Uraria picta is a medicinally important ‘dashmula’ plant found in dry grasslands of India and is ... more Uraria picta is a medicinally important ‘dashmula’ plant found in dry grasslands of India and is facing overexploitation in wilds. Its roots have been used in traditional treatments while in modern medicine it is known to promote osteogenesis and possess anti-cancer properties. Rhizobium rhizogenes ATCC-15834 was used to induce hairy roots (HR) in in vitro raised U. picta seedlings. This is the first report of U. picta HR induction and characterization. The comparative biochemical and functional analysis showed that U. picta true roots (TR) and HR extracts display high free radical scavenging activity (~ 84%) and higher cytotoxic activity in cancer cell lines HeLa (71.18%) and MCF-7 (89.36%) as compared to the normal cell line HEK (58.87%). There was a twofold increase in HR biomass upon jasmonic acid (JA) treatment, while salicylic acid (SA) and abscisic acid (ABA) had no significant effects, though ABA led to increase in the HR thickness. In comparative metabolomics HR-LC/MS study, 39% metabolites were commonly detected in TR, HR and Hairy root exudates (HREx). Major chemical classes of the metabolites detected were lipids, benzenoids and organic acids represented by glutinone; estra-1,3,5(10)-triene-3,6 beta, 17 beta-triol triacetate; azokisaponin III; gingerol, shogaol and mucronine B with well-known therapeutic potentials. Additionally, a high proportion of unknown masses were also found in U. picta TR, HR and HREx, which needs further investigation. Due to the parallels in the biochemical, metabolomic and functional aspects of TR and HR, U. picta HR represents a sustainable alternative source of U. picta bioactives. Comparative metabolomics reveals similarities in the hairy roots and true roots of Uraria picta, making it a suitable biotechnological alternative for biosynthesis of specialized metabolites.
The inert and surface tunable nature of silica nanoparticles (SiNPs) makes them suitable for diff... more The inert and surface tunable nature of silica nanoparticles (SiNPs) makes them suitable for different applications. We have evaluated the potential of SiNPs for delivering proteins in tomato (Lycopersicon esculentum) plants. SiNPs of 20 and 100 nm (Si20 and Si100) were functionalized with (3-aminopropyl) triethoxysilane (APTES) to obtain Si20APT and Si100APT, respectively, that were non-toxic toward plants. The functionalized nanoparticles were taken up by plants through roots as well as leaf surfaces. They were seen to be localized near the vasculature, particularly around the xylem. Si20APT and Si100APT nanoparticles were conjugated with soybean trypsin inhibitor (STI) to yield Si20APT-STI and Si100APT-STI, respectively. Based on the trypsin inhibitory activity of loaded nanoparticles, optimum loading was obtained for 0.4 mg of STI per 0.8 mg of NPs. Si20APT nanoparticles retained higher contents of STI than Si100APT. Exposure of STI-conjugated nanoparticles to 25°C or pH 8.0 aided release of the inhibitor. The particle bound STI inhibited bovine trypsin by 80% and Helicoverpa armigera gut proteinase (HGP) activity by 50%. Second instar H. armigera larvae ingesting STI-loaded particles (incorporated in artificial diet or leaves) showed significant retardation in growth. In choice assays, Si20APT-STI applied leaf discs were strikingly avoided by insect larvae. On the basis of the results obtained in this investigation, we recommend the use of Si20 nanoparticles for developing plant delivery vehicles in the future.
ABSTRACTPhylogenetic diversity of culturable actinobacteria isolated from the intertidal regions ... more ABSTRACTPhylogenetic diversity of culturable actinobacteria isolated from the intertidal regions of west coast of Maharashtra, India was studied using 16S rRNA gene sequencing. Total of 140 actinobacterial isolates were obtained, which belonged to 14 genera, 10 families and 65 putative species with Streptomyces being the most dominant (63%) genus followed by Nocardiopsis and Micromonospora. They were screened for production of extracellular protease inhibitors (PI) against three pure proteases viz. chymotrypsin, trypsin, subtilisin and one crude extracellular protease from Pseudomonas aeruginosa. Eighty percent of the isolates showed PI activity against at least one of the four proteases, majority of them belonged to genus Streptomyes. Actinobacterial diversity from two sites Ade (17°52′ N, 73°04′ E) and Harnai (17°48′ N, 73°05′ E) with varying degree of anthropological pressure showed that more putative species diversity was obtained from site with lower human intervention i.e Ade ...
Phylogenetic diversity of cultivable actinobacteria isolated from sponges and associated environm... more Phylogenetic diversity of cultivable actinobacteria isolated from sponges and associated environments of intertidal zones, along the northern parts of west coast of India, were studied using 16S rRNA gene sequences. A subset of actinobacteria were screened for three activities, namely predatory behavior, antibacterial activity and enzyme inhibition. We recovered 207 isolates of actinobacteria belonging to 16 families and 25 genera, which could be attributed to 55 putative species using Poisson Tree Processes and 60 putative species based on Bayesian Poisson Tree Processes. Although the trends in the discovery of actinobacterial genera isolated from sponges was consistent with previous studies from different study areas, we provide first report of six actinobacterial species from sponges. We observed widespread non-obligate epibiotic predatory behavior in eight actinobacterial genera and we provide first report of predatory activity in Brevibacterium, Glutamicibacter, Micromonospora,...
Thionins are small, cysteine‐rich peptides that play an important role in plant defense, primaril... more Thionins are small, cysteine‐rich peptides that play an important role in plant defense, primarily through their interactions with membranes. Eight novel γ‐thionin peptides (CanThio1‐8) were isolated from the flower of Capsicum annuum. Sequence analysis revealed that the peptides cluster into three groups. A representative peptide from each group (CanThio1, 2, and 3) was used for experimental characterization. Interestingly, peptides were found to possess some cytotoxic activity against normal human embryonic kidney cell line but higher cytotoxicity against cancer cell line MCF‐7. CanThio3 peptide was chosen as a representative peptide to study the molecular mechanism of action on membranes. Microsecond timescale atomistic simulations of CanThio3 were performed in the presence of a POPC (1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine) lipid bilayer. Simulations revealed that CanThio3 interacts with the bilayer and causes lipid thinning in the vicinity. Nonpolar amino acids specific to the α‐core region of CanThio3 along with nonpolar residues in the γ‐core region are seen to interact with the lipid tails. The differences in the amino acid sequence of CanThio peptides in these regions explain the variability in cytotoxic activities. In summary, our results demonstrate the membrane‐mediated activity of a novel series of γ‐thionin peptides from C. annuum.
Oroxylum indicum (L.) Kurz is a medicinally important and rare tree species of the family Bignoni... more Oroxylum indicum (L.) Kurz is a medicinally important and rare tree species of the family Bignoniaceae. It is rich in flavonoid content and its mature roots are extensively used in Ayurvedic formulations. O. indicum specific flavonoids like oroxylin B, prunetin and oroxindin possess antibacterial, antiproliferative, antioxidant and anticancerous properties, signifying its importance in modern medicine. In the present study, de novo transcriptome analysis of O. indicum root was performed to elucidate the genes involved in flavonoid metabolism. A total of 24,625,398 high quality reads were assembled into 121,286 transcripts with N50 value 1783. The BLASTx search of 81,002 clustered transcripts against Viridiplantae Uniprot database led to annotation of 46,517 transcripts. Furthermore, Gene ontology (GO) revealed that 34,231 transcripts mapped to 3049 GO terms and KEGG analysis demonstrated that 4570 transcripts plausibly involved in 132 biosynthetic pathways. The transcriptome data indicated that cinnamyl-alcohol dehydrogenase (OinCAD) was abundant in phenylpropanoid pathway genes while; naringenin chalcone synthase (OinCHS), flavone synthase (OinFNS) and flavonoid 3', 5'-methyltransferase (OinF35 MT) were abundant in flavonoid, isoflavonoid, flavone and flavonol biosynthesis pathways, respectively. Transcription factor analysis demonstrated the abundance of MYB, bHLH and WD40 transcription factor families, which regulate the flavonoid biosynthesis. Flavonoid pathway genes displayed differential expression in young and old roots of O. indicum. The transcriptome led to the identification of 31 diverse full length Cytochrome P450 (CYP450) genes which may be involved in biosynthesis of specialized metabolites and flavonoids like baicalein and baicalin. Thus, the information obtained in this study will be a valuable tool for identifying genes and developing system biology approaches for in vitro synthesis of specialized O. indicum metabolites.
The present invention relates to a method for pest management using inhibitory repeat domain IRD ... more The present invention relates to a method for pest management using inhibitory repeat domain IRD 9 (Seq ID No.2) proteinase inhibitor showing enhanced inhibitory activity against the gut proteases of insects. More particularly, the present invention relates to a IRD 9 (Seq ID No.2) proteinase inhibitor from non-host plant Capsicum annuum, which possesses significantly high insect protease inhibition activity against the gut proteases of Helicoverpa armigera.
Helicoverpa armigera (Lepidoptera: Noctuidae) and other polyphagous agricultural pests are extend... more Helicoverpa armigera (Lepidoptera: Noctuidae) and other polyphagous agricultural pests are extending their plant host range and emerging as serious agents in restraining crop productivity. Dynamic regulation, coupled with a diversity of digestive and detoxifying enzymes, play a crucial role in the adaptation of polyphagous insects. To investigate the functional intricacy of serine proteases in the development and polyphagy of H. armigera, we profiled the expression of eight trypsin-like and four chymotrypsin-like phylogenetically diverse mRNAs from different life stages of H. armigera reared on nutritionally distinct host plants. These analyses revealed diet- and stage-specific protease expression patterns. The trypsins expressed showed structural variations, which might result in differential substrate specificity and interaction with inhibitors. Protease profiles in the presence of inhibitors and their mass spectrometric analyses revealed insight into their differential activity. These findings emphasize the differential expression of serine proteases and their consequences for digestive physiology in promoting polyphagy in H. armigera.
Biochimica et Biophysica Acta (BBA) - General Subjects, 2013
A multi-domain Pin-II type protease inhibitor from Capsicum annuum (CanPI-7) is known to be effec... more A multi-domain Pin-II type protease inhibitor from Capsicum annuum (CanPI-7) is known to be effective against the insect pest, Helicoverpa armigera. The present study is an attempt to investigate the optimal dose of recombinant CanPI-7 (rCanPI-7) for effective antibiosis to H. armigera and further to characterize the responses of digestive proteases upon rCanPI-7 ingestion. The gut protease activity was assessed biochemically and transcript accumulation pattern for selected trypsin and chymotrypsin genes was analyzed by quantitative Real-Time PCR. The growth retardation upon exposure to rCanPI-7 was more prominent in neonates as compared to third instar larvae. Influence of stage and dosage of rCanPI-7 was conspicuous on the expression and regulation of candidate trypsin and chymotrypsin genes in H. armigera. The transcript accumulation pattern correlated with the protease activity in rCanPI-7 exposed larvae. We conclude that early exposure and specific dose of protease inhibitor are essential for effective antibiosis despite the large diversity and plasticity in the expression of protease genes in H. armigera. Moreover, it is also evident that the regulation and expression of H. armigera gut proteases are specific to the stage of PI exposure. These results highlight the requirement of optimal PI concentration for effective growth retardation and for inhibiting the major gut proteases of H. armigera.
Capsicum annuum (L.) expresses diverse potato type II family proteinase inhibitors comprising of ... more Capsicum annuum (L.) expresses diverse potato type II family proteinase inhibitors comprising of inhibitory repeat domain (IRD) as basic functional unit. Most IRDs contain eight conserved cysteines forming four disulfide bonds, which are indispensible for their stability and activity. We investigated the functional significance of evolutionary variations in IRDs and their role in mediating interaction between the inhibitor and cognate proteinase. Among the 18 IRDs encoded by C. annuum, IRD-7, -9, and -12 were selected for further characterization on the basis of variation in their reactive site loop, number of conserved cysteine residues, and higher theoretical ΔGbind for interaction with Helicoverpa armigera trypsin. Moreover, inhibition kinetics showed that IRD-9, despite loss of some of the disulfide bonds, was a more potent proteinase inhibitor among the three selected IRDs. Molecular dynamic simulations revealed that serine residues in the place of cysteines at seventh and eighth positions of IRD-9 resulted in an increase in the density of intramolecular hydrogen bonds and reactive site loop flexibility. Results of the serine residues chemical modification also supported this observation and provided a possible explanation for the remarkable inhibitory potential of IRD-9. Furthermore, this natural variant among IRDs showed special attributes like stability to proteolysis and synergistic inhibitory effect on other IRDs. It is likely that IRDs have coevolved selective specialization of their structure and function as a response towards specific insect proteases they encountered. Understanding the molecular mechanism of pest protease-plant proteinaceous inhibitor interaction will help in developing effective pest control strategies. An animated interactive 3D complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:39.
F il I n s Helicoverpa armigera: Ecology and Control Using Novel Biotechnological Approaches Va... more F il I n s Helicoverpa armigera: Ecology and Control Using Novel Biotechnological Approaches Vaijayanti A. Tamhane Ashok P. Giri Vidya S. Gupta Plant Molecular Biology Unit, Division of Biochemical ... 7. Wilkins, TA; Rajasekaran, K.; Anderson, DM Cotton biotechnology. Crit. ...
Background Spotted stem borer- Chilo partellus - a Lepidopteran insect pest of Sorghum bicolor is... more Background Spotted stem borer- Chilo partellus - a Lepidopteran insect pest of Sorghum bicolor is responsible for major economic losses. It is an oligophagous pest, which bores through the plant stem, causing ‘deadheart’ and hampering the development of the main cob. We applied a label-free quantitative proteomics approach on three genotypes of S. bicolor with differential resistance/ susceptibility to insect pests, intending to identify the S. bicolor’s systemic protein complement contributing to C. partellus tolerance. Methods The proteomes of S. bicolor with variable resistance to insect pests, ICSV700, IS2205 (resistant) and Swarna (susceptible) were investigated and compared using label-free quantitative proteomics to identify putative leaf proteins contributing to resistance to C. partellus . Results The multivariate analysis on a total of 967 proteins led to the identification of proteins correlating with insect resistance/susceptibility of S. bicolor . Upon C. partellus infe...
Uraria picta is a medicinally important ‘dashmula’ plant found in dry grasslands of India and is ... more Uraria picta is a medicinally important ‘dashmula’ plant found in dry grasslands of India and is facing overexploitation in wilds. Its roots have been used in traditional treatments while in modern medicine it is known to promote osteogenesis and possess anti-cancer properties. Rhizobium rhizogenes ATCC-15834 was used to induce hairy roots (HR) in in vitro raised U. picta seedlings. This is the first report of U. picta HR induction and characterization. The comparative biochemical and functional analysis showed that U. picta true roots (TR) and HR extracts display high free radical scavenging activity (~ 84%) and higher cytotoxic activity in cancer cell lines HeLa (71.18%) and MCF-7 (89.36%) as compared to the normal cell line HEK (58.87%). There was a twofold increase in HR biomass upon jasmonic acid (JA) treatment, while salicylic acid (SA) and abscisic acid (ABA) had no significant effects, though ABA led to increase in the HR thickness. In comparative metabolomics HR-LC/MS study, 39% metabolites were commonly detected in TR, HR and Hairy root exudates (HREx). Major chemical classes of the metabolites detected were lipids, benzenoids and organic acids represented by glutinone; estra-1,3,5(10)-triene-3,6 beta, 17 beta-triol triacetate; azokisaponin III; gingerol, shogaol and mucronine B with well-known therapeutic potentials. Additionally, a high proportion of unknown masses were also found in U. picta TR, HR and HREx, which needs further investigation. Due to the parallels in the biochemical, metabolomic and functional aspects of TR and HR, U. picta HR represents a sustainable alternative source of U. picta bioactives. Comparative metabolomics reveals similarities in the hairy roots and true roots of Uraria picta, making it a suitable biotechnological alternative for biosynthesis of specialized metabolites.
The inert and surface tunable nature of silica nanoparticles (SiNPs) makes them suitable for diff... more The inert and surface tunable nature of silica nanoparticles (SiNPs) makes them suitable for different applications. We have evaluated the potential of SiNPs for delivering proteins in tomato (Lycopersicon esculentum) plants. SiNPs of 20 and 100 nm (Si20 and Si100) were functionalized with (3-aminopropyl) triethoxysilane (APTES) to obtain Si20APT and Si100APT, respectively, that were non-toxic toward plants. The functionalized nanoparticles were taken up by plants through roots as well as leaf surfaces. They were seen to be localized near the vasculature, particularly around the xylem. Si20APT and Si100APT nanoparticles were conjugated with soybean trypsin inhibitor (STI) to yield Si20APT-STI and Si100APT-STI, respectively. Based on the trypsin inhibitory activity of loaded nanoparticles, optimum loading was obtained for 0.4 mg of STI per 0.8 mg of NPs. Si20APT nanoparticles retained higher contents of STI than Si100APT. Exposure of STI-conjugated nanoparticles to 25°C or pH 8.0 aided release of the inhibitor. The particle bound STI inhibited bovine trypsin by 80% and Helicoverpa armigera gut proteinase (HGP) activity by 50%. Second instar H. armigera larvae ingesting STI-loaded particles (incorporated in artificial diet or leaves) showed significant retardation in growth. In choice assays, Si20APT-STI applied leaf discs were strikingly avoided by insect larvae. On the basis of the results obtained in this investigation, we recommend the use of Si20 nanoparticles for developing plant delivery vehicles in the future.
ABSTRACTPhylogenetic diversity of culturable actinobacteria isolated from the intertidal regions ... more ABSTRACTPhylogenetic diversity of culturable actinobacteria isolated from the intertidal regions of west coast of Maharashtra, India was studied using 16S rRNA gene sequencing. Total of 140 actinobacterial isolates were obtained, which belonged to 14 genera, 10 families and 65 putative species with Streptomyces being the most dominant (63%) genus followed by Nocardiopsis and Micromonospora. They were screened for production of extracellular protease inhibitors (PI) against three pure proteases viz. chymotrypsin, trypsin, subtilisin and one crude extracellular protease from Pseudomonas aeruginosa. Eighty percent of the isolates showed PI activity against at least one of the four proteases, majority of them belonged to genus Streptomyes. Actinobacterial diversity from two sites Ade (17°52′ N, 73°04′ E) and Harnai (17°48′ N, 73°05′ E) with varying degree of anthropological pressure showed that more putative species diversity was obtained from site with lower human intervention i.e Ade ...
Phylogenetic diversity of cultivable actinobacteria isolated from sponges and associated environm... more Phylogenetic diversity of cultivable actinobacteria isolated from sponges and associated environments of intertidal zones, along the northern parts of west coast of India, were studied using 16S rRNA gene sequences. A subset of actinobacteria were screened for three activities, namely predatory behavior, antibacterial activity and enzyme inhibition. We recovered 207 isolates of actinobacteria belonging to 16 families and 25 genera, which could be attributed to 55 putative species using Poisson Tree Processes and 60 putative species based on Bayesian Poisson Tree Processes. Although the trends in the discovery of actinobacterial genera isolated from sponges was consistent with previous studies from different study areas, we provide first report of six actinobacterial species from sponges. We observed widespread non-obligate epibiotic predatory behavior in eight actinobacterial genera and we provide first report of predatory activity in Brevibacterium, Glutamicibacter, Micromonospora,...
Thionins are small, cysteine‐rich peptides that play an important role in plant defense, primaril... more Thionins are small, cysteine‐rich peptides that play an important role in plant defense, primarily through their interactions with membranes. Eight novel γ‐thionin peptides (CanThio1‐8) were isolated from the flower of Capsicum annuum. Sequence analysis revealed that the peptides cluster into three groups. A representative peptide from each group (CanThio1, 2, and 3) was used for experimental characterization. Interestingly, peptides were found to possess some cytotoxic activity against normal human embryonic kidney cell line but higher cytotoxicity against cancer cell line MCF‐7. CanThio3 peptide was chosen as a representative peptide to study the molecular mechanism of action on membranes. Microsecond timescale atomistic simulations of CanThio3 were performed in the presence of a POPC (1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine) lipid bilayer. Simulations revealed that CanThio3 interacts with the bilayer and causes lipid thinning in the vicinity. Nonpolar amino acids specific to the α‐core region of CanThio3 along with nonpolar residues in the γ‐core region are seen to interact with the lipid tails. The differences in the amino acid sequence of CanThio peptides in these regions explain the variability in cytotoxic activities. In summary, our results demonstrate the membrane‐mediated activity of a novel series of γ‐thionin peptides from C. annuum.
Oroxylum indicum (L.) Kurz is a medicinally important and rare tree species of the family Bignoni... more Oroxylum indicum (L.) Kurz is a medicinally important and rare tree species of the family Bignoniaceae. It is rich in flavonoid content and its mature roots are extensively used in Ayurvedic formulations. O. indicum specific flavonoids like oroxylin B, prunetin and oroxindin possess antibacterial, antiproliferative, antioxidant and anticancerous properties, signifying its importance in modern medicine. In the present study, de novo transcriptome analysis of O. indicum root was performed to elucidate the genes involved in flavonoid metabolism. A total of 24,625,398 high quality reads were assembled into 121,286 transcripts with N50 value 1783. The BLASTx search of 81,002 clustered transcripts against Viridiplantae Uniprot database led to annotation of 46,517 transcripts. Furthermore, Gene ontology (GO) revealed that 34,231 transcripts mapped to 3049 GO terms and KEGG analysis demonstrated that 4570 transcripts plausibly involved in 132 biosynthetic pathways. The transcriptome data indicated that cinnamyl-alcohol dehydrogenase (OinCAD) was abundant in phenylpropanoid pathway genes while; naringenin chalcone synthase (OinCHS), flavone synthase (OinFNS) and flavonoid 3', 5'-methyltransferase (OinF35 MT) were abundant in flavonoid, isoflavonoid, flavone and flavonol biosynthesis pathways, respectively. Transcription factor analysis demonstrated the abundance of MYB, bHLH and WD40 transcription factor families, which regulate the flavonoid biosynthesis. Flavonoid pathway genes displayed differential expression in young and old roots of O. indicum. The transcriptome led to the identification of 31 diverse full length Cytochrome P450 (CYP450) genes which may be involved in biosynthesis of specialized metabolites and flavonoids like baicalein and baicalin. Thus, the information obtained in this study will be a valuable tool for identifying genes and developing system biology approaches for in vitro synthesis of specialized O. indicum metabolites.
The present invention relates to a method for pest management using inhibitory repeat domain IRD ... more The present invention relates to a method for pest management using inhibitory repeat domain IRD 9 (Seq ID No.2) proteinase inhibitor showing enhanced inhibitory activity against the gut proteases of insects. More particularly, the present invention relates to a IRD 9 (Seq ID No.2) proteinase inhibitor from non-host plant Capsicum annuum, which possesses significantly high insect protease inhibition activity against the gut proteases of Helicoverpa armigera.
Helicoverpa armigera (Lepidoptera: Noctuidae) and other polyphagous agricultural pests are extend... more Helicoverpa armigera (Lepidoptera: Noctuidae) and other polyphagous agricultural pests are extending their plant host range and emerging as serious agents in restraining crop productivity. Dynamic regulation, coupled with a diversity of digestive and detoxifying enzymes, play a crucial role in the adaptation of polyphagous insects. To investigate the functional intricacy of serine proteases in the development and polyphagy of H. armigera, we profiled the expression of eight trypsin-like and four chymotrypsin-like phylogenetically diverse mRNAs from different life stages of H. armigera reared on nutritionally distinct host plants. These analyses revealed diet- and stage-specific protease expression patterns. The trypsins expressed showed structural variations, which might result in differential substrate specificity and interaction with inhibitors. Protease profiles in the presence of inhibitors and their mass spectrometric analyses revealed insight into their differential activity. These findings emphasize the differential expression of serine proteases and their consequences for digestive physiology in promoting polyphagy in H. armigera.
Biochimica et Biophysica Acta (BBA) - General Subjects, 2013
A multi-domain Pin-II type protease inhibitor from Capsicum annuum (CanPI-7) is known to be effec... more A multi-domain Pin-II type protease inhibitor from Capsicum annuum (CanPI-7) is known to be effective against the insect pest, Helicoverpa armigera. The present study is an attempt to investigate the optimal dose of recombinant CanPI-7 (rCanPI-7) for effective antibiosis to H. armigera and further to characterize the responses of digestive proteases upon rCanPI-7 ingestion. The gut protease activity was assessed biochemically and transcript accumulation pattern for selected trypsin and chymotrypsin genes was analyzed by quantitative Real-Time PCR. The growth retardation upon exposure to rCanPI-7 was more prominent in neonates as compared to third instar larvae. Influence of stage and dosage of rCanPI-7 was conspicuous on the expression and regulation of candidate trypsin and chymotrypsin genes in H. armigera. The transcript accumulation pattern correlated with the protease activity in rCanPI-7 exposed larvae. We conclude that early exposure and specific dose of protease inhibitor are essential for effective antibiosis despite the large diversity and plasticity in the expression of protease genes in H. armigera. Moreover, it is also evident that the regulation and expression of H. armigera gut proteases are specific to the stage of PI exposure. These results highlight the requirement of optimal PI concentration for effective growth retardation and for inhibiting the major gut proteases of H. armigera.
Capsicum annuum (L.) expresses diverse potato type II family proteinase inhibitors comprising of ... more Capsicum annuum (L.) expresses diverse potato type II family proteinase inhibitors comprising of inhibitory repeat domain (IRD) as basic functional unit. Most IRDs contain eight conserved cysteines forming four disulfide bonds, which are indispensible for their stability and activity. We investigated the functional significance of evolutionary variations in IRDs and their role in mediating interaction between the inhibitor and cognate proteinase. Among the 18 IRDs encoded by C. annuum, IRD-7, -9, and -12 were selected for further characterization on the basis of variation in their reactive site loop, number of conserved cysteine residues, and higher theoretical ΔGbind for interaction with Helicoverpa armigera trypsin. Moreover, inhibition kinetics showed that IRD-9, despite loss of some of the disulfide bonds, was a more potent proteinase inhibitor among the three selected IRDs. Molecular dynamic simulations revealed that serine residues in the place of cysteines at seventh and eighth positions of IRD-9 resulted in an increase in the density of intramolecular hydrogen bonds and reactive site loop flexibility. Results of the serine residues chemical modification also supported this observation and provided a possible explanation for the remarkable inhibitory potential of IRD-9. Furthermore, this natural variant among IRDs showed special attributes like stability to proteolysis and synergistic inhibitory effect on other IRDs. It is likely that IRDs have coevolved selective specialization of their structure and function as a response towards specific insect proteases they encountered. Understanding the molecular mechanism of pest protease-plant proteinaceous inhibitor interaction will help in developing effective pest control strategies. An animated interactive 3D complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:39.
F il I n s Helicoverpa armigera: Ecology and Control Using Novel Biotechnological Approaches Va... more F il I n s Helicoverpa armigera: Ecology and Control Using Novel Biotechnological Approaches Vaijayanti A. Tamhane Ashok P. Giri Vidya S. Gupta Plant Molecular Biology Unit, Division of Biochemical ... 7. Wilkins, TA; Rajasekaran, K.; Anderson, DM Cotton biotechnology. Crit. ...
Background Spotted stem borer- Chilo partellus - a Lepidopteran insect pest of Sorghum bicolor is... more Background Spotted stem borer- Chilo partellus - a Lepidopteran insect pest of Sorghum bicolor is responsible for major economic losses. It is an oligophagous pest, which bores through the plant stem, causing ‘deadheart’ and hampering the development of the main cob. We applied a label-free quantitative proteomics approach on three genotypes of S. bicolor with differential resistance/ susceptibility to insect pests, intending to identify the S. bicolor’s systemic protein complement contributing to C. partellus tolerance. Methods The proteomes of S. bicolor with variable resistance to insect pests, ICSV700, IS2205 (resistant) and Swarna (susceptible) were investigated and compared using label-free quantitative proteomics to identify putative leaf proteins contributing to resistance to C. partellus . Results The multivariate analysis on a total of 967 proteins led to the identification of proteins correlating with insect resistance/susceptibility of S. bicolor . Upon C. partellus infe...
Uploads
Papers by vaijayanti tamhane