scholarly journals HORTICULTURAL CHARACTERISTICS OF TRANSGENIC TOBACCO EXPRESSING THE ROL C GENE FROM AGROBACTERIUM RHIZOGENES

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 621a-621
Author(s):  
R. Scorza ◽  
T.W. Zimmerman ◽  
J.M. Cordts ◽  
K.J. Footen ◽  
M. Ravelonandro

Tobacco (Nicotiana tabacum cv Wisconsin 38) leaf discs were transformed with the disarmed Agrobacterium tumefaciens strain EHA101 carrying the Rol C gene from A. rhizogenes (Oono et al., Jpn. J. Genet. 62:501-505, 1987), NPT II and GUS. Shoots that regenerated on kanamycin-containing medium were confirmed transgenic through GUS assays, Southern analyses and transmission of foreign genes through the sexual cycle. Transgenic plants were as short as half the height of control plants, earlier flowering by up to 35 days, had smaller leaves, smaller seed capsules, fewer seeds, smaller flowers and reduced pollen viability. The number of seed capsules, leaf number and root density were similar between transgenic and control plants. Transgenic clones varied in the expression of the Rol C gene and transgenic plants similar or only slightly different from controls were identified. Transformation with the Rol C gene presents a potentially useful method of genetically modifying horticultural crops, particularly for flowering date, height, and leaf and flower size.

1994 ◽  
Vol 119 (5) ◽  
pp. 1091-1098 ◽  
Author(s):  
R. Scorza ◽  
T.W. Zimmerman ◽  
J.M. Cordts ◽  
K.J. Footen ◽  
M. Ravelonandro

`Wisconsin 38' tobacco (Nicotiana tabacum L.) leaf discs were transformed with the disarmed Agrobacterium tumefaciens strain EHA101 carrying the rolC gene from A. rhizogenes (Oono et al., 1987) and NPT II and GUS genes. Shoots that regenerated on kanamycin-containing medium were confirmed as transgenic through GUS assays, polymerase chain reaction (PCR), Southern blot analyses, and transmission of the foreign genes through the sexual cycle. Transgenic plants were as short as half the height of control plants; were earlier flowering by up to 35 days; and had smaller leaves, shorter internodes, smaller seed capsules, fewer seeds, smaller flowers, and reduced pollen viability. The number of seed capsules, leaf number, and specific root length were similar between transgenic and control plants. Transgenic clones varied in the expression of the rolC-induced growth alterations as did the first generation of seedlings from these clones. Such differences suggested the potential for selecting for different levels of expression. Transformation with the rolC gene presents a potentially useful method of genetically modifying horticultural crops, particularly for flowering date, height, and leaf and flower size. Chemical names used: neomycin phosphotransferase (NPTII), β-glucuronidase (GUS).


HortScience ◽  
1995 ◽  
Vol 30 (3) ◽  
pp. 435f-435 ◽  
Author(s):  
Marceline Egnin ◽  
C.S. Prakash

This study aimed to optimize factors for the efficient delivery of foreign genes into sweetpotato using Agrobacterium tumefaciens and develop transgenic plants. Disarmed Agrobacterium C58 carrying a binary vector pBI 121C2H with gusA, nptll, and the nutritional protein asp-l genes was used to cocultivate (4 days) petiole explants of the sweetpotato genotype P1318846-3. Pre-incubation of petioles for 3 days on MS medium with 2,4-D (0.2 mg·liter–1) before infection resulted in higher transformation. Putative transgenic shoots were obtained by transfer of petioles to MS medium with TDZ (0.2 mg·liter–1) and kanamycin (80 to 140 mg·liter–1). The PCR amplification of gusA, nptll, and asp-1 genes in the 37 putative transgenic shoots showed that six plants contained the three genes. However, none of these plants showed histochemical expression of the gusA gene. The introduced gene may have been methylated resulting in the lack of its expression. DNA blot hybridization studies are underway to verify the presence and integration of the transgenes.


Author(s):  
Patrick S. Michael

Many sweet potato plants have been successfully transformed but the transgenic plants regenerated, however, have been limited to a few genotypes. Reported in this paper is a procedure in which several explants of three sweet potato genotypes from Papua New Guinea (PNG) were used to transform and regenerate transgenic plants. To achieve stable transformation, an efficient shoot regeneration system for different explants was developed. The shoot regeneration protocol developed enabled for a reproducible stable transformation mediated by Agrobacterium tumefaciens strain 1065. The plasmid pVDH65 contains the npt II gene for kanamycin (km) resistance, hpt gene for hygromycin resistance and Gus-intron reporter gene (GUS) for β-glucuronidase. Explants inoculated with the bacterial strain were co-cultured for 3, 5 and 7 days (d) in the dark on Murashige and Skoog (MS) medium without growth hormones. After co-cultivation, the explants were washed in liquid MS medium containing 500 mg L-1 cefotaxime, rinsed in sterile, deionised water for 10 mins and cultured on km selection medium containing 100 mg L-1 km followed by transfer of explants to 125 mg L-1 km after 14 d of culture. The km-resistant shoots selected on the former km concentration were transferred to the latter for double selection. Km-resistant shoots obtained at 125 mg L-1 were rooted on MS based medium also containing 0.008 mg L-1 IAA, 0.03 mg L-1 kinetin and 0.001 mg L-1 folic acid. This double selection method led to effective elimination of escapes (up to 75%) and successful recovery of transgenic plants from stem explants at more than 25%, leaf discs 10% and petioles 13.3% of each sweet potato cultivar. Polymerase chain reaction (PCR) analysis of the three km-resistant and GUS-positive plants revealed the presence of the expected fragment for npt II. This is the first report of successfully transforming sweet potato plants with bacterial strain 1065 and selection of transgenic plants at km concentrations higher than 100 mg L-1.


2011 ◽  
Vol 33 (12) ◽  
pp. 1327-1334 ◽  
Author(s):  
Lin YANG ◽  
Feng-Ling FU ◽  
Wan-Chen LI

1997 ◽  
Vol 325 (2) ◽  
pp. 331-337 ◽  
Author(s):  
Daniel BURTIN ◽  
Anthony J. MICHAEL

The activity of arginine decarboxylase (ADC), a key enzyme in plant polyamine biosynthesis, was manipulated in two generations of transgenic tobacco plants. Second-generation transgenic plants overexpressing an oat ADC cDNA contained high levels of oat ADC transcript relative to tobacco ADC, possessed elevated ADC enzyme activity and accumulated 10–20-fold more agmatine, the direct product of ADC. In the presence of high levels of the precursor agmatine, no increase in the levels of the polyamines putrescine, spermidine and spermine was detected in the transgenic plants. Similarly, the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase were unchanged. No diversion of polyamine metabolism into the hydroxycinnamic acid–polyamine conjugate pool or into the tobacco alkaloid nicotine was detected. Activity of the catabolic enzyme diamine oxidase was the same in transgenic and control plants. The elevated ADC activity and agmatine production were subjected to a metabolic/physical block preventing increased, i.e. deregulated, polyamine accumulation. Overaccumulation of agmatine in the transgenic plants did not affect morphological development.


Author(s):  
Ai-Hua Wang ◽  
Lan Yang ◽  
Xin-Zhuan Yao ◽  
Xiao-Peng Wen

AbstractPhosphoethanolamine N-methyltransferase (PEAMTase) catalyzes the methylation of phosphoethanolamine to produce phosphocholine and plays an important role in the abiotic stress response. Although the PEAMT genes has been isolated from many species other than pitaya, its role in the drought stress response has not yet been fully elucidated. In the present study, we isolated a 1485 bp cDNA fragment of HpPEAMT from pitaya (Hylocereus polyrhizus). Phylogenetic analysis showed that, during its evolution, HpPEAMT has shown a high degree of amino acid sequence similarity with the orthologous genes in Chenopodiaceae species. To further investigate the function of HpPEAMT, we generated transgenic tobacco plants overexpressing HpPEAMT, and the transgenic plants accumulated significantly more glycine betaine (GB) than did the wild type (WT). Drought tolerance trials indicated that, compared with those of the wild-type (WT) plants, the roots of the transgenic plants showed higher drought tolerance ability and exhibited improved drought tolerance. Further analysis revealed that overexpression of HpPEAM in Nicotiana tabacum resulted in upregulation of transcript levels of GB biosynthesis-related genes (NiBADH, NiCMO and NiSDC) in the leaves. Furthermore, compared with the wild-type plants, the transgenic tobacco plants displayed a significantly lower malondialdehyde (MDA) accumulation and higher activities of the superoxide dismutase (SOD) and peroxidase (POD) antioxidant enzymes under drought stress. Taken together, our results suggested that HpPEAMT enhanced the drought tolerance of transgenic tobacco.


2009 ◽  
Vol 191 (7) ◽  
pp. 2033-2041 ◽  
Author(s):  
Meriyem Aktas ◽  
Franz Narberhaus

ABSTRACT Agrobacterium tumefaciens requires phosphatidylcholine (PC) in its membranes for plant infection. The phospholipid N-methyltransferase PmtA catalyzes all three transmethylation reactions of phosphatidylethanolamine (PE) to PC via the intermediates monomethylphosphatidylethanolamine (MMPE) and dimethylphosphatidylethanolamine (DMPE). The enzyme uses S-adenosylmethionine (SAM) as the methyl donor, converting it to S-adenosylhomocysteine (SAH). Little is known about the activity of bacterial Pmt enzymes, since PC biosynthesis in prokaryotes is rare. In this article, we present the purification and in vitro characterization of A. tumefaciens PmtA, which is a monomeric protein. It binds to PE, the intermediates MMPE and DMPE, the end product PC, and phosphatidylglycerol (PG) and phosphatidylinositol. Binding of the phospholipid substrates precedes binding of SAM. We used a coupled in vitro assay system to demonstrate the enzymatic activity of PmtA and to show that PmtA is inhibited by the end products PC and SAH and the antibiotic sinefungin. The presence of PG stimulates PmtA activity. Our study provides insights into the catalysis and control of a bacterial phospholipid N-methyltransferase.


1997 ◽  
Vol 24 (1) ◽  
pp. 97 ◽  
Author(s):  
K. Kazan ◽  
M. D. Curtis ◽  
K. C. Goulter ◽  
J. M. Manners

Double haploid (DH) genotypes of canola (Brassica napus L.) have a high level of genetic uniformity but have not been previously tested for genetic transformation. Transgenic plants from three of four DH genotypes derived from cv. Westar were obtained by inoculation of either hypocotyl segments or root explants with Agrobacterium tumefaciens. For hypocotyl transformation, A. tumefaciens strain LBA4404 containing a binary plasmid with the neomycin phosphotransferase gene (nptII) and a CaMV 35S-peroxidase gene cassette was co-cultivated with hypocotyl segments taken from the 5–6-day-old seedlings. Transformation frequencies for hypocotyl explants of two DH genotypes were 0.3–3%. Direct evidence for genetic transformation of hypocotyl explants was obtained through molecular hybridisation analysis. Using this protocol, mature transformed plants were obtained within 4–6 months of co-cultivation. A method of root transformation was successfully modified for one DH genotype of canola and transgenic plants were obtained at a frequency of 2%. Using this protocol, a peroxidase gene promoter–GUS fusion construct was introduced into a DH genotype. Tissue specific GUS expression driven by the peroxidase gene promoter in transgenic plants was analysed by GUS staining. Transformation systems for double haploid canola lines will permit the assessment of introduced genes for their effect on agronomic and physiological traits.


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