scholarly journals Constitutive Expression of Pea Defense Gene DRR206 Confers Resistance to Blackleg (Leptosphaeria maculans) Disease in Transgenic Canola (Brassica napus)

1999 ◽  
Vol 12 (5) ◽  
pp. 410-418 ◽  
Author(s):  
Yaping Wang ◽  
Goska Nowak ◽  
David Culley ◽  
Lee A. Hadwiger ◽  
Brian Fristensky

To identify genes effective against the blackleg fungus Leptosphaeria maculans (Phoma lingam), we have transformed canola (Brassica napus) with four pea (Pisum sativum) genes under constitutive control by the cauliflower mosaic virus 35S promoter: PR10.1, chitinase, DRR206, and defensin. Transgenic lines containing single-copy T-DNA insertions for each gene were screened for both seedling (cotyledonary) and adult plant resistance. Lines for which pea DRR206 mRNA was expressed showed decreased disease scores, compared with non-expressing transgenic lines. Transgenic plants expressing pea defensin showed a slight enhancement of resistance, while for PR10 and chitinase transgenics there was little or no enhancement of resistance. Resistance to L. maculans cosegregated with DRR206 transgenes. Extracts from DRR206 and defensin transgenic plants inhibited fungal germination in vitro. DRR206 transgenic plants also demonstrated decreased hyphal growth at inoculation sites. While the precise function of DRR206 remains to be determined, these results suggest that it does play an important role in defense against fungi.

2020 ◽  
Vol 48 (3) ◽  
pp. 1276-1291
Author(s):  
Shahina AKTER ◽  
Md. Amdadul HUQ ◽  
Yu-Jin JUNG ◽  
Kwon-Kyoo KANG

  Sweet proteins are the natural alternative to the artificial sweeteners as well as flavor enhancers. Among other sweet protein, thaumatin protein was isolated from Thaumatococcus daniellii Benth plant fruit. In this study, pinII Ti plasmid vector was constructed with thaumatin gene, where thaumatin was placed under the control of the duel cauliflower mosaic virus 35S promoter into rice (Oryza sativa L. var. japonica cv. ‘Dongjinbyeo’) by Agrobacterium-mediated transformation to generate transgenic plants. Thirteen plant lines were regenerated and the transgenic rice lines were confirmed by different molecular analysis. The genomic PCR result revealed that all of the plant lines were transgenic. The single copy and intergenic plant lines were selected by Taqman PCR analysis and FST analysis, respectively. Expression of thaumatin gene in transgenic rice resulted in the accumulation of thaumatin protein in the leave. Thaumatin protein was also accumulated in leave of T1 generation. Sensory analysis result suggested that the thaumatin protein expressing transgenic lines exerted sweet tasting activity. These results demonstrated that thaumatin was expressed in transgenic rice plants.


2008 ◽  
Vol 57 (1-6) ◽  
pp. 235-242 ◽  
Author(s):  
H. Tiimonen ◽  
T. Aronen ◽  
T. Laakso ◽  
P. Saranpää ◽  
V. Chiang ◽  
...  

Abstract The ability of the PtCOMT (caffeate/5-hydroxyferulate O-methyltransferase from Populus tremuloides L.) - modified Betula pendula Roth. lines to form symbiosis with an ectomycorrhizal (ECM) fungus Paxillus involutus Batsch Fr. was studied in vitro. Lignin precursor gene PtCOMT was introduced into two B. pendula clones under the control of the cauliflower mosaic virus 35S promoter or the promoter of the sunflower polyubiquitin gene UbB1. Of the four transgenic lines, one 35SPtCOMT line (23) had a decreased syringyl/guaiacyl (S/G) ratio of root lignin, and two UbB1-PtCOMT lines (110 and 130) retarded root growth compared to the control clone. Both control clones and all transgenic lines were able to form ECMs with P. involutus, but the transgenic lines differed from the controls in the characteristics of the ECMs. The number of lateral roots covered with fungal hyphae and/or development of a Hartig net (HN) were reduced in line 23 with a decreased S/G ratio, and in lines 110 and 130 with slower root formation and changed root morphology, respectively. However, line 23 benefited more from the inoculation in lateral root formation than the control, and in lines 110 and 130 the percentage of viable plants increased most due to inoculation. The results show that B. pendula plants genetically transformed with the lignin gene PtCOMT could form mycorrhizal symbiosis regardless of changes in either the root S/G ratio or development. The benefits of the symbiosis were variable even in the closed in vitro system, and dependent on the clone or transgenic line and the ECM fungal symbiont.


HortScience ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Wanmei Jin ◽  
Jing Dong ◽  
Yuanlei Hu ◽  
Zhongping Lin ◽  
Xuefeng Xu ◽  
...  

Dehydration response element binding (DREB)1b is a cold-inducible transcription factor in Arabidopsis thaliana. DREB1b driven by cauliflower mosaic virus 35S promoter was genetically introduced into grape Vitis vinifera L. cv. Centennial Seedless through Agrobacterium-mediated transformation for improving its cold resistance and exploring new genetic breeding approaches to obtain cold-resistant cultivars. In this study, Southern blot analysis showed the DREB1b gene was integrated into the transgenic grapevines with one to two copies. Northern blot analysis showed the presence of DREB1b transcripts in the independent transgenic lines 3, 5, 6, and 7. Further characterization of transgenic grapevines confirmed that both electrolyte leakage conductivity and the freezing point of the transgenic plants were lower than those of wild-type plants. After the cold treatment at –4 °C for 12 h, 26% of transgenic plants wilted among which 95% plants recovered once being placed under the condition of temperature 22 to 25 °C. However, subjected to the same treatment, 98% of nontransgenic plants wilted and only 2% recovered. Our results lead to the conclusion that activity of DREB1b in the transgenic grape could significantly improve its resistance to cold stress.


2012 ◽  
Vol 39 (9) ◽  
pp. 764 ◽  
Author(s):  
Gi-Ho Lee ◽  
Seong-Han Sohn ◽  
Eun-Young Park ◽  
Young-Doo Park

The chemical modification of DNA by methylation is a heritable trait and can be subsequently reversed without altering the original DNA sequence. Methylation can reduce or silence gene expression and is a component of a host’s defence response to foreign nucleic acids. In our study, we employed a plant transformation strategy using Nicotiana benthamiana Domin to study the heritable stability of the introduced transgenes. Through the introduction of the cauliflower mosaic virus (CaMV) 35S promoter and the green fluorescent protein (GFP) reporter gene, we demonstrated that this introduced promoter often triggers a homology-dependent gene-silencing (HDGS) response. These spontaneous transgene-silencing phenomena are due to methylation of the CaMV 35S promoter CAAT box during transgenic plant growth. This process is catalysed by SU(VAR)3–9 homologue 9 (SUVH9), histone deacetylase 1 (HDA1) and domains rearranged methylase 2 (DRM2). In particular, we showed from our data that SUVH9 is the key regulator of methylation activity in epigenetically silenced GFP transgenic lines; therefore, our findings demonstrate that an introduced viral promoter and transgene can be subject to a homology-dependent gene-silencing mechanism that can downregulate its expression and negatively influence the heritable stability of the transgene.


2005 ◽  
Vol 2 (2) ◽  
pp. 73-77 ◽  
Author(s):  
Li Wei-Min ◽  
Wang Zhi-Xing ◽  
Jia Shi-Rong

AbstractGbRac1 gene was cloned from Gossypium barbadense with degenerate primers and 3′-RACE. Northern blot analysis indicated that GbRac1 mRNA was expressed abundantly in G. barbadense seedlings inoculated with Verticillium dehliae compared with mock-inoculated plants. A plant constitutive expression vector pRac harbouring GbRac1 gene was constructed and leaf discs of tobacco (Nicotiana tabacum L. cv. NC89) were transformed with pRac by Agrobacterium-mediated transformation. Disease challenge test of detached leaves of the transgenic plants by inoculation with Alternaria alternata showed that resistance was enhanced dramatically compared with the non-transgenic plants. Results suggest that GbRac1 gene might have potential application in the genetic engineering of plants with enhanced disease resistance.


2003 ◽  
Vol 373 (3) ◽  
pp. 987-992 ◽  
Author(s):  
Eng-Kiat LIM ◽  
Gillian S. HIGGINS ◽  
Yi LI ◽  
Dianna J. BOWLES

Caffeic acid is a phenylpropanoid playing an important role in the pathways leading to lignin synthesis and the production of a wide variety of secondary metabolites. The compound is also an antioxidant and has potential utility as a general protectant against free radicals. Three glucosylated forms of caffeic acid are known to exist: the 3-O- and 4-O-glucosides and the glucose ester. This study describes for the first time a glucosyltransferase [UDP-glucose:glucosyltransferase (UGT)] that is specific for the 3-hydroxyl, and not the 4-hydroxyl, position of caffeic acid. The UGT sequence of Arabidopsis, UGT71C1, has been expressed as a recombinant fusion protein in Escherichia coli, purified and assayed against a range of substrates in vitro. The assay confirmed that caffeic acid as the preferred substrate when compared with other hydroxycinnamates, although UGT71C1 also exhibited substantial activity towards flavonoid substrates, known to have structural features that can be recognized by many different UGTs. The expression of UGT71C1 in transgenic Arabidopsis was driven by the constitutive cauliflower mosaic virus 35 S (CaMV35S) promoter. Nine independent transgenic lines were taken to homozygosity and characterized by Northern-blot analysis, assay of enzyme activity in leaf extracts and HPLC analysis of the glucosides. The level of expression of UGT71C1 was enhanced considerably in several lines, leading to a higher level of the corresponding enzyme activity and a higher level of caffeoyl-3-O-glucoside. The data are discussed in the context of the utility of UGTs for natural product biotransformations.


2016 ◽  
Vol 66 (5) ◽  
pp. 752-762 ◽  
Author(s):  
X. Zhang ◽  
G. Peng ◽  
P. Parks ◽  
B. Hu ◽  
Q. Li ◽  
...  

2003 ◽  
Vol 370 (1) ◽  
pp. 121-127 ◽  
Author(s):  
Donatella PONTI ◽  
M. LUISA MANGONI ◽  
Giuseppina MIGNOGNA ◽  
Maurizio SIMMACO ◽  
Donatella BARRA

Esculentin-1 is a 46-residue antimicrobial peptide present in skin secretions of Rana esculenta. It is effective against a wide variety of micro-organisms, including plant pathogens with negligible effects on eukaryotic cells. As a possible approach to enhance plant resistance, a DNA coding for esculentin-1, with the substitution Met-28Leu, was fused at the C-terminal end of the leader sequence of endopolygalacturonase-inhibiting protein, under the control of the cauliflower mosaic virus 35S promoter region, and introduced into Nicotiana tabacum. The antimicrobial peptide was isolated from the intercellular fluids of healthy leaves of transgenic plants, suggesting that it was properly processed, secreted outside cells and accumulated in the intercellular spaces. The morphology of transgenic plants was unaffected. Challenging these plants with bacterial or fungal phytopathogens demonstrated enhanced resistance up to the second generation. Moreover, transgenic plants displayed insecticidal properties.


1991 ◽  
Vol 18 (5) ◽  
pp. 495 ◽  
Author(s):  
HE Schroeder ◽  
MRI Khan ◽  
WR Knibb ◽  
D Spencer ◽  
TJV Higgins

Routine procedures have been developed for the transformation of lucerne (Medicago sativa cv. Rangelander) with foreign genes using the Agrobacterium tumefaciens binary vector system and for the regeneration of transgenic plants from tissue culture, via somatic embryogenesis. Lucerne transformation was carried out with a gene encoding neomycin phosphotransferase (npt), which conferred resistance to the antibiotic kanamycin, together with a cDNA clone encoding chicken ovalbumin which was modified for expression in plant cells. The ovalbumin cDNA protein coding sequence was combined with the cauliflower mosaic virus 35S promoter and the nopaline synthase 3' flanking sequence to make a chimeric ovalbumin gene. A DNA construct containing both these genes was transferred to lucerne, and ovalbumin was detected in leaves of regenerated plants using protein immunoblots. Pulse-chase labelling experiments and analysis of leaves from the top to bottom of the transformed plants indicated that ovalbumin, once formed, was stable in the leaves of transgenic lucerne. A wide variation in ovalbumin level was frequently observed in plants regenerated from multiple embryos on a single transformed callus. This variation correlated with changes in the restriction enzyme digestion pattern of the ovalbumin DNA from the transgenic plants. These results indicate that each transformed callus may have arisen from more than one transformation event. An alternative interpretation is that the callus may have arisen from a single transformed cell but during cell proliferation the DNA in some cells may have undergone rearrangement prior to embryogenesis. Transformation and regeneration procedures were also developed for two Australian commercial cultivars of lucerne. Although the frequency of recovery of transformed plants was lower than with cv. Rangelander, these protocols open the way for a relatively rapid


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