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Scientia Silvae Sinicae ›› 2013, Vol. 49 ›› Issue (12): 64-72.doi: 10.11707/j.1001-7488.20131210

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Isolation and Expression of ClPAL Genes in Chinese Fir (Cunninghamia lanceolata)

Xu Lili, Tong Zaikang, Lin Erpei, Huang Huahong   

  1. A Nurturing Station for the State Key Laboratory of Subtropical Silviculture Zhejiang Agricultural and Forestry University Lin'an 311300
  • Received:2013-02-05 Revised:2013-09-11 Online:2013-12-25 Published:2014-01-01

Abstract:

In this study, three full-length cDNAs encoding phenylalanine ammonia lyase (PAL) were isolated from Chinese Fir (Cunninghamia lanceolata) using RACE. They encode 709, 710 and 709 amino acids, respectively, and their sequence lengths are 2 455, 2 418 and 2 689 bp, respectively. The amino acid sequences contain two functional domains of PAL-HAL and PAL, and the enzyme active site (GTITASGDLVPLSYIA). The expression analysis showed that the three ClPALs differentially expressed in different organs. The expression level of ClPAL1 in lignified stem was higher than that in needle, male cone, root and non-lignified stem, and ClPAL3 was mainly expressed in lignified stem. Both genes were predominantly expressed in xylem, and their expression levels in intermediate wood were over 20 times higher than that in sapwood. ClPAL2 exhibited the high transcript abundance in phloem-enriched needles and bark. IAA, GA3 and BR can promote the differentiation of xylem cells, and thus they should directly or indirectly associate with lignin biosynthesis. After application of the three hormones, ClPAL1 and ClPAL3 were induced to different extents, and changes in the expressions were relatively more significant with IAA and BR, indicating that ClPAL1 and ClPAL3 were likely to play important roles in lignin biosynthesis of Chinese Fir wood tissue. During the compression wood formation, the expression level of ClPAL1 in the compression area of xylem showed decreased then increased, and reached to 1.4 times of the control level after 10 days bending treatment. Its expression levels in the opposite area of the compressed zone were lower than that of the control. The ClPAL2 expression was up-regulated in the compression wood, and its value in the opposite wood area was obviously higher than that of the control after 10 days bending. The expression changes of ClPAL3 were not significant compared with the control. In addition, the expression level of the ClPAL2 in intermediate wood was higher than that in sapwood. It deserves further study whether this gene would participate in the formation of the heartwood color.

Key words: Cunninghamia lanceolata, PAL gene, gene cloning, gene expression, wood formation

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