Abstract
Xylem ray parenchyma cells (XRPCs) of Larix kaempferi respond to subfreezing temperatures by deep supercooling in winter. We carried out differential display to isolate genes expressed in association with increase in the magnitude of deep supercooling ability in XRPCs of L. kaempferi, and identified ten genes preferentially expressed during winter seasons. These genes encoded proteins with sequence similarity to NBS/LRR protein (WXL1), organic anion transporter (WXL2), H-pyrophosphatase (WXL3), aminoalcoholphosphotransferase (WXL4), flavonol 3-O-glucosyltransferase (WXL5), histone H2A (WXL6), LRR-containing F-box protein (WXL7), reverse transcriprase (WXL8), a protein similar to Arabidopsis protein T20 L15, 20 (WXL9) and an unknown protein (WXL10). These genes were differentially expressed during fall and winter seasons. Expression of transcripts of WXL4 and 9 increased from October, while that of WXL1, 2, 3, 5, 6, 7, 8 and 10 dramatically increased in November. Transcripts of WXL3 and 9 were similarly expressed in xylem and cortex tissues, while those of WXL1, 2, 4, 5, 6, 7, 8 and 10 were preferentially expressed in xylem tissue.
