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Characterization and expression of dehydrins in water‐stressed Sorghum bicolor
Author(s) -
Wood Andrew J.,
Goldsbrough Peter B.
Publication year - 1997
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1997.tb03442.x
Subject(s) - sorghum , biology , transpiration , complementary dna , sorghum bicolor , stomatal conductance , botany , drought tolerance , proline , abscisic acid , horticulture , gene , photosynthesis , amino acid , agronomy , biochemistry
The effect of water deficit was compared between drought‐tolerant (P954035) and drought‐susceptible (P721N) sorghum ( Sorghum bicolor [L.] Moench) genotypes. Gas analysis and leaf water potential (Ψ W ) measurements indicated clear phenotypic differences between the genotypes in response to water deficit. Both genotypes experienced declines in Ψ W , net assimilation rate (A), transpiration rate (E) and stomatal conductance (g s ) during stress. P954035, however, dried more slowly and maintained higher values for A, E and g s relative to P721N. In vivo labeling studies and immunoblot analysis using an anti‐dehydrin antibody identified a protein of M r 21 000 which was induced by water deficit and accumulated to similar levels in both genotypes. The observed molecular changes were essentially identical in both genotypes but differed only in the timing of expression. A sorghum dehydrin cDNA, dhnl , was isolated which encodes a hydrophilic protein of approximately 16.3 kDa with a predicted pl of 10.48. The deduced polypeptide sequence contains two lysine‐rich elements (KKGIMDKIKEKLPG) and shares extensive homology with other dehydrins. DHN 1 mRNA was induced by water deficit in seedlings of both drought‐tolerant and drought‐susceptible sorghum genotypes. Water deficit also induced changes in gene expression in mature preflowering sorghum plants. The anti‐dehydrin antibody detected a protein that accumulated in leaves and roots of stressed plants. The level of DHN 1 mRNA increased in the same tissues, but the abundance of this transcript was much higher in leaves and roots of mature plants than in seedlings.