402-402
