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Transgenic Cotton Plants Expressing Double-stranded RNAs Target HMG-CoA Reductase (HMGR) Gene Inhibits the Growth, Development and Survival of Cotton Bollworms.

Tian G, Cheng L, Qi X, Ge Z, Niu C, Zhang X, Jin S - Int. J. Biol. Sci. (2015)

Bottom Line: In this report, double-stranded RNAs (dsRNA) targeting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) gene, which catalyze a rate-limiting enzymatic reaction in the mevalonate pathway of juvenile hormone (JH) synthesis in cotton bollworm, was expressed in cotton plants via Agrobacterium tumefaciens-mediated transformation.In addition, the relative expression level of vitellogenin (Vg, crucial source of nourishment for offspring embryo development) gene was also reduced by 76.86% when the insect larvae were fed with transgenic leaves.The result of insect bioassays showed that the transgenic plant harboring dsHMGR not only inhibited net weight gain but also delayed the growth of cotton bollworm larvae.

View Article: PubMed Central - PubMed

Affiliation: College of Plant Science and Technology, National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, P.R. China.

ABSTRACT
RNA interference (RNAi) has been developed as a powerful technique in the research of functional genomics as well as plant pest control. In this report, double-stranded RNAs (dsRNA) targeting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) gene, which catalyze a rate-limiting enzymatic reaction in the mevalonate pathway of juvenile hormone (JH) synthesis in cotton bollworm, was expressed in cotton plants via Agrobacterium tumefaciens-mediated transformation. PCR and Sothern analysis revealed the integration of HMGR gene into cotton genome. RT-PCR and qRT-PCR confirmed the high transcription level of dsHMGR in transgenic cotton lines. The HMGR expression both in transcription and translation level was significantly downregulated in cotton bollworms (helicoverpa armigera) larvae after feeding on the leaves of HMGR transgenic plants. The transcription level of HMGR gene in larvae reared on transgenic cotton leaves was as much as 80.68% lower than that of wild type. In addition, the relative expression level of vitellogenin (Vg, crucial source of nourishment for offspring embryo development) gene was also reduced by 76.86% when the insect larvae were fed with transgenic leaves. The result of insect bioassays showed that the transgenic plant harboring dsHMGR not only inhibited net weight gain but also delayed the growth of cotton bollworm larvae. Taken together, transgenic cotton plant expressing dsRNAs successfully downregulated HMGR gene and impaired the development and survival of target insect, which provided more option for plant pest control.

No MeSH data available.


Related in: MedlinePlus

Quantification of larvae lethality after feeding on transgenic dsHMGR cotton leaves. For the insect bioassay, 20 newly-hatched cotton bollworm larvae were reared on the detached fresh leaves from  plants as control and two positive transgenic lines. The lethality of different groups was detected every 12 hours. Leaves of positive plants expressing dsRNA-HMGR bring about higher lethality than those of  plants (CK). The test was repetitiously performed for three times. The student's t-test was used to perform the statistical analyses of the data. **statistically significant at 0.01; *statistically significant at 0.05.
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Figure 6: Quantification of larvae lethality after feeding on transgenic dsHMGR cotton leaves. For the insect bioassay, 20 newly-hatched cotton bollworm larvae were reared on the detached fresh leaves from plants as control and two positive transgenic lines. The lethality of different groups was detected every 12 hours. Leaves of positive plants expressing dsRNA-HMGR bring about higher lethality than those of plants (CK). The test was repetitiously performed for three times. The student's t-test was used to perform the statistical analyses of the data. **statistically significant at 0.01; *statistically significant at 0.05.

Mentions: Bioassay of newly-hatched cotton bollworm larvae was performed to testify the lethality by dsHMGR-transgenic plants. The results showed that line HMGi2-49 exhibited higher mortality than line HMGi1-13. However, mortalities resulting from both lines were significantly higher than those of negative control plants at the first 48 hours of bioassay (Fig. 6). After 72 hours, all of the larvae surviving the test kept alive, making the lethality of each group remained unchangeable. Therefore, the results after 96 hours were not illustrated. It was easily to find out that the transgenic cotton leaves expressing dsHMGR caused higher lethality in newly-hatched cotton bollworm larvae, while the survived larvae could keep alive after 72 hours no matter if their food contains dsHMGR or not. A probable explanation is that the tolerance increased with aging may endow larvae with enough ability to bear the lethality brought by dsRNA, while young larvae were sensitive to the dsRNA. In addition, larvae fed on line HMGi2-49 presented higher lethality than HMGi1-13, although the relative expression level of HMGi2-49 was no more than half of HMGi1-13. So we inferred that HMGi2 target sequence in RNA interference vector may be more effective than HMGi1 target sequence on the lethality of young larvae.


Transgenic Cotton Plants Expressing Double-stranded RNAs Target HMG-CoA Reductase (HMGR) Gene Inhibits the Growth, Development and Survival of Cotton Bollworms.

Tian G, Cheng L, Qi X, Ge Z, Niu C, Zhang X, Jin S - Int. J. Biol. Sci. (2015)

Quantification of larvae lethality after feeding on transgenic dsHMGR cotton leaves. For the insect bioassay, 20 newly-hatched cotton bollworm larvae were reared on the detached fresh leaves from  plants as control and two positive transgenic lines. The lethality of different groups was detected every 12 hours. Leaves of positive plants expressing dsRNA-HMGR bring about higher lethality than those of  plants (CK). The test was repetitiously performed for three times. The student's t-test was used to perform the statistical analyses of the data. **statistically significant at 0.01; *statistically significant at 0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4582153&req=5

Figure 6: Quantification of larvae lethality after feeding on transgenic dsHMGR cotton leaves. For the insect bioassay, 20 newly-hatched cotton bollworm larvae were reared on the detached fresh leaves from plants as control and two positive transgenic lines. The lethality of different groups was detected every 12 hours. Leaves of positive plants expressing dsRNA-HMGR bring about higher lethality than those of plants (CK). The test was repetitiously performed for three times. The student's t-test was used to perform the statistical analyses of the data. **statistically significant at 0.01; *statistically significant at 0.05.
Mentions: Bioassay of newly-hatched cotton bollworm larvae was performed to testify the lethality by dsHMGR-transgenic plants. The results showed that line HMGi2-49 exhibited higher mortality than line HMGi1-13. However, mortalities resulting from both lines were significantly higher than those of negative control plants at the first 48 hours of bioassay (Fig. 6). After 72 hours, all of the larvae surviving the test kept alive, making the lethality of each group remained unchangeable. Therefore, the results after 96 hours were not illustrated. It was easily to find out that the transgenic cotton leaves expressing dsHMGR caused higher lethality in newly-hatched cotton bollworm larvae, while the survived larvae could keep alive after 72 hours no matter if their food contains dsHMGR or not. A probable explanation is that the tolerance increased with aging may endow larvae with enough ability to bear the lethality brought by dsRNA, while young larvae were sensitive to the dsRNA. In addition, larvae fed on line HMGi2-49 presented higher lethality than HMGi1-13, although the relative expression level of HMGi2-49 was no more than half of HMGi1-13. So we inferred that HMGi2 target sequence in RNA interference vector may be more effective than HMGi1 target sequence on the lethality of young larvae.

Bottom Line: In this report, double-stranded RNAs (dsRNA) targeting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) gene, which catalyze a rate-limiting enzymatic reaction in the mevalonate pathway of juvenile hormone (JH) synthesis in cotton bollworm, was expressed in cotton plants via Agrobacterium tumefaciens-mediated transformation.In addition, the relative expression level of vitellogenin (Vg, crucial source of nourishment for offspring embryo development) gene was also reduced by 76.86% when the insect larvae were fed with transgenic leaves.The result of insect bioassays showed that the transgenic plant harboring dsHMGR not only inhibited net weight gain but also delayed the growth of cotton bollworm larvae.

View Article: PubMed Central - PubMed

Affiliation: College of Plant Science and Technology, National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, P.R. China.

ABSTRACT
RNA interference (RNAi) has been developed as a powerful technique in the research of functional genomics as well as plant pest control. In this report, double-stranded RNAs (dsRNA) targeting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) gene, which catalyze a rate-limiting enzymatic reaction in the mevalonate pathway of juvenile hormone (JH) synthesis in cotton bollworm, was expressed in cotton plants via Agrobacterium tumefaciens-mediated transformation. PCR and Sothern analysis revealed the integration of HMGR gene into cotton genome. RT-PCR and qRT-PCR confirmed the high transcription level of dsHMGR in transgenic cotton lines. The HMGR expression both in transcription and translation level was significantly downregulated in cotton bollworms (helicoverpa armigera) larvae after feeding on the leaves of HMGR transgenic plants. The transcription level of HMGR gene in larvae reared on transgenic cotton leaves was as much as 80.68% lower than that of wild type. In addition, the relative expression level of vitellogenin (Vg, crucial source of nourishment for offspring embryo development) gene was also reduced by 76.86% when the insect larvae were fed with transgenic leaves. The result of insect bioassays showed that the transgenic plant harboring dsHMGR not only inhibited net weight gain but also delayed the growth of cotton bollworm larvae. Taken together, transgenic cotton plant expressing dsRNAs successfully downregulated HMGR gene and impaired the development and survival of target insect, which provided more option for plant pest control.

No MeSH data available.


Related in: MedlinePlus