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Lu HB, Lu JB, Li LL, Zhang ZL, Chen JP, Li JM, Zhang CX, Huang HJ. Functional analysis of neutral lipases in bug feeding and reproduction. PEST MANAGEMENT SCIENCE 2023; 79:4809-4818. [PMID: 37483070 DOI: 10.1002/ps.7676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/13/2023] [Accepted: 07/22/2023] [Indexed: 07/25/2023]
Abstract
BACKGROUND The bean bug, Riptortus pedestris, is known to cause significant economic losses in soybean crops due to its seed-sucking behavior, but the mechanism of its adaptation to lipid-rich seeds remains poorly understood. To exploit potential target genes for controlling this pest, neutral lipases are functionally characterized in this study. RESULTS In this study, a total of 69 lipases were identified in R. pedestris, including 35 neutral lipases that underwent significant expansion. The phylogeny, expression patterns, and catalytic capacity of neutral lipases were investigated and we selected six salivary gland-specific, eight gut-specific, and three ovary-specific genes for functional analysis. All three ovary-specific neutral lipases (Chr1.3195, Chr1.0994, and Chr5.0087) are critical for insect reproduction, while a few gut-specific neutral lipases (Chr4.0221 and Chr1.3207) influence insect survivorship or weight gain. In contrast, no significant phenotype change is observed when silencing salivary gland-specific neutral lipases. CONCLUSION The lipases Chr1.3195, Chr1.0994, Chr5.0087, Chr4.0221, and Chr1.3207 are essential for R. pedestris feeding and reproduction, and the insect is highly sensitive to their deficiency, suggesting that neutral lipases are promising candidates for application in RNAi-based control of this destructive pest. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Hai-Bin Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Jia-Bao Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Li-Li Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Ze-Long Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Jian-Ping Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Jun-Min Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Chuan-Xi Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China
| | - Hai-Jian Huang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of Ministry of Agriculture and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China
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Lazarević J, Milanović S, Šešlija Jovanović D, Janković-Tomanić M. Temperature- and Diet-Induced Plasticity of Growth and Digestive Enzymes Activity in Spongy Moth Larvae. Biomolecules 2023; 13:biom13050821. [PMID: 37238690 DOI: 10.3390/biom13050821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/04/2023] [Accepted: 05/06/2023] [Indexed: 05/28/2023] Open
Abstract
Temperature and food quality are the most important environmental factors determining the performance of herbivorous insects. The objective of our study was to evaluate the responses of the spongy moth (formerly known as the gypsy moth) [Lymantria dispar L. (Lepidoptera: Erebidae)] to simultaneous variation in these two factors. From hatching to the fourth instar, larvae were exposed to three temperatures (19 °C, 23 °C, and 28 °C) and fed four artificial diets that differed in protein (P) and carbohydrate (C) content. Within each temperature regime, the effects of the nutrient content (P+C) and ratio (P:C) on development duration, larval mass, growth rate, and activities of digestive proteases, carbohydrases, and lipase were examined. It was found that temperature and food quality had a significant effect on the fitness-related traits and digestive physiology of the larvae. The greatest mass and highest growth rate were obtained at 28 °C on a high-protein low-carbohydrate diet. A homeostatic increase in activity was observed for total protease, trypsin, and amylase in response to low substrate levels in the diet. A significant modulation of overall enzyme activities in response to 28 °C was detected only with a low diet quality. A decrease in the nutrient content and P:C ratio only affected the coordination of enzyme activities at 28 °C, as indicated by the significantly altered correlation matrices. Multiple linear regression analysis showed that variation in fitness traits in response to different rearing conditions could be explained by variation in digestion. Our results contribute to the understanding of the role of digestive enzymes in post-ingestive nutrient balancing.
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Affiliation(s)
- Jelica Lazarević
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
| | - Slobodan Milanović
- Faculty of Forestry, University of Belgrade, Kneza Višeslava 1, 11030 Belgrade, Serbia
- Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemĕdĕlská 3, 613 00 Brno, Czech Republic
| | - Darka Šešlija Jovanović
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
| | - Milena Janković-Tomanić
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia
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An E3 Ubiquitin Ligase Scaffolding Protein Is Proviral during Chikungunya Virus Infection in Aedes aegypti. Microbiol Spectr 2022; 10:e0059522. [PMID: 35435754 PMCID: PMC9241663 DOI: 10.1128/spectrum.00595-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Chikungunya virus (CHIKV) is a reemerging alphavirus causing chikungunya disease (CHIKD) and is transmitted to humans by Aedes mosquitoes. The virus establishes an intricate balance of cellular interactions that ultimately helps in its replication and dodges cellular immune response. In an attempt to identify cellular host factors required during CHIKV replication in Aag2 cells, we performed global transcriptomics of CHIKV-infected Aag2 cells, and further, we compared this library with the Drosophila RNAi Screening Center (DRSC) database and identified transcripts that were regulated in Aedes aegypti during CHIKV infection. These analyses revealed specific pathways, such as ubiquitin-related pathways, proteolysis pathways, protein catabolic processes, protein modification, and cellular protein metabolic processes, involved during replication of the virus. Loss-of-function assays of selected candidates revealed their proviral or antiviral characteristics upon CHIKV infection in A. aegypti-derived Aag2 cells. Further validations identified that the ubiquitin proteasomal pathway is required for CHIKV infection in A. aegypti and that an important member of this family of proteins, namely, AeCullin-3 (Aedes ortholog of human cullin-3), is a proviral host factor of CHIKV replication in Aag2 cells. IMPORTANCE Arboviruses cause several diseases in humans and livestock. Vector control is the main strategy for controlling diseases transmitted by mosquitoes. In this context, it becomes paramount to understand how the viruses replicate in the vector for designing better transmission blocking strategies. We obtained the global transcriptome signature of A. aegypti cells during CHIKV infection, and in order to obtain the maximum information from these data sets, we further utilized the well-characterized Drosophila system and arrived upon a set of transcripts and their pathways that affect A. aegypti cells during CHIKV infection. These analyses and further validations reveal that important pathways related to protein degradation are actively involved during CHIKV infection in A. aegypti and are mainly proviral. Targeting these molecules may provide novel approaches for blocking CHIKV replication in A. aegypti.
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Thrimawithana AH, Wu C, Christeller JT, Simpson RM, Hilario E, Tooman LK, Begum D, Jordan MD, Crowhurst R, Newcomb RD, Grapputo A. The Genomics and Population Genomics of the Light Brown Apple Moth, Epiphyas postvittana, an Invasive Tortricid Pest of Horticulture. INSECTS 2022; 13:insects13030264. [PMID: 35323562 PMCID: PMC8951345 DOI: 10.3390/insects13030264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/01/2022] [Accepted: 03/04/2022] [Indexed: 12/13/2022]
Abstract
Simple Summary In this study, we produced a genomic resource for the light brown apple moth, Epiphyas postvittana, to understand the biological basis of adaptation to a high number of hosts (polyphagy) and the invasive nature of this and other lepidopteran pests. The light brown apple moth is an invasive pest of horticultural plants, with over 500 recorded plant hosts. With origins in Australia, the pest has subsequently spread to New Zealand, Hawaii, California and Europe, causing significant economic losses for fruit producers. Comparative genomic analyses with other lepidopteran genomes indicate that a high proportion of the genome is made up of repetitive sequences, with the majority of the known elements being DNA transposable elements and retrotransposons. Twenty gene families show significant expansions, including some likely to have a role in its pest status. Finally, population genomics, investigated by a RAD-tag approach, indicated likely patterns of invasion and admixture, with Californian moths most probably being derived from Australia. Abstract The light brown apple moth, Epiphyas postvittana is an invasive, polyphagous pest of horticultural systems around the world. With origins in Australia, the pest has subsequently spread to New Zealand, Hawaii, California and Europe, where it has been found on over 500 plants, including many horticultural crops. We have produced a genomic resource, to understand the biological basis of the polyphagous and invasive nature of this and other lepidopteran pests. The assembled genome sequence encompassed 598 Mb and has an N50 of 301.17 kb, with a BUSCO completion rate of 97.9%. Epiphyas postvittana has 34% of its assembled genome represented as repetitive sequences, with the majority of the known elements made up of longer DNA transposable elements (14.07 Mb) and retrotransposons (LINE 17.83 Mb). Of the 31,389 predicted genes, 28,714 (91.5%) were assigned to 11,438 orthogroups across the Lepidoptera, of which 945 were specific to E. postvittana. Twenty gene families showed significant expansions in E. postvittana, including some likely to have a role in its pest status, such as cytochrome p450s, glutathione-S-transferases and UDP-glucuronosyltransferases. Finally, using a RAD-tag approach, we investigated the population genomics of this pest, looking at its likely patterns of invasion.
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Affiliation(s)
- Amali H. Thrimawithana
- The New Zealand Institute of Plant and Food Research Limited, Auckland 1025, New Zealand; (A.H.T.); (C.W.); (E.H.); (L.K.T.); (D.B.); (M.D.J.); (R.C.)
| | - Chen Wu
- The New Zealand Institute of Plant and Food Research Limited, Auckland 1025, New Zealand; (A.H.T.); (C.W.); (E.H.); (L.K.T.); (D.B.); (M.D.J.); (R.C.)
| | - John T. Christeller
- The New Zealand Institute of Plant and Food Research Limited, Palmerston North 4410, New Zealand; (J.T.C.); (R.M.S.)
| | - Robert M. Simpson
- The New Zealand Institute of Plant and Food Research Limited, Palmerston North 4410, New Zealand; (J.T.C.); (R.M.S.)
| | - Elena Hilario
- The New Zealand Institute of Plant and Food Research Limited, Auckland 1025, New Zealand; (A.H.T.); (C.W.); (E.H.); (L.K.T.); (D.B.); (M.D.J.); (R.C.)
| | - Leah K. Tooman
- The New Zealand Institute of Plant and Food Research Limited, Auckland 1025, New Zealand; (A.H.T.); (C.W.); (E.H.); (L.K.T.); (D.B.); (M.D.J.); (R.C.)
| | - Doreen Begum
- The New Zealand Institute of Plant and Food Research Limited, Auckland 1025, New Zealand; (A.H.T.); (C.W.); (E.H.); (L.K.T.); (D.B.); (M.D.J.); (R.C.)
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Melissa D. Jordan
- The New Zealand Institute of Plant and Food Research Limited, Auckland 1025, New Zealand; (A.H.T.); (C.W.); (E.H.); (L.K.T.); (D.B.); (M.D.J.); (R.C.)
| | - Ross Crowhurst
- The New Zealand Institute of Plant and Food Research Limited, Auckland 1025, New Zealand; (A.H.T.); (C.W.); (E.H.); (L.K.T.); (D.B.); (M.D.J.); (R.C.)
| | - Richard D. Newcomb
- The New Zealand Institute of Plant and Food Research Limited, Auckland 1025, New Zealand; (A.H.T.); (C.W.); (E.H.); (L.K.T.); (D.B.); (M.D.J.); (R.C.)
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
- Correspondence:
| | - Alessandro Grapputo
- Dipartimento di Biologia, Università degli Studi di Padova, 35131 Padova, Italy;
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Barroso IG, Cardoso C, Ferreira C, Terra WR. Transcriptomic and proteomic analysis of the underlying mechanisms of digestion of triacylglycerols and phosphatides and absorption and fate of fatty acids along the midgut of Musca domestica. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2021; 39:100826. [PMID: 33839527 DOI: 10.1016/j.cbd.2021.100826] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 03/23/2021] [Accepted: 03/23/2021] [Indexed: 11/24/2022]
Abstract
Most dietary lipids are triacylglycerols (TAGs) and phosphatides that are digested by TAG lipases and phospholipases (PLIPs), respectively, originating fatty acids (FA). The genome of Musca domestica has genes coding for phospholipases A1 (1PLIP), A2 (2PLIP), B (BPLIP), and acid lipases (ALIP), as for proteins involved in activation, binding, and metabolism of FA, which expression in the larval midgut was evaluated by RNA-seq. Some of the codified proteins were identified in midgut microvillar-enriched membrane by proteomics. 1PLIPs are the most expressed PLIPs, mainly in anterior midgut whereas 2PLIPs, and BPLIP in middle and posterior midgut, and ALIPs between middle and posterior regions. Absorption of FAs is putatively accomplished by proteins involved in FA activation (acyl-CoA synthetases) found in microvillar-enriched membrane preparations. Furthermore, FA uptake could be enhanced by proteins that bind FAs (FA-binding proteins) and its activated form (acyl-CoA binding proteins) mainly expressed in posterior midgut. Activated FAs could have different fates: synthesis of diacylglycerol (DAG) and TAG through monoacylglycerol and glycerol-3-phosphate pathways; synthesis of phosphatides; energy source by β-oxidation. Most genes coding for enzymes of those routes is expressed mainly at the end of posterior midgut. Data suggest that phosphatides are digested in anterior midgut by Md1PLIPs, releasing lysophosphatides that emulsify fats to be digested by MdALIPs in the middle and posterior midgut. Most resulting FAs is absorbed in the posterior midgut, where they follow the synthesis of DAG, TAG, and phosphatides or are oxidized along the midgut, mainly in highly metabolic middle and posterior midgut regions.
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Affiliation(s)
- Ignacio G Barroso
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, Brazil
| | - Christiane Cardoso
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, Brazil
| | - Clelia Ferreira
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, Brazil
| | - Walter R Terra
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, Brazil.
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Sahaka M, Amara S, Wattanakul J, Gedi MA, Aldai N, Parsiegla G, Lecomte J, Christeller JT, Gray D, Gontero B, Villeneuve P, Carrière F. The digestion of galactolipids and its ubiquitous function in Nature for the uptake of the essential α-linolenic acid. Food Funct 2020; 11:6710-6744. [PMID: 32687132 DOI: 10.1039/d0fo01040e] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Galactolipids, mainly monogalactosyl diglycerides and digalactosyl diglycerides are the main lipids found in the membranes of plants, algae and photosynthetic microorganisms like microalgae and cyanobacteria. As such, they are the main lipids present at the surface of earth. They may represent up to 80% of the fatty acid stocks, including a large proportion of polyunsaturated fatty acids mainly α-linolenic acid (ALA). Nevertheless, the interest in these lipids for nutrition and other applications remains overlooked, probably because they are dispersed in the biomass and are not as easy to extract as vegetable oils from oleaginous fruit and oil seeds. Another reason is that galactolipids only represent a small fraction of the acylglycerolipids present in modern human diet. In herbivores such as horses, fish and folivorous insects, galactolipids may however represent the main source of dietary fatty acids due to their dietary habits and digestion physiology. The development of galactolipase assays has led to the identification and characterization of the enzymes involved in the digestion of galactolipids in the gastrointestinal tract, as well as by microorganisms. Pancreatic lipase-related protein 2 (PLRP2) has been identified as an important factor of galactolipid digestion in humans, together with pancreatic carboxyl ester hydrolase (CEH). The levels of PLRP2 are particularly high in monogastric herbivores thus highlighting the peculiar role of PLRP2 in the digestion of plant lipids. Similarly, pancreatic lipase homologs are found to be expressed in the midgut of folivorous insects, in which a high galactolipase activity can be measured. In fish, however, CEH is the main galactolipase involved. This review discusses the origins and fatty acid composition of galactolipids and the physiological contribution of galactolipid digestion in various species. This overlooked aspect of lipid digestion ensures not only the intake of ALA from its main natural source, but also the main lipid source of energy for growth of some herbivorous species.
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Affiliation(s)
- Moulay Sahaka
- Aix Marseille Univ, CNRS, UMR7281 Bioénergétique et Ingénierie des Protéines, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
| | - Sawsan Amara
- Lipolytech, Zone Luminy Biotech, 163 avenue de Luminy, 13288 Marseille Cedex 09, France
| | - Jutarat Wattanakul
- Division of Food, Nutrition and Dietetics, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK
| | - Mohamed A Gedi
- Division of Food, Nutrition and Dietetics, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK
| | - Noelia Aldai
- Lactiker Research Group, Department of Pharmacy & Food Sciences, University of the Basque Country (UPV/EHU), 01006 Vitoria-Gasteiz, Spain
| | - Goetz Parsiegla
- Aix Marseille Univ, CNRS, UMR7281 Bioénergétique et Ingénierie des Protéines, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
| | | | - John T Christeller
- The New Zealand Institute for Plant and Food Research Ltd (Plant & Food Research), Palmerston North Research Centre, Palmerston North, New Zealand
| | - David Gray
- Division of Food, Nutrition and Dietetics, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK
| | - Brigitte Gontero
- Aix Marseille Univ, CNRS, UMR7281 Bioénergétique et Ingénierie des Protéines, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
| | | | - Frédéric Carrière
- Aix Marseille Univ, CNRS, UMR7281 Bioénergétique et Ingénierie des Protéines, 31 Chemin Joseph Aiguier, 13009 Marseille, France.
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Comparative sialotranscriptome analysis of the rare Chinese cicada Subpsaltria yangi, with identification of candidate genes related to host-plant adaptation. Int J Biol Macromol 2019; 130:323-332. [PMID: 30807802 DOI: 10.1016/j.ijbiomac.2019.02.132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/22/2019] [Accepted: 02/22/2019] [Indexed: 01/01/2023]
Abstract
Little is known about the mechanisms underlying the relationship between changes in salivary proteins and the adaptation of insects to different host-plants. To address this knowledge gap, the transcriptional profiles of salivary glands were compared among three populations of the rare cicada Subpsaltria yangi, in which two populations specialize on Zizyphus jujuba var. spinosa, but the population occurring in the Helan (HL) Mountains is locally specialized on the endemic plant Ephedra lepidosperma. The comparisons indicate that genes related to digestion and detoxification are differentially regulated in populations feeding on different plants, possibly reflecting adaptative changes in salivary proteins of S. yangi in response to different host chemistries. In detail, 38 differentially expressed genes and 21 up-regulated genes related to digestion and detoxification were identified respectively in two pairwise comparisons among the populations using different hosts, with some genes exclusively expressed in the HL population. Our results are consistent with the hypothesis that the host plant shift in the HL population was facilitated by differential regulation of genes related to digestion and detoxification. This study provides new information for elucidating the molecular mechanisms underlying the relationship between changed salivary proteins and the adaptability of plant-feeding insects to novel host plants.
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Pearce SL, Clarke DF, East PD, Elfekih S, Gordon KHJ, Jermiin LS, McGaughran A, Oakeshott JG, Papanicolaou A, Perera OP, Rane RV, Richards S, Tay WT, Walsh TK, Anderson A, Anderson CJ, Asgari S, Board PG, Bretschneider A, Campbell PM, Chertemps T, Christeller JT, Coppin CW, Downes SJ, Duan G, Farnsworth CA, Good RT, Han LB, Han YC, Hatje K, Horne I, Huang YP, Hughes DST, Jacquin-Joly E, James W, Jhangiani S, Kollmar M, Kuwar SS, Li S, Liu NY, Maibeche MT, Miller JR, Montagne N, Perry T, Qu J, Song SV, Sutton GG, Vogel H, Walenz BP, Xu W, Zhang HJ, Zou Z, Batterham P, Edwards OR, Feyereisen R, Gibbs RA, Heckel DG, McGrath A, Robin C, Scherer SE, Worley KC, Wu YD. Genomic innovations, transcriptional plasticity and gene loss underlying the evolution and divergence of two highly polyphagous and invasive Helicoverpa pest species. BMC Biol 2017; 15:63. [PMID: 28756777 PMCID: PMC5535293 DOI: 10.1186/s12915-017-0402-6] [Citation(s) in RCA: 185] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/04/2017] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Helicoverpa armigera and Helicoverpa zea are major caterpillar pests of Old and New World agriculture, respectively. Both, particularly H. armigera, are extremely polyphagous, and H. armigera has developed resistance to many insecticides. Here we use comparative genomics, transcriptomics and resequencing to elucidate the genetic basis for their properties as pests. RESULTS We find that, prior to their divergence about 1.5 Mya, the H. armigera/H. zea lineage had accumulated up to more than 100 more members of specific detoxification and digestion gene families and more than 100 extra gustatory receptor genes, compared to other lepidopterans with narrower host ranges. The two genomes remain very similar in gene content and order, but H. armigera is more polymorphic overall, and H. zea has lost several detoxification genes, as well as about 50 gustatory receptor genes. It also lacks certain genes and alleles conferring insecticide resistance found in H. armigera. Non-synonymous sites in the expanded gene families above are rapidly diverging, both between paralogues and between orthologues in the two species. Whole genome transcriptomic analyses of H. armigera larvae show widely divergent responses to different host plants, including responses among many of the duplicated detoxification and digestion genes. CONCLUSIONS The extreme polyphagy of the two heliothines is associated with extensive amplification and neofunctionalisation of genes involved in host finding and use, coupled with versatile transcriptional responses on different hosts. H. armigera's invasion of the Americas in recent years means that hybridisation could generate populations that are both locally adapted and insecticide resistant.
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Affiliation(s)
- S L Pearce
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - D F Clarke
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- School of Biological Sciences, University of Melbourne, Parkville, Vic, Australia
| | - P D East
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - S Elfekih
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - K H J Gordon
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia.
| | - L S Jermiin
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - A McGaughran
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - J G Oakeshott
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia.
| | - A Papanicolaou
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- Hawksbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - O P Perera
- Southern Insect Management Research Unit, USDA-ARS, Stoneville, MS, USA
| | - R V Rane
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- School of Biological Sciences, University of Melbourne, Parkville, Vic, Australia
| | - S Richards
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA.
| | - W T Tay
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - T K Walsh
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - A Anderson
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - C J Anderson
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- Biological and Environmental Sciences, University of Stirling, Stirling, UK
| | - S Asgari
- School of Biological Sciences, University of Queensland, Brisbane St Lucia, QLD, Australia
| | - P G Board
- John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | | | - P M Campbell
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - T Chertemps
- Sorbonnes Universités, UPMC Université Paris 06, Institute of Ecology and Environmental Sciences of Paris, Paris, France
- National Institute for Agricultural Research (INRA), Institute of Ecology and Environmental Sciences of Paris, Versailles, France
| | | | - C W Coppin
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | | | - G Duan
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - C A Farnsworth
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - R T Good
- School of Biological Sciences, University of Melbourne, Parkville, Vic, Australia
| | - L B Han
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Y C Han
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - K Hatje
- Max Planck Institute for Biophysical Chemistry, Gottingen, Germany
| | - I Horne
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - Y P Huang
- Institute of Plant Physiology and Ecology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - D S T Hughes
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - E Jacquin-Joly
- National Institute for Agricultural Research (INRA), Institute of Ecology and Environmental Sciences of Paris, Versailles, France
| | - W James
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - S Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - M Kollmar
- Max Planck Institute for Biophysical Chemistry, Gottingen, Germany
| | - S S Kuwar
- Max Planck Institute of Chemical Ecology, Jena, Germany
| | - S Li
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - N-Y Liu
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- Key Laboratory of Forest Disaster Warning and Control of Yunnan Province, Southwest Forestry University, Kunming, 650224, China
| | - M T Maibeche
- Sorbonnes Universités, UPMC Université Paris 06, Institute of Ecology and Environmental Sciences of Paris, Paris, France
- National Institute for Agricultural Research (INRA), Institute of Ecology and Environmental Sciences of Paris, Versailles, France
| | - J R Miller
- J. Craig Venter Institute, Rockville, MD, USA
| | - N Montagne
- Sorbonnes Universités, UPMC Université Paris 06, Institute of Ecology and Environmental Sciences of Paris, Paris, France
| | - T Perry
- School of Biological Sciences, University of Melbourne, Parkville, Vic, Australia
| | - J Qu
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - S V Song
- School of Biological Sciences, University of Melbourne, Parkville, Vic, Australia
| | - G G Sutton
- J. Craig Venter Institute, Rockville, MD, USA
| | - H Vogel
- Max Planck Institute of Chemical Ecology, Jena, Germany
| | - B P Walenz
- J. Craig Venter Institute, Rockville, MD, USA
| | - W Xu
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia
| | - H-J Zhang
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
- Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, Chongqing Medical University, Chongqing, 400016, China
| | - Z Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - P Batterham
- School of Biological Sciences, University of Melbourne, Parkville, Vic, Australia
| | | | - R Feyereisen
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej, Denmark
| | - R A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - D G Heckel
- Max Planck Institute of Chemical Ecology, Jena, Germany
| | - A McGrath
- CSIRO Black Mountain, GPO Box 1700, Canberra, ACT, 2600, Australia
| | - C Robin
- School of Biological Sciences, University of Melbourne, Parkville, Vic, Australia
| | - S E Scherer
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - K C Worley
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Y D Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu, China
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9
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Zhu YC, Yao J, Luttrell R. Identification of Genes Potentially Responsible for extra-Oral Digestion and Overcoming Plant Defense from Salivary Glands of the Tarnished Plant Bug (Hemiptera: Miridae) Using cDNA Sequencing. JOURNAL OF INSECT SCIENCE (ONLINE) 2016; 16:iew041. [PMID: 27324587 PMCID: PMC4913459 DOI: 10.1093/jisesa/iew041] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/12/2016] [Indexed: 05/14/2023]
Abstract
Saliva is known to play a crucial role in tarnished plant bug (TPB, Lygus lineolaris [Palisot de Beauvois]) feeding. By facilitating the piercing, the enzyme-rich saliva may be used for extra-oral digestion and for overcoming plant defense before the plant fluids are ingested by TPBs. To identify salivary gland genes, mRNA was extracted from salivary glands and cDNA library clones were sequenced. A de novo-assembling of 7,000 Sanger sequences revealed 666 high-quality unique cDNAs with an average size of 624 bp, in which the identities of 347 cDNAs were determined using Blast2GO. Kyoto Encyclopedia of Genes and Genomes analysis indicated that these genes participate in eighteen metabolic pathways. Identifications of large number of enzyme genes in TPB salivary glands evidenced functions for extra-oral digestion and feeding damage mechanism, including 45 polygalacturonase, two α- amylase, one glucosidase, one glycan enzyme, one aminopeptidase, four lipase, and many serine protease cDNAs. The presence of multiple transcripts, multigene members, and high abundance of cell wall degradation enzymes (polygalacturonases) indicated that the enzyme-rich saliva may cause damage to plants by breaking down plant cell walls to make nutrients available for feeding. We also identified genes potentially involved in insect adaptation and detoxifying xenobiotics that may allow insects to overcome plant defense responses, including four glutathione S-transferases, three esterases, one cytochrome P450, and several serine proteases. The gene profiles of TPB salivary glands revealed in this study provides a foundation for further understanding and potential development of novel enzymatic inhibitors, or other RNAi approaches that may interrupt or minimize TPB feeding damage.
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Affiliation(s)
- Yu-Cheng Zhu
- USDA-ARS Southern Insect Management Research Unit, Stoneville, MS 38776, USA
| | - Jianxiu Yao
- USDA-ARS Southern Insect Management Research Unit, Stoneville, MS 38776, USA
| | - Randall Luttrell
- USDA-ARS Southern Insect Management Research Unit, Stoneville, MS 38776, USA
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10
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Moczek AP. Developmental plasticity and evolution--quo vadis? Heredity (Edinb) 2015; 115:302-5. [PMID: 26374347 DOI: 10.1038/hdy.2015.14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 02/06/2023] Open
Abstract
The role of developmental (phenotypic) plasticity in ecology and evolution is receiving a growing appreciation among the biologists, and many plasticity-specific concepts have become well established as part of the mainstream evolutionary biological thinking. In this essay, I posit that despite this progress several key perspectives in developmental plasticity remain remarkably traditional, and that it may be time to re-evaluate their continued usefulness in the face of the available evidence as the field looks to its future. Specifically, I discuss the utility of viewing plastic development as ultimately rooted in genes and genomes, and investigate the common notion that the environment--albeit a critical source of information--nevertheless remains passive, external to and separable from the organism responding to it. I end by highlighting conceptual and empirical opportunities that may permit developmental plasticity research to transcend its current boundaries and to continue its contributions toward a holistic and realistic understanding of organismal development and evolution.
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Affiliation(s)
- A P Moczek
- Department of Biology, Indiana University, Bloomington, IN, USA
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11
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12
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Christeller JT, Galis I. α-linolenic acid concentration and not wounding per se is the key regulator of octadecanoid (oxylipin) pathway activity in rice (Oryza sativa L.) leaves. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 83:117-25. [PMID: 25129550 DOI: 10.1016/j.plaphy.2014.07.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 07/17/2014] [Indexed: 05/25/2023]
Abstract
Using an in vitro system composed of crushed leaf tissues to simulate the wounding response in rice leaves, we established that synthesis of jasmonic acid (JA) and jasmonic acid-isoleucine (JA-Ile) can only occur in unwounded tissue and, in wounded tissue, that only the chloroplast-located section of the octadecanoid pathway is active, resulting in the accumulation of 12-oxo-phytodienoic acid (OPDA). We further showed that OPDA accumulation in vitro was inhibited by 90% using the general lipase inhibitor, tetrahydrolipstatin, indicating that production of α-linolenic acid was the rate-limiting step in octadecanoid pathway activity in rice following wounding and the enzyme capacity for an active pathway was already present. We confirmed this result by showing that added α-linolenic acid stimulated OPDA synthesis in vitro and stimulated OPDA, JA and JA-Ile synthesis in vivo in unwounded tissue. Thus, the response to wounding can be mimicked by the provision of free α-linolenic acid. Our results draw attention to the key importance of lipase activity in initiation of JA and JA-Ile biosynthesis and our lack of knowledge of the cognate lipase(s), lipase substrate identity and mechanism(s) of activation in wounded and unwounded tissue.
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Affiliation(s)
- John T Christeller
- Institute of Plant Science and Resources, Okayama University, Chuo 2-10-1, Kurashiki, Okayama 710-0046, Japan.
| | - Ivan Galis
- Institute of Plant Science and Resources, Okayama University, Chuo 2-10-1, Kurashiki, Okayama 710-0046, Japan.
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13
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Christeller JT, McGhie TK, Poulton J, Markwick NP. Triterpene acids from apple peel inhibit lepidopteran larval midgut lipases and larval growth. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2014; 86:137-50. [PMID: 24753088 DOI: 10.1002/arch.21157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fruit extracts from apple, kiwifruit, feijoa, boysenberry, and blueberry were screened for the presence of lipase inhibitory compounds against lepidopteran larval midgut crude extracts. From 120 extracts, six showed significant inhibition with an extract from the peel of Malus × domestica cv. "Big Red" showing highest levels of inhibition. Because this sample was the only apple peel sample in the initial screen, a survey of peels from seven apple cultivars was undertaken and showed that, despite considerable variation, all had inhibitory activity. Successive solvent fractionation and LC-MS of cv. "Big Red" apple peel extract identified triterpene acids as the most important inhibitory compounds, of which ursolic acid and oleanolic acid were the major components and oxo- and hydroxyl-triterpene acids were minor components. When ursolic acid was incorporated into artificial diet and fed to Epiphyas postvittana Walker (Tortricidae: Lepidoptera) larvae at 0.16% w/v, a significant decrease in larval weight was observed after 21 days. This concentration of ursolic acid is less than half the concentration reported in the skin of some apple cultivars.
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Affiliation(s)
- John T Christeller
- The New Zealand Institute for Plant & Food Research, Palmerston North, New Zealand; Institute of Plant Sciences and Resources, Okayama University, Kurashiki, Okayama, Japan
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14
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Partial deletion of beta9 loop in pancreatic lipase-related protein 2 reduces enzyme activity with a larger effect on long acyl chain substrates. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1293-301. [PMID: 24046870 DOI: 10.1016/j.bbalip.2013.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Structural studies on pancreatic lipase have revealed a complex architecture of surface loops surrounding the enzyme active site and potentially involved in interactions with lipids. Two of them, the lid and beta loop, expose a large hydrophobic surface and are considered as acyl chain binding sites based on their interaction with an alkyl phosphonate inhibitor. While the role of the lid in substrate recognition and selectivity has been extensively studied, the implication of beta9 loop in acyl chain stabilization remained hypothetical. The characterization of an enzyme with a natural deletion of the lid, guinea pig pancreatic lipase-related protein 2 (GPLRP2), suggests however an essential contribution of the beta9 loop in the stabilization of the acyl enzyme intermediate formed during the lipolysis reaction. A GPLRP2 mutant with a seven-residue deletion of beta9 loop (GPLRP2-deltabeta9) was produced and its enzyme activity was measured using various substrates (triglycerides, monoglycerides, galactolipids, phospholipids, vinyl esters) with short, medium and long acyl chains. Whatever the substrate tested, GPLRP2-deltabeta9 activity is drastically reduced compared to that of wild-type GPLRP2 and this effect is more pronounced as the length of substrate acyl chain increases. Changes in relative substrate selectivity and stereoselectivity remained however weak. The deletion within beta9 loop has also a negative effect on the rate of enzyme inhibition by alkyl phosphonates. All these findings indicate that the reduced enzyme turnover observed with GPLRP2-deltabeta9 results from a weaker stabilization of the acyl enzyme intermediate due to a loss of hydrophobic interactions.
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McGhie TK, Hudault S, Lunken RCM, Christeller JT. Apple peels, from seven cultivars, have lipase-inhibitory activity and contain numerous ursenoic acids as identified by LC-ESI-QTOF-HRMS. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:482-91. [PMID: 22148752 DOI: 10.1021/jf203970j] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Apple peel contains numerous phytochemicals, many of which show bioactivity. This study investigated the identity of triterpenoid compounds contained in ethanolic extracts of peel from seven apple cultivars. Using HPLC-ESI-QTOF-HRMS, accurate mass information was obtained for 43 compounds, and chemical identity was inferred from the calculated elemental composition, fragment masses, ms/ms, and a limited set of authentic standards. Compounds were identified as triterpene acids and tentatively identified as ursenoic (or oleanoic) acid derivatives containing hydroxyl, oxo, and coumaroyloxy groups. These apple skin extracts exhibited lipase-inhibitory activity, which may be linked to the ursenoic acid content. Furthermore, both triterpene content and lipase-inhibitory activity varied by cultivar.
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Affiliation(s)
- Tony K McGhie
- The New Zealand Institute for Plant and Food Research Ltd, Private Bag 11600, Palmerston North 4442, New Zealand.
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16
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Markwick NP, Poulton J, McGhie TK, Wohlers MW, Christeller JT. The effects of the broad-specificity lipase inhibitor, tetrahydrolipstatin, on the growth, development and survival of the larvae of Epiphyas postvittana (Walker) (Tortricidae, Lepidoptera). JOURNAL OF INSECT PHYSIOLOGY 2011; 57:1643-1650. [PMID: 21910995 DOI: 10.1016/j.jinsphys.2011.08.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Revised: 08/23/2011] [Accepted: 08/24/2011] [Indexed: 05/31/2023]
Abstract
The effects of the lipase inhibitor, tetrahydrolipstatin (THL), on neonate Epiphyas postvittana (Walker) (Lepidoptera, Tortricidae) larvae were investigated by feeding on control artificial diets (with and without 2% ethanol) and diets containing 2% ethanol and one of three concentrations of THL (0.011%, 0.037% and 0.11%). Small but significant reductions in growth rate, percent pupation and time to pupation were observed for larvae feeding on 2% ethanol control diet compared with standard control diet, but larger reductions in all parameters occurred with increasing THL concentration. Third instar larvae fed 0.011% THL in the diet had 40% of the midgut lipase activity in the relevant control larvae and showed up-regulation of gene expression of the gastric lipase-like family but not the pancreatic lipase-like family of midgut lipases.
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Affiliation(s)
- Ngaire P Markwick
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 92169, Auckland 1142, New Zealand
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17
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Christeller JT, Amara S, Carrière F. Galactolipase, phospholipase and triacylglycerol lipase activities in the midgut of six species of lepidopteran larvae feeding on different lipid diets. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:1232-1239. [PMID: 21704634 DOI: 10.1016/j.jinsphys.2011.05.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 05/20/2011] [Accepted: 05/24/2011] [Indexed: 05/31/2023]
Abstract
Galactolipase, phospholipase and triacylglycerol lipase activities were measured from the midgut of six species of lepidopteran larvae, two folivores, Epiphyas postvittana (Tortricidae) and Helicoverpa armigera (Noctuidae); two granivores, Plodia interpunctella (Pyralidae) and Ephestia kuehniella (Pyrallidae); a presumptive carnivore, Galleria mellonella (Pyralidae); and a keratinophage, Tineola bisselliella (Tineidae). Galactolipase has not been previously reported in insects. Galactolipase and phospholipase activities were high in the folivores and triacylglycerol lipase activity was low, matching the high galactolipid content of leaves. Conversely, galactolipase and phospholipase activities were low, but not absent, and triacylglycerol lipase activity high in the four other non-folivorous species, matching the high acylglycerol content of their diets. These data suggest the utility of reclassification, for evolutionary studies, of phytophagous lepidoptera into two feeding classes; folivore and granivore, the latter having similarity to the fungivore line of feeders in terms of its lipase activities and ability to retrieve essential polyunsaturated long chain fatty acids from their diets. All the digestive lipases have alkaline pH optima for activity, matching the pH of the lepidopteran midgut and their amino acid content show modifications likely to stabilize the proteins in that environment.
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