Chitinase Genes Responsive to Cold Encode Antifreeze Proteins in Winter Cereals

• Published in: Plant physiology (Bethesda) Vol. 124; no. 3; pp. 1251 - 1263
• Main Authors: Sansun Yeh, Moffatt, Barbara A., Griffith, Marilyn, Fei Xiong, Daniel S. C. Yang, Steven B. Wiseman, Sarhan, Fathey, Danyluk, Jean, Yi Qi Xue, Hew, Choy L., Amanda Doherty-Kirby, Gilles Lajoie
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01-11-2000; American Society of Plant Biologists
• Subjects: Acclimatization; Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Amino Acid Sequence; Amino acids; Antifreeze proteins; Antifreeze Proteins - genetics; Antifreeze Proteins - isolation & purification; Antifreeze Proteins - metabolism; Antifreezes; Base Sequence; Biological and medical sciences; Blotting, Southern; Chitinases - genetics; Chitinases - isolation & purification; Chitinases - metabolism; Chromosomes; Cold Temperature; Complementary DNA; DNA, Complementary - isolation & purification; Drought; E coli; Environmental Stress and Adaptation; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; Genes; Genetics and breeding of economic plants; Genome, Plant; Ice; Leaves; Molecular Sequence Data; Plants; RNA, Messenger - analysis; Rye; Secale - genetics; Secale - metabolism; Sequence Alignment; Sequence Analysis, DNA; Triticum - genetics; Triticum - metabolism; Varietal selection. Specialized plant breeding, plant breeding aims; Genetic mapping; Chitinase; Monocotyledones; Secale cereale; Enzyme; Cold resistance; Environmental factor; Cereal crop; Posttranslational modification; Gramineae; Glycosidases; Angiospermae; Hydrolases; Multigene family; Spermatophyta; Biological accumulation; O-Glycosidases; Antifreeze protein; Aminoacid sequence; Adaptation
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.124.3.1251

Antifreeze proteins similar to two different chitinases accumulate during cold acclimation in winter rye (Secale cereale). To determine whether these cold-responsive chitinases require post-translational modification to bind to ice, cDNAs coding for two different full-length chitinases were isolated from a cDNA library produced from cold-acclimated winter rye leaves. CHT9 is a 1,193-bp clone that encodes a 31.7-kD class I chitinase and CHT46 is a 998-bp clone that codes for a 24.8-kD class II chitinase. Chitinase-antifreeze proteins purified from the plant were similar in mass to the predicted mature products of CHT9 and CHT46, thus indicating that there was little chemical modification of the amino acid sequences in planta. To confirm these results, the mature sequences of CHT9 and CHT46 were expressed in Escherichia coli and the products of both cDNAs modified the growth of ice. Transcripts of both genes accumulated late in cold acclimation in winter rye. Southern analysis of winter rye genomic DNA indicated the presence of a small gene family homologous to CHT46. In hexaploid wheat, CHT46 homologs mapped to the homeologous group 1 chromosomes and were expressed in response to cold and drought. We conclude that two novel cold-responsive genes encoding chitinases with ice-binding activity may have arisen in winter rye and other cereals through gene duplication.