Indica rice cultivar IRGA 424, transformed with cry genes of B. thuringiensis, provided high resistance against Spodoptera frugiperda (Lepidoptera: Noctuidae).
Plant expression of the entomopathogenic bacteria Bacillus thuringiensis cry gene has reduced the damage created by insect pests in several economically important cultures. For this study, we have conducted genetic transformation of the indica rice "IRGA 424", via Agrobacterium tumefaciens, using the B. thuringiensis cry1Aa and cry1B genes, with the objective of obtaining rice plants resistant to the insect pests from this culture. The gene constructions harbor the promoters maize proteinase inhibitor and ubiquitin. The results showed that high concentration of the hormone 2,4-dichlorophenoxyacetic acid and agarose as the gelling agent helped the production of embryogenic calli for the analyzed cultivar. More than 80% of the obtained transformed plants revealed the integration, using polymerase chain reaction, of the cry1Aa and cry1B genes. Analysis of the expression of the heterologous protein by Western blotting revealed the expression of the Cry1B delta-endotoxin in IRGA 424 plants transformed with the ubiquitin promoter. Data showed the production and dissemination of a high number of embryogenic calli in addition to obtaining plants transformed with the cry1Aa and cry1B genes until the reproductive phase. The feed bioassays with the transformed plants and Spodoptera frugiperda (JE Smith) larvae indicated high rates of mortality to the insect target. The highest corrected mortality rate achieved under laboratory conditions with Bt-rice plants transformed with the cry1B and cry1Aa genes was 94 and 84%, respectively. Thus, our results demonstrated the great potential of transformed Bt-rice plants in controlling the damage caused by these insect pests in rice paddy fields.
Universidade do Vale do Rio dos Sinos, Laboratory of Microbiology and Toxicology. CEP, São Leopoldo, RS, Brazil. lauramnp@yahoo.com.br
Laura Massochin Nunes
LM
Pinto
Universidade do Vale do Rio dos Sinos, Laboratory of Microbiology and Toxicology. CEP, São Leopoldo, RS, Brazil.
Lidia Mariana
LM
Fiuza
UNISINOS, IT NUTRIFOR-Technological Institute of Food for Health. CEP 93001-970, São Leopoldo, RS, Brazil.
Denize
D
Ziegler
IRGA, Rice Experiment Station, CEP 94930-030, Cachoerinha, RS, Brazil.
Jaime Vargas
JV
De Oliveira
IRGA, Rice Experiment Station, CEP 94930-030, Cachoerinha, RS, Brazil.
Valmir Gaedke
VG
Menezes
University of Montpellier 2, Bat 15, Montpellier, France.
Isabelle
I
Bourrié
CIRAD, UMR Development and Plant Breeding, Team "Adaptive Development of Rice," Agropolis, 34398 Montpellier, France.
Donaldo
D
Meynard
CIRAD, UMR Development and Plant Breeding, Team "Adaptive Development of Rice," Agropolis, 34398 Montpellier, France.
Emmanuel
E
Guiderdoni
CIRAD, UMR Development and Plant Breeding, Team "Adaptive Development of Rice," Agropolis, 34398 Montpellier, France.
Jean-Christophe
JC
Breitler
Biochemistry Microbiology & Immunology Department, University of Ottawa, Ontario K1H 8M5, Canada.
Illimar
I
Altosaar
University of Montpellier 2, Bat 15, Montpellier, France.
Pascal
P
Gantet
D060054:Agrobacterium / Q000235:genetics; D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D004731:Endotoxins / Q000235:genetics* / Q000378:metabolism; D006460:Hemolysin Proteins / Q000235:genetics* / Q000378:metabolism; D060434:Herbivory; D007814:Larva / Q000254:growth & development / Q000502:physiology; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified / Q000235:genetics*; D016133:Polymerase Chain Reaction; D018411:Spodoptera / Q000254:growth & development / Q000502:physiology*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis