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Bleau JR, Gaur N, Fu Y, Bos JIB. Unveiling the Slippery Secrets of Saliva: Effector Proteins of Phloem-Feeding Insects. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:211-219. [PMID: 38148271 DOI: 10.1094/mpmi-10-23-0167-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Phloem-feeding insects include many important agricultural pests that cause crop damage globally, either through feeding-related damage or upon transmission of viruses and microbes that cause plant diseases. With genetic crop resistances being limited to most of these pests, control relies on insecticides, which are costly and damaging to the environment and to which insects can develop resistance. Like other plant parasites, phloem-feeding insects deliver effectors inside their host plants to promote susceptibility, most likely by a combination of suppressing immunity and promoting nutrient availability. The recent emergence of the effector paradigm in plant-insect interactions is highlighted by increasing availability of effector repertoires for a range of species and a broadening of our knowledge concerning effector functions. Here, we focus on recent progress made toward identification of effector repertoires from phloem-feeding insects and developments in effector biology that will advance functional characterization studies. Importantly, identification of effector activities from herbivorous insects promises to provide new avenues toward development of crop protection strategies. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Jade R Bleau
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD2 5DA, U.K
| | - Namami Gaur
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD2 5DA, U.K
| | - Yao Fu
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD2 5DA, U.K
| | - Jorunn I B Bos
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD2 5DA, U.K
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, U.K
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Waksman T, Astin E, Fisher SR, Hunter WN, Bos JIB. Computational Prediction of Structure, Function, and Interaction of Myzus persicae (Green Peach Aphid) Salivary Effector Proteins. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:338-346. [PMID: 38171380 DOI: 10.1094/mpmi-10-23-0154-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Similar to plant pathogens, phloem-feeding insects such as aphids deliver effector proteins inside their hosts that act to promote host susceptibility and enable feeding and infestation. Despite exciting progress toward identifying and characterizing effector proteins from these insects, their functions remain largely unknown. The recent groundbreaking development in protein structure prediction algorithms, combined with the availability of proteomics and transcriptomic datasets for agriculturally important pests, provides new opportunities to explore the structural and functional diversity of effector repertoires. In this study, we sought to gain insight into the infection strategy used by the Myzus persicae (green peach aphid) by predicting and analyzing the structures of a set of 71 effector candidate proteins. We used two protein structure prediction methods, AlphaFold and OmegaFold, that produced mutually consistent results. We observed a wide continuous spectrum of structures among the effector candidates, from disordered proteins to globular enzymes. We made use of the structural information and state-of-the-art computational methods to predict M. persicae effector protein properties, including function and interaction with host plant proteins. Overall, our investigation provides novel insights into prediction of structure, function, and interaction of M. persicae effector proteins and will guide the necessary experimental characterization to address new hypotheses. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Thomas Waksman
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
| | - Edmund Astin
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
| | - S Ronan Fisher
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
| | - William N Hunter
- Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
| | - Jorunn I B Bos
- Division of Plant Sciences, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, U.K
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, U.K
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Pavithran S, Murugan M, Mannu J, Yogendra K, Balasubramani V, Sanivarapu H, Harish S, Natesan S. Identification of salivary proteins of the cowpea aphid Aphis craccivora by transcriptome and LC-MS/MS analyses. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 165:104060. [PMID: 38123026 DOI: 10.1016/j.ibmb.2023.104060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 11/29/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
Aphid salivary proteins mediate the interaction between aphids and their host plants. Moreover, these proteins facilitate digestion, detoxification of secondary metabolites, as well as activation and suppression of plant defenses. The cowpea aphid, Aphis craccivora, is an important sucking pest of leguminous crops worldwide. Although aphid saliva plays an important role in aphid plant interactions, knowledge of the cowpea aphid salivary proteins is limited. In this study, we performed transcriptomic and LC-MS/MS analyses to identify the proteins present in the salivary glands and saliva of A. craccivora. A total of 1,08,275 assembled transcripts were identified in the salivary glands of aphids. Of all these assembled transcripts, 53,714 (49.11%) and 53,577 (49.48%) transcripts showed high similarity to known proteins in the Nr and UniProt databases, respectively. A total of 2159 proteins were predicted as secretory proteins from the salivary gland transcriptome dataset, which contain digestive enzymes, detoxification enzymes, previously known effectors and elicitors, and potential proteins whose functions have yet to be determined. The proteomic analysis of aphid saliva resulted in the identification of 171 proteins. Tissue-specific expression of selected genes using RT-PCR showed that three genes were expressed only in the salivary glands. Overall, our results provide a comprehensive repertoire of cowpea aphid salivary proteins from the salivary gland and saliva, which will be a good resource for future effector functional studies and might also be useful for sustainable aphid management.
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Affiliation(s)
- Shanmugasundram Pavithran
- Department of Agricultural Entomology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Marimuthu Murugan
- Department of Agricultural Entomology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, 641003, India.
| | - Jayakanthan Mannu
- Department of Plant Molecular Biology and Bioinformatics, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Kalenahalli Yogendra
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, 502324, India
| | - Venkatasamy Balasubramani
- Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
| | - Hemalatha Sanivarapu
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Hyderabad, 502324, India
| | - Sankarasubramanian Harish
- Department of Plant Pathology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India
| | - Senthil Natesan
- Department of Plant Molecular Biology and Bioinformatics, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, 641003, India
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Zhang H, Lin R, Liu Q, Lu J, Qiao G, Huang X. Transcriptomic and proteomic analyses provide insights into host adaptation of a bamboo-feeding aphid. FRONTIERS IN PLANT SCIENCE 2023; 13:1098751. [PMID: 36714746 PMCID: PMC9874943 DOI: 10.3389/fpls.2022.1098751] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
INTRODUCTION Salivary glands and their secreted proteins play an important role in the feeding process of sap-sucking aphids. The determination of saliva composition is an important step in understanding host plant adaptation of aphids. Pseudoregma bambucicola is a severe bamboo pest in subtropical areas and the only aphid species that can exclusively feed on hard stalks of bamboos. How this species can penetrate and degrade hard bamboo cell walls and utilize a very specialized niche are important unanswered questions. METHODS In this study, comprehensive analyses based on transcriptome sequencing, RT-qPCR, liquid chromatography-tandem spectrometry (LC-MS/MS) and bioinformatics were conducted on dissected salivary glands and secreted saliva of P. bambucicola to characterize the overall gene expression and salivary protein composition, and to identify putative effector proteins important for aphid-plant interactions. RESULTS AND DISCUSSION Some secretory proteins homologous to known aphid effectors important for aphid-plant interactions, such as digestive enzymes, detoxifying and antioxidant enzymes and some effectors modulating plant defenses, are also detected in salivary gland transcriptome and salivary gland and/or saliva secretomes in P. bambucicola. This indicates that these effectors are probably be essential for enabling P. bambucicola feeding on bamboo host. Although several plant cell wall degrading enzymes (PCWDEs) can be identified from transcriptome, most of the enzymes identified in salivary glands showed low expression levels and they only represent a small fraction of the complete set of enzymes for degrading cellulose and hemicellulose. In addition, our data show that P. bambucicola has no its own ability to produce pectinases. Overall, our analyses indicate that P. bambucicola may lose its own ability to express and secrete key PCWDEs, and its adaptation to unique feeding habit may depend on its symbiotic bacteria.
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Affiliation(s)
- Hui Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Ruixun Lin
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qian Liu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jianjun Lu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Gexia Qiao
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xiaolei Huang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
- Fujian Provincial Key Laboratory of Insect Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
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Yang L, Tian Y, Fang Y, Chen ML, Smagghe G, Niu J, Wang JJ. A saliva α-glucosidase MpAgC2-2 enhance the feeding of green peach aphid Myzus persicae via extra-intestinal digestion. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2022; 150:103846. [PMID: 36202385 DOI: 10.1016/j.ibmb.2022.103846] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
Aphids feed on plant phloem sap that contains massive amounts of sucrose; this not only provides vital nutrition for the aphids but also produces high osmotic pressure. To utilize this carbon source and overcome the osmotic pressure, sucrose is hydrolyzed into the monosaccharides, glucose and fructose. In the green peach aphid (Myzus persicae), we show that this process is facilitated by a key α-glucosidase (MpAgC2-2), which is abundant in the aphid salivary gland and is secreted into leaves during feeding. MpAgC2-2 has a pH optimum of 8.0 in vitro, suggesting it has adapted to the environment of plant cells. Silencing MpAgC2-2 (but not the gut-specific MpAgC3-4) significantly increased the amount of sucrose ingested and hindered aphid feeding on the phloem of tobacco seedlings, resulting in a smaller body size, as well as lower α-glucosidase activity and glucose levels. These effects could be rescued by feeding aphids on tobacco plants transiently expressing MpAgC2-2. The transient expression of MpAgC2-2 also led to the hydrolysis of sucrose in tobacco leaves. Taken together, these results demonstrate that MpAgC2-2 is a salivary protein that facilitates extra-intestinal feeding via sucrose hydrolysis. Our findings provide insight into the ability of aphids to digest the high concentration of sucrose in phloem, and the underlying mechanism of extra-intestinal digestion.
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Affiliation(s)
- Li Yang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China; International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China.
| | - Yuan Tian
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China; International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China.
| | - Ying Fang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China.
| | - Meng-Ling Chen
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China; International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China.
| | - Guy Smagghe
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China; International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China; Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
| | - Jinzhi Niu
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China; International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China.
| | - Jin-Jun Wang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China; International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China.
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Nicolis VF, Burger NFV, Botha AM. Whole-body transcriptome mining for candidate effectors from Diuraphis noxia. BMC Genomics 2022; 23:493. [PMID: 35799109 PMCID: PMC9264610 DOI: 10.1186/s12864-022-08712-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 06/20/2022] [Indexed: 11/30/2022] Open
Abstract
Background Proteins within aphid saliva play a crucial role as the molecular interface between aphids and their host plants. These salivary effectors modulate plant responses to favour aphid feeding and facilitate infestation. The identification of effectors from economically important pest species is central in understanding the molecular events during the aphid-plant interaction. The Russian wheat aphid (Diuraphis noxia, Kurdjumov) is one such pest that causes devastating losses to wheat and barley yields worldwide. Despite the severe threat to food security posed by D. noxia, the non-model nature of this pest and its host has hindered progress towards understanding this interaction. In this study, in the absence of a salivary gland transcriptome, whole-body transcriptomics data was mined to generate a candidate effector catalogue for D. noxia. Results Mining the transcriptome identified 725 transcripts encoding putatively secreted proteins amongst which were transcripts specific to D. noxia. Six of the seven examined D. noxia putative effectors, termed DnE’s (Diuraphis noxia effectors) exhibited salivary gland-specific expression. A comparative analysis between whole-body D. noxia transcriptome data versus the head and body transcriptomes from three other aphid species allowed us to define a catalogue of transcripts putatively upregulated in D. noxia head tissue. Five of these were selected for RT-qPCR confirmation, and were found to corroborate the differential expression predictions, with a further three confirmed to be highly expressed in D. noxia salivary gland tissue. Conclusions Determining a putative effector catalogue for D. noxia from whole-transcriptome data, particularly the identification of salivary-specific sequences potentially unique to D. noxia, provide the basis for future functional characterisation studies to gain further insight into this aphid-plant interaction. Furthermore, due to a lack of publicly available aphid salivary gland transcriptome data, the capacity to use comparative transcriptomics to compile a list of putative effector candidates from whole-body transcriptomics data will further the study of effectors in various aphid species. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08712-4.
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Affiliation(s)
- Vittorio F Nicolis
- Genetics Department, Stellenbosch University, Stellenbosch, 7600, South Africa
| | - N Francois V Burger
- Genetics Department, Stellenbosch University, Stellenbosch, 7600, South Africa
| | - Anna-Maria Botha
- Genetics Department, Stellenbosch University, Stellenbosch, 7600, South Africa.
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Stern DL, Han C. OUP accepted manuscript. Genome Biol Evol 2022; 14:6602283. [PMID: 35660862 PMCID: PMC9168663 DOI: 10.1093/gbe/evac069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/09/2022] [Accepted: 05/03/2022] [Indexed: 11/14/2022] Open
Abstract
Homology of highly divergent genes often cannot be determined from sequence similarity alone. For example, we recently identified in the aphid Hormaphis cornu a family of rapidly evolving bicycle genes, which encode novel proteins implicated as plant gall effectors, and sequence similarity search methods yielded few putative bicycle homologs in other species. Coding sequence-independent features of genes, such as intron-exon boundaries, often evolve more slowly than coding sequences, however, and can provide complementary evidence for homology. We found that a linear logistic regression classifier using only structural features of bicycle genes identified many putative bicycle homologs in other species. Independent evidence from sequence features and intron locations supported homology assignments. To test the potential roles of bicycle genes in other aphids, we sequenced the genome of a second gall-forming aphid, Tetraneura nigriabdominalis and found that many bicycle genes are strongly expressed in the salivary glands of the gall forming foundress. In addition, bicycle genes are strongly overexpressed in the salivary glands of a non-gall forming aphid, Acyrthosiphon pisum, and in the non-gall forming generations of H. cornu. These observations suggest that Bicycle proteins may be used by multiple aphid species to manipulate plants in diverse ways. Incorporation of gene structural features into sequence search algorithms may aid identification of deeply divergent homologs, especially of rapidly evolving genes involved in host-parasite interactions.
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Affiliation(s)
| | - Clair Han
- Janelia Research Campus of the Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
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