Optimum culture conditions for high frequency plant regeneration from leaf explants of Kalanchoe daigremontiana Hamet &Perrier were established. Shoot regeneration was achieved from leaf explant cultures using MS medium supplemented with indole-3-acetic acid (IAA) and thidiazuron (TDZ) or benzyladenine (BA). Percent regeneration was influenced by plant growth regulators and source of explants. MS medium supplemented with TDZ (1.0 mg/l) and IAA (0.4 mg/l) was the most effective, providing shoot regeneration for 76.7 % of ex vitro leaf explants associated with a high number of shoots per explant (9.5 mean shoots per explant), whereas 100% shoot regeneration associated with 12.4 shoots per explant occurred from in vitro leaf explants on the same medium. Clusters of shoots were multiplied and elongated on MS medium containing several concentrations of BA. MS medium supplemented with 0.25 mg/l BA was proved as the most effective shoot elongation medium. Elongated shoots (2-3 cm) were rooted at 100% on half-strength MS medium. Rooted plantlets were then transferred to potting soil. Regenerated plants were established in the soil with 90% success.

A cytosolic ascorbate peroxidase, hydrogen peroxide-scavenging enzyme, was characterized from Codonopsis lanceolata. The cytosolic ascorbate peroxidase cDNA (CAPX) was 983 nucleotides long and possess an open reading frame of 753 bp with 251 amino acids (MW 27.9 kDa) with pI 5.61. The deduced amino acid sequence of CAPX shows high homology to other known cytosolic APXs (78~83%), but the CAPX was clustered independently from compared ten plant APXs. The CAPX gene was highly expressed in leaf and stem tissues, but not in root. When Codonopsis leaves cut using scalpel were soaked in 1 mM hydorgen peroxide, the expression of CAPX gene was suppressed.

A cinnamoyl CoA reductase (CCR) cDNA (ClCCR) was isolated from tabroot mRNAs of Codonopsis lanceolata by cDNA library construction, and its expression was investigated in relation to abiotic stresses. The ClCCR is 1008 bp in length with an open reading frame (ORF) of 336 amino acids. The deduced amino acid sequence was showed high similarity with cinnamoyl-CoA reductases of P. tremuloides (AAF43141) 87%, F.×aranassa (AAP46143) 83%, L. album (CAD29427) 80%, E. gunnii (CAA66063) 72%, S. tuberosum (AAN71761) 83%. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was revealed that the ClCCR expression was regulated by abiotic stresses.

A thoredoxin (CTRX) gene was cloned and characterized from a full length cDNA library prepared from taproot of three-year old Codonopsis lanceolata. A CTRX was 666 nucleotides long and has an open reading frame of 372 bp with 124 amino acid residues (pI = 4.92). The deduced amino acid sequence of the CTRX matched to the previously reported plant thioredoxin h genes. The deduced amino acid sequence of CTRX exhibited the similarity of 33-67% among previously registered thioredoxin genes. The expression of CTRX in leaves of Codonopsis lanceolata was increased by wounding and 1 mM H2O2, but decreased by 0.1 mM cadmium.

A class I type 2 metallothionein (CMet2) cDNA from taproot of Codonopsis lanceolata was isolated and characterized. A CMet2 cDNA was 572 nucleotides long and had an open reading frame of 234 bp with a deduced amino acid sequence of 78 residues (pI = 4.99). The deduced amino acid sequence of CMet2 matched to the previously reported type 2 metallothionein-like protein genes and showed 74% identity with that of G. max (BAD18377) and C. arietinum (CAA65009). Expression of CMet2 by the RT-PCR was increased at 1 hr after cadmium and hydrogen peroxide treatment, respectively.

A full-length cDNA (PPrx1) encoding peroxidase has been isolated and its nucleotide sequence determined from flower bud in ginseng plant (Panax ginseng). A PPrx1 cDNA is 1192 nucleotides long and has an open reading frame of 1062 bp with a deduced amino acid sequence of 354 residues (pI 7.53). The deduced amino acid sequence of PPrx1 matched to the previously reported peroxidase protein genes. The PPrx1 showed a high similarity with the 64% identity with peroxidase of N. tabacum (AAK52084). In the phylogenetic analysis based on the amino acid residues, the PPrx1 was closer with peroxidase of G. max (AAD37376).

Ribosomal protein complex with ribosomal RNA to form the subunits of the ribosome serve essential functions in protein synthesis. A full-length cDNA (PRPS4) encoding ribosomal protein S4 has been isolated and its nucleotide sequence determined in ginseng plant (Panax ginseng). A PRPS4 cDNA is 1105 nucleotides long and has an open reading frame of 792 bp with a deduced amino acid sequence of 264 residues (pI 10.67). The deduced amino acid sequence of PRPS4 matched to the previously reported ribosomal protein S4 genes. Their degree of amino acid identity ranged from 68 to 92%. Phylogenetic analysis based on the amino acid residues showed that the PRPS4 grouped with ribosomal protein S4 of S. tuberosum (CAA54095).

A cDNA, PSOD1, encoding cytosolic copper/zinc superoxide dismutase (CuZn-SOD) was cloned and characterized from a full length cDNA library prepared from Populus alba×Populus glandulosa cultured in vitro. A PSOD1, is 725 nucleotides long and has an open reading frame of 459 bp with 152 amino acid residues (pI 5.43). The deduced amino acid sequence of PSOD1 perfect matched to the previously reported CuZn-SOD (CAC33845.1). Consensus amino acid residues (His-45, -47, -62, -70, -79, -119) were involved in Cu-, Cu/Zn-, and Zn- binding ligands. The deduced amino acid sequence of PSOD1 exhibited the high level of similarity from 100 to 85% among previously registered SOD genes. The expression of PSOD1 in poplar increased at the 1 mM H2O2 and drought stress during 30 min and 60 min, but the ozone treated poplar increased at 30 min in the early time and then decreased at 60 min.

A type 3 metallothionein cDNA (PMT3a) from ozone-treated Populus alba×Populus glandulosa cDNA library has been isolated and characterized. A PMT3a cDNA is 459 nucleotides long and has an open reading frame of 201 bp with a deduced amino acid sequence of 66 residues (pI 4.94). The deduced amino acid sequence of PMT3a matched to the previously reported metallothionein genes. The deduced amino acid sequence of PMT3a showed the 86% identity with P. balsamifera ×P. deltoides. Expression of PMT3a by the RT-PCR was increased 60 min than 30 min after drought treatment. The ozone treated poplar increased at 30 min in the early time and then decreased at 60 min.

Calmodulin, a Ca2+-binding protein, has no enzyme activity. It combines with Ca2+ and makes variable proteins to an active form. Calmodulin 2 is a ubiquitous protein in plants. To investigate the defense mechanism against various stresses, a clone encoding a calmodulin 2 protein was isolated from a cDNA library prepared from taproot mRNAs of Codonopsis lanceolata. The cDNA, designated CICAM2, is 719 nucleotides long and has an open reading frame of 450 bp with a deduced amino acid sequence of 149 residues. The deduced amino acid sequence of CICAM2 showed a high similarity with calmodulins of P. x hybrida (P27163) 97%, N. tabacum (BAB61908) 97%, S. tuberosum (AAA74405) 96%, Z. mays (CAA74307) 92%, C. richardii (AF510075) 93%, M. truncatula (AAM81203) 91%, and G. max (P62163) 91%. The transcriptional expression of the CICAM2 gene, was gradually increased by the CaCl2 treatment. Whereas its expression And it was gradually decreased in the cold stress treatment.ent.

To investigate the defense mechanism against the abiotic stress, a cDNA clone encoding a CuZn superoxide dismutase (CuZnSOD) protein was isolated from a cDNA library prepared from tabroot mRNAs of Codonopsis lanceolata. The eDNA, designated ClSODCc, is 799 nucleotides long and has an open reading frame of 459 bp with a deduced amino acid sequence of 152 residues. The deduced amino acid sequence of ClSODCc matched to the previously reported CuZnSODs. Consensus amino acid residues (His-45, -47, -62, -70, -79, -119 and Asp-82) were involved in Cu-, Cu/Zn-, and Zn- binding ligands. The deduced amino acid sequence of ClSODCc showed high homologies (82％-86％) regardless of species. Expression of ClSODCc by oxidative stress was increased up to 1 h after treatment and declined gradually. Much earlier and stronger expression of ClSODCc was observed in the cold stress treatment.

Hairy roots were induced from Korean ginseng (Panax ginseng C. A. Meyer) root explants and studied for their gene expression. A total of 3,000 ESTs (expressed sequence tags) from ginseng hairy root were determined and about 2,700 ESTs have a length of readable sequence, which result in 1,352 unique ESTs sequences. The 879 ESTs showed significant similarities to known nucleotide or amino acid sequences in other plant species, which were divided into eleven categories depending upon gene function. The remaining 473 sequences showed no significant matches, which are likely to be transcripts or to be matched to other organisms. The results indicated that the analysis of the ginseng hairy root ESTs by partial sequencing of random cDNA clones may be an efficient approach to isolate genes that are functional in ginseng root in a large scale. Our extensive EST analysis of genes expressed in ginseng hairy root not only contributes to the understanding of the dynamics of genome expression patterns in root organ but also adds data to the repertoire of all genomic genes.

The concerns on the crop damage by ultraviolet (UV) radiations is increasing owing to the decrease of their absorbing stratospheric ozone in the tropospheric. Cultivar differences on early growth of UV radiation among five Korean rice cultivars, four japonica types and one Tongil type (indica-japonica cross hybrid), were studied. Pot-seeded rice plants were grown under four different radiation conditions, i.e., visible radiation only, visible radiation with supplemented with high or low dose of UV-B (280~320 nm in wavelength) and UV-C (less than 280 nm in wavelength). The inhibitory degree on plant height, shoot and root weight and length of leaf blade and leaf sheath were determined at 40 days after seeding. UV-C showed the most severe inhibitory effect on the degree of biomass gain and leaf growth in most cultivars examined, followed by high UV-B and low UV-B. Among the cultivars used, the Kuemobyeo was the most sensitive cultivar and had not repair or showed resistance ability to continued irradiation of UV radiation. However, Janganbyeo and Jaekeon showed different responses that the elongation of leaf blades was promoted on 2nd and 3rd leaves and inhibited on 4th and 5th leaves but this inhibitory degree was reduced on 6 th and 7th leaves. Such tendency on leaf growth means that both cultivars had low sensitivity and most resistant ability to continued irradiation of UV radiation. While Tongil showed different response to enhanced UV radiation, ie., low UV-B promoted leaf growth but the inhibitory was severely increased by continued irradiation of high UV-B and UV-C, which means that Tongil had high threshold of UV radiation for response as an inhibitory light of plant growth. The results of this study indicate that the differences on sensitivity or resistant to the effects of UV radiation were existed among Korean rice cultivars