Bitter gourd proteinase inhibitors: potential growth inhibitors of Helicoverpa armigera and Spodoptera litura.
Proteinase inhibitors (PIs) from the seeds of bitter gourd (Momordica charantia L.) were identified as strong inhibitors of Helicoverpa armigera gut proteinases (HGP). Biochemical investigations showed that bitter gourd PIs (BGPIs) inhibited more than 80% HGP activity. Electrophoretic analysis revealed the presence of two major proteins (BGPI-1 and-2) and two minor proteins (BGPI-3 and-4) having inhibitory activity against both trypsin and HGP. The major isoforms BGPI-1 and BGPI-2 have molecular mass of 3.5 and 3.0 kDa, respectively. BGPIs inhibited HGP activity of larvae fed on different host plants, on artificial diet with or without added PIs and proteinases excreted in fecal matter. Degradation of BGPI-1 by HGP showed direct correlation with accumulation of BGPI-2-like peptide, which remained stable and active against high concentrations of HGP up to 3 h. Chemical inhibitors of serine proteinases offered partial protection to BGPI-1 from degradation by HGP, suggesting that trypsin and chymotrypsin like proteinases are involved in degradation of BGPI-1. In larval feeding studies, BGPIs were found to retard growth and development of two lepidopteran pests namely Helicoverpa armigera and Spodoptera litura. This is the first report showing that BGPIs mediated inhibition of insect gut proteinases directly affects fertility and fecundity of both H. armigera and S. litura. The results advocate use of BGPIs to introduce insect resistance in otherwise susceptible plants.
Telang
Manasi
M
Plant Molecular Biology Unit, Division of Biochemical Sciences, National Chemical Laboratory, Pune 411 008, India.
Srinivasan
Ajay
A
Patankar
Aparna
A
Harsulkar
Abhay
A
Joshi
Vijay
V
Damle
Archana
A
Deshpande
Vasanti
V
Sainani
Mohini
M
Ranjekar
Prabhakar
P
Gupta
Gorakh
G
Birah
Ajanta
A
Rani
Seema
S
Kachole
Manavendra
M
Giri
Ashok
A
Gupta
Vidya
V
D000818:Animals; D007814:Larva / Q000187:drug effects / Q000201:enzymology; D007915:Lepidoptera / Q000187:drug effects* / Q000201:enzymology*; D029777:Momordica charantia / Q000737:chemistry*; D011480:Protease Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology*; D020033:Protein Isoforms / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D013270:Stomach / Q000201:enzymology; D014357:Trypsin / Q000378:metabolism
D011480:Protease Inhibitors; D020033:Protein Isoforms; D014357:Trypsin