Expression of antifreeze proteins in transgenic plants.
The quality of frozen fruits and vegetables can be compromised by the damaging effects of ice crystal growth within the frozen tissue. Antifreeze proteins in the blood of some polar fishes have been shown to inhibit ice recrystallization at low concentrations. In order to determine whether expression of genes of this type confers improved freezing properties to plant tissue, we have produced transgenic tobacco and tomato plants which express genes encoding antifreeze proteins. The afa3 antifreeze gene was expressed at high steady-state mRNA levels in leaves from transformed plants, but we did not detect inhibition of ice recrystallization in tissue extracts. However, both mRNA and fusion proteins were detectable in transgenic tomato tissue containing a chimeric gene encoding a fusion protein truncated staphylococcal protein A and antifreeze protein. Furthermore, ice recrystallization inhibition was detected in this transgenic tissue.
Hightower
R
R
DNA Plant Technology Corporation, Oakland, CA 94608.
Baden
C
C
Penzes
E
E
Lund
P
P
Dunsmuir
P
P
D000595:Amino Acid Sequence; D000818:Animals; D021301:Antifreeze Proteins; D002678:Chimera; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D005399:Fishes; D005615:Freezing; D006023:Glycoproteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D007053:Ice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D015183:Restriction Mapping; D014026:Nicotiana / Q000235:genetics*; D014158:Transcription, Genetic
D021301:Antifreeze Proteins; D006023:Glycoproteins; D007053:Ice; D011994:Recombinant Proteins