Expression of a putative laccase gene, ZmLAC1, in maize primary roots under stress.
Laccases are multi-copper-containing glycoproteins and comprise a multi-gene family in plants. However, their physiological functions are still not well understood. We obtained sequence information for a putative laccase gene, ZmLAC1, from maize and studied ZmLAC1 expression in detail. The deduced ZmLAC1 protein was 70% identical to LpLAC5-4, a laccase from ryegrass. ZmLAC1 was expressed in leaves, stems and roots of maize seedlings. In unstressed maize primary roots, a higher ZmLAC1 transcript level was located in the basal region where cell elongation had ceased compared to the apical 5 mm of the roots where cells were rapidly dividing and elongating. A treatment with 300 mM NaCl resulted in a shortened root elongation zone (< 2 mm) and swelling in the apical 5 mm. Associated with the morphological change, the transcript level of ZmLACl was enhanced in the apical 5 mm, reaching a level similar to that in the basal region. Other abiotic stresses tested--such as 28.5% polyethylene glycol (PEG), which caused an inhibition of root elongation comparable to 300 mM NaCl--did not affect ZmLAC1 transcript level. Potential roles of ZmLAC1 in the roots responding to NaCl or other high concentration of salts are discussed.
Liang
Mingxiang
M
Department of Plants, Soils and Biometeorology, Utah State University, Logan, UT 84322, USA.
Haroldsen
Victor
V
Cai
Xiaoning
X
Wu
Yajun
Y
D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers; D020224:Expressed Sequence Tags; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D042845:Laccase / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012965:Sodium Chloride / Q000494:pharmacology; D014158:Transcription, Genetic; D003313:Zea mays / Q000235:genetics*
D017931:DNA Primers; D012965:Sodium Chloride; D042845:Laccase