An abscisic-acid- and salt-stress-responsive rice cDNA from a novel plant gene family.
A novel cDNA clone osr40cl, encoding a abscisic acid (ABA)-responsive 40-kDa protein previously associated with salt tolerance (Moons et al. '1995' Plant Physiol 107: 177-186), was isolated from roots of rice seedlings (Oryza sativa L.). Exogenously applied ABA and salt shock induced a marked increase of the osr40cl transcript level in roots of seedlings whereas constant osr40cl mRNA levels were found in the shoot. The root-specific salinity-induced osr40cl mRNA accumulation was rapid and gradually declined upon prolonged salt shock. Plant growth regulators, signalling the wounding and the pathogen response, did not enhance osr40cl expression, indicating a salt- and osmotic-stress-specific response. The encoded OSR40cl protein was found to be hydrophilic, rich in histidine residues (6%) constituting putative metal-binding domains, and to consist of a duplicated domain of 151 amino acids (75% identical), that can form amphiphilic alpha-helical structures. The gene osr40cl belongs to a multigene family. Two osr40 genes were isolated, osr40g2 and osr40g3, tandemly arranged in an 8-kb region of the rice genome. Antisera raised against a conserved OSR40 peptide recognized different OSR40 proteins that accumulated in roots upon exposure to salt stress. The OSR40 protein family included 29-KDa proteins and two 40-kDa proteins, the latter most probably corresponding to OSR40cl and OSR40g2 with duplicated domain structures. The osr40g3 transcript encoded a single copy of the OSR40 domain and exhibited a shoot-specific expression. Results indicate that OSR40cl plays a role in the adaptive response of roots to an hyper-osmotic environment and belongs to a novel plant protein family that most probably has structural functions.
Moons
A
A
Department of Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), Universiteit Gent, Belgium.
Gielen
J
J
Vandekerckhove
J
J
Van der Straeten
D
D
Gheysen
G
G
Van Montagu
M
M
D000040:Abscisic Acid / Q000494:pharmacology*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018744:DNA, Plant / Q000737:chemistry / Q000378:metabolism*; D017343:Genes, Plant; D008969:Molecular Sequence Data; D005810:Multigene Family; D012275:Oryza / Q000235:genetics* / Q000378:metabolism*; D009994:Osmolar Concentration; D010940:Plant Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D018517:Plant Roots; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
D018076:DNA, Complementary; D018744:DNA, Plant; C107833:OSR40C1 protein, Oryza sativa; D010940:Plant Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012965:Sodium Chloride; D000040:Abscisic Acid