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Toxic effect of destruxin A on abnormal wing disc-like (SLAWD) in Spodoptera litura fabricius (Lepidoptera: Noctuidae).

Meng X, Hu J, Xu X, Wang Z, Hu Q, Jin F, Ren S - PLoS ONE (2013)

Bottom Line: To further understand the effect of DA on SLAWD expression, a functional study was carried out.The results showed a significant decrease in SLAWD mRNA expression levels between the prepupal and adult stages.Interestingly, SLAWD expression was similarly down-regulated by treating 6th-stage larvae with DA.

View Article: PubMed Central - PubMed

Affiliation: Engineering Research Center of Biological Control, Ministry of Education, South China Agricultural University, Guangzhou, China.

ABSTRACT

Background: Destruxin A (DA) is a microbial insecticide with potent bioactivity against Spodoptera litura larvae. A previous proteomic analysis of S. litura (SL-1) cells exposed to DA showed the abnormal expression of wing disc-like protein of S. litura (SLAWD). To further understand the effect of DA on SLAWD expression, a functional study was carried out.

Principal findings: The SLAWD gene (SLAWD) was cloned and an open reading frame of 537 bp encoding a polypeptide of 178 amino acids was detected. Real-time fluorescence quantitative PCR (qRT-PCR) suggested that SLAWD is expressed in all developmental stages of S. litura, but expression was highest during the pupal and adult stages. RNAi knockdown of SLAWD expression in 6th-stage larvae was achieved by the microinjection of a specific double-stranded RNA (dsRNA). The results showed a significant decrease in SLAWD mRNA expression levels between the prepupal and adult stages. Interestingly, SLAWD expression was similarly down-regulated by treating 6th-stage larvae with DA. Growth- and development-related statistics confirmed the observed abnormalities in S. litura development after either RNAi or DA treatment.

Conclusions: SLAWD appears to have a biosynthetic function in the pupal and adult stages of S. litura. The toxic effect of DA on S. litura development is due the negative effect of DA on SLAWD gene expression.

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Related in: MedlinePlus

Phenotypic analysis of S. litura after RNAi and DA treatment.A: Percentage mortality 24 h after RNAi or DA treatment; B: Percentage of normal pupation; C: Percentage of normal eclosion; D: Cumulative mortality of S. litura. The different letters above the columns indicate significant differences in SLAWD expression after RNAi or DA treatment (P<0.05).
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pone-0057213-g007: Phenotypic analysis of S. litura after RNAi and DA treatment.A: Percentage mortality 24 h after RNAi or DA treatment; B: Percentage of normal pupation; C: Percentage of normal eclosion; D: Cumulative mortality of S. litura. The different letters above the columns indicate significant differences in SLAWD expression after RNAi or DA treatment (P<0.05).

Mentions: The phenotypes of S. litura following RNAi or DA treatment are shown in Fig. 6. S. litura entered the prepupal stage during the 24 h following microinjection of dsRNA or DA (Fig. 6 a,b,c). The growth and development of the insects in the three controls was normal and no unusual phenotypes were observed. However, in some of the 6th-stage larvae injected with dsSLAWD or DA, development was delayed and melanization of the lateral tracheae was observed in several of the larvae and prepupae. Further notable effects of DA, but not of dsSLAWD, were seriously melanization and carbonization during development of S. litura. The severity of these effects led to stiffening of the bodies of 6th-stage larvae, and resulted in larval death. Statistical analyses of growth and development showed a significant difference between the mortality in the DA group (30.83±3.96%) and that in the controls after 24 hrs (CK: 2.50±1.12%;CK DEPC water: 2.50±1.12%; CK dsGFP: 4.17±1.54%). There was no obvious difference between mortality in the RNAi group (8.33±2.47%) and that in the corresponding controls (Fig. 7 A).


Toxic effect of destruxin A on abnormal wing disc-like (SLAWD) in Spodoptera litura fabricius (Lepidoptera: Noctuidae).

Meng X, Hu J, Xu X, Wang Z, Hu Q, Jin F, Ren S - PLoS ONE (2013)

Phenotypic analysis of S. litura after RNAi and DA treatment.A: Percentage mortality 24 h after RNAi or DA treatment; B: Percentage of normal pupation; C: Percentage of normal eclosion; D: Cumulative mortality of S. litura. The different letters above the columns indicate significant differences in SLAWD expression after RNAi or DA treatment (P<0.05).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585292&req=5

pone-0057213-g007: Phenotypic analysis of S. litura after RNAi and DA treatment.A: Percentage mortality 24 h after RNAi or DA treatment; B: Percentage of normal pupation; C: Percentage of normal eclosion; D: Cumulative mortality of S. litura. The different letters above the columns indicate significant differences in SLAWD expression after RNAi or DA treatment (P<0.05).
Mentions: The phenotypes of S. litura following RNAi or DA treatment are shown in Fig. 6. S. litura entered the prepupal stage during the 24 h following microinjection of dsRNA or DA (Fig. 6 a,b,c). The growth and development of the insects in the three controls was normal and no unusual phenotypes were observed. However, in some of the 6th-stage larvae injected with dsSLAWD or DA, development was delayed and melanization of the lateral tracheae was observed in several of the larvae and prepupae. Further notable effects of DA, but not of dsSLAWD, were seriously melanization and carbonization during development of S. litura. The severity of these effects led to stiffening of the bodies of 6th-stage larvae, and resulted in larval death. Statistical analyses of growth and development showed a significant difference between the mortality in the DA group (30.83±3.96%) and that in the controls after 24 hrs (CK: 2.50±1.12%;CK DEPC water: 2.50±1.12%; CK dsGFP: 4.17±1.54%). There was no obvious difference between mortality in the RNAi group (8.33±2.47%) and that in the corresponding controls (Fig. 7 A).

Bottom Line: To further understand the effect of DA on SLAWD expression, a functional study was carried out.The results showed a significant decrease in SLAWD mRNA expression levels between the prepupal and adult stages.Interestingly, SLAWD expression was similarly down-regulated by treating 6th-stage larvae with DA.

View Article: PubMed Central - PubMed

Affiliation: Engineering Research Center of Biological Control, Ministry of Education, South China Agricultural University, Guangzhou, China.

ABSTRACT

Background: Destruxin A (DA) is a microbial insecticide with potent bioactivity against Spodoptera litura larvae. A previous proteomic analysis of S. litura (SL-1) cells exposed to DA showed the abnormal expression of wing disc-like protein of S. litura (SLAWD). To further understand the effect of DA on SLAWD expression, a functional study was carried out.

Principal findings: The SLAWD gene (SLAWD) was cloned and an open reading frame of 537 bp encoding a polypeptide of 178 amino acids was detected. Real-time fluorescence quantitative PCR (qRT-PCR) suggested that SLAWD is expressed in all developmental stages of S. litura, but expression was highest during the pupal and adult stages. RNAi knockdown of SLAWD expression in 6th-stage larvae was achieved by the microinjection of a specific double-stranded RNA (dsRNA). The results showed a significant decrease in SLAWD mRNA expression levels between the prepupal and adult stages. Interestingly, SLAWD expression was similarly down-regulated by treating 6th-stage larvae with DA. Growth- and development-related statistics confirmed the observed abnormalities in S. litura development after either RNAi or DA treatment.

Conclusions: SLAWD appears to have a biosynthetic function in the pupal and adult stages of S. litura. The toxic effect of DA on S. litura development is due the negative effect of DA on SLAWD gene expression.

Show MeSH
Related in: MedlinePlus