Analysis of unstable RNA transcripts of insecticidal crystal protein genes of Bacillus thuringiensis in transgenic plants and electroporated protoplasts

Murray, Elizabeth E.; Rocheleau, Thomas A.; Eberle, Mary; Stock, Carolyn; Sekar, Vaithilingam; Adang, Michael J.

doi:10.1007/bf00016075

Cited by 124 publications

(63 citation statements)

References 61 publications

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“…Some mRNAs in plants and yeast are thought to be destabilized because they include rare codons that cause the ribosome to stall during translation (Hoekemaet al, 1987;Murray et al, 1991). A comparison of PHYA mRNA codon usage to the average codon usage of 207 plant genes (Murray et al, 1991) indicated that PHYA mRNA contains a distribution of codons that closely fits the average plant codon usage distribution (data not shown), suggesting that PHYA mRNA is not destabilized by this mechanism.…”

Section: Discussionmentioning

confidence: 98%

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Oat phytochrome A mRNA degradation appears to occur via two distinct pathways.

Higgs

Colbert

1994

Plant Cell

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Section: Discussionmentioning

confidence: 98%

“…A comparison of PHYA mRNA codon usage to the average codon usage of 207 plant genes (Murray et al, 1991) indicated that PHYA mRNA contains a distribution of codons that closely fits the average plant codon usage distribution (data not shown), suggesting that PHYA mRNA is not destabilized by this mechanism.…”

Section: Discussionmentioning

confidence: 99%

Oat phytochrome A mRNA degradation appears to occur via two distinct pathways.

Higgs

Colbert

1994

Plant Cell

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“…The significance of identifying the most effective ICP has been pointed out (32). Since native cry genes have poor coding capacity in plants (33), the cryIAc gene was duly reconstructed.…”

Section: Discussionmentioning

confidence: 99%

Transgenic elite indica rice plants expressing CryIAc ∂-endotoxin of Bacillus thuringiensis are resistant against yellow stem borer ( Scirpophaga incertulas )

Nayak

Basu²,

Das³

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

218

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Generation of insect-resistant, transgenic crop plants by expression of the insecticidal crystal protein (ICP) gene of Bacillus thuringiensis (Bt) is a standard crop improvement approach. In such cases, adequate expression of the most appropriate ICP against the target insect pest of the crop species is desirable. It is also considered advantageous to generate Bt-transgenics with multiple toxin systems to control rapid development of pest resistance to the ICP. Larvae of yellow stem borer (YSB), Scirpophaga incertulas, a major lepidopteran insect pest of rice, cause massive losses of rice yield. Studies on insect feeding and on the binding properties of ICP to brush border membrane receptors in the midgut of YSB larvae revealed that cryIAb and cryIAc are two individually suitable candidate genes for developing YSB-resistant rice. Programs were undertaken to develop Bt-transgenic rice with these ICP genes independently in a single cultivar. A cryIAc gene was reconstructed and placed under control of the maize ubiquitin 1 promoter, along with the first intron of the maize ubiquitin 1 gene, and the nos terminator. The gene construct was delivered to embryogenic calli of IR64, an elite indica rice cultivar, using the particle bombardment method. Six highly expressive independent transgenic ICP lines were identified. Molecular analyses and insect-feeding assays of two such lines revealed that the transferred synthetic cryIAc gene was expressed stably in the T 2 generation of these lines and that the transgenic rice plants were highly toxic to YSB larvae and lessened the damage caused by their feeding.Technologies of plant cell biology and molecular biology have attracted much attention because they provide a powerful and novel means to supplement as well as complement the traditional methods of crop improvement. The transgenic approach of plant genetic engineering provides access to an unlimited gene pool for the transfer of desirable genes between any two species of interest, irrespective of their evolutionary or taxonomic relation. The successful generation of transgenic insectresistant crop plants by transferring the insecticidal crystal protein (ICP) gene of Bacillus thuringiensis (Bt; refs. 1-8), a Gram-positive, spore-forming bacterium, is one of the major breakthroughs in crop science that the new genetics has provided.indica rice is one of the most important food crops (9) of the world. There are half a dozen different species of lepidopteran insects whose larvae bore into the tissue of rice plants, and the resultant damage causes massive yield losses (10). Yellow stem borer (YSB), Scirpophaga incertulas, is most certainly the major contributor to these losses. The first-stage YSB larvae cut small holes in the stem of the paddy plant and enter the plant tissue, remaining there for the rest of their lives as larvae and pupae. The larvae feed voraciously inside the stem, providing themselves complete protection against chemical pesticides. There are no known resistance genes in rice (11) that can be rea...

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“…The wild type cry1Ab gene corresponded to the amino acid positions 29 to 618. According to the Northern blot analysis, the sequence of the 56 kDa protein obtained from the wild type cry1Ab gene might have been interrupted at the ATTTA sequences of 1.6 kb (Murray et al 1991) and not digested at the second trypsin cleavage site of the amino acids at positions 601 and 602. Survival pattern of H. armigera reared on the mcbttransformed lines was significantly different from that of the insects reared on the non-transformed control, when the expression level of Cry1Ab ICP in the mcbt-transformed lines exceeded 12.3 ng per 50 µg.…”

Section: Discussionmentioning

confidence: 99%

“…The low level of expression of the Bt gene in plants is due to mRNA instability (Ohme- Takagi et al 1993, Chen andShyu 1995), which mainly results from the presence of ATTTA sequences (Murray et al 1991, Van Aarssen et al 1995. Modification of the coding sequences successfully enhanced plant expression of Bt genes (Perlak et al 1990, Sutton et al 1992, Adang et al 1993, Koziel et al 1993.…”

Section: Introductionmentioning

confidence: 99%