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Liu H, Deng B, Chen FH, Suo JQ, Ouyang GC, Lu HL, Chen DS, Meng X. Effector enrichment by Candidatus Liberibacter promotes Diaphorina citri feeding via Jasmonic acid pathway suppression. PEST MANAGEMENT SCIENCE 2024; 80:4013-4023. [PMID: 38554028 DOI: 10.1002/ps.8107] [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: 01/10/2024] [Revised: 03/09/2024] [Accepted: 03/30/2024] [Indexed: 04/01/2024]
Abstract
BACKGROUND Citrus huanglongbing (HLB) is a devastating disease caused by Candidatus Liberibacter asiaticus (CLas) that affects the citrus industry. In nature, CLas relies primarily on Diaphorina citri Kuwayama as its vector for dissemination. After D. citri ingests CLas-infected citrus, the pathogen infiltrates the insect's body, where it thrives, reproduces, and exerts regulatory control over the growth and metabolism of D. citri. Previous studies have shown that CLas alters the composition of proteins in the saliva of D. citri, but the functions of these proteins remain largely unknown. RESULTS In this study, we detected two proteins (DcitSGP1 and DcitSGP3) with high expression levels in CLas-infected D. citri. Quantitative PCR and Western blotting analysis showed that the two proteins were highly expressed in the salivary glands and delivered into the host plant during feeding. Silencing the two genes significantly decreased the survival rate for D. citri, reduced phloem nutrition sucking and promoted jasmonic acid (JA) defenses in citrus. By contrast, after overexpressing the two genes in citrus, the expression levels of JA pathway-associated genes decreased. CONCLUSION Our results suggest that CLas can indirectly suppress the defenses of citrus and support feeding by D. citri via increasing the levels of effectors in the insect's saliva. This discovery facilitates further research into the interaction between insect vectors and pathogens. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Hao Liu
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, China
| | - Bin Deng
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, China
| | - Feng-Hao Chen
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, China
| | - Jia-Qi Suo
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, China
| | - Ge-Cheng Ouyang
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, China
| | - Hui-Lin Lu
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, China
| | - Da-Song Chen
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, China
| | - Xiang Meng
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, China
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Yuan CY, Gao YF, Liu Y, Fan JY, Yuan YZ, Yi L, Jing TX, Dou W, Wang JJ. Candidatus Liberibacter asiaticus influences the emergence of the Asian citrus psyllid Diaphorina citri by regulating key cuticular proteins. INSECT SCIENCE 2024. [PMID: 38881212 DOI: 10.1111/1744-7917.13404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/16/2024] [Accepted: 05/07/2024] [Indexed: 06/18/2024]
Abstract
The Asian citrus psyllid, Diaphorina citri, is the primary vector of the HLB pathogen, Candidatus Liberibacter asiaticus (CLas). The acquisition of CLas shortens the developmental period of nymphs, accelerating the emergence into adulthood and thereby facilitating the spread of CLas. Cuticular proteins (CPs) are involved in insect emergence. In this study, we investigated the molecular mechanisms underlying CLas-promoted emergence in D. citri via CP mediation. Here, a total of 159 CP genes were first identified in the D. citri genome. Chromosomal location analysis revealed an uneven distribution of these CP genes across the 13 D. citri chromosomes. Proteomic analysis identified 54 differentially expressed CPs during D. citri emergence, with 14 CPs exhibiting significant differential expression after CLas acquisition. Five key genes, Dc18aa-1, Dc18aa-2, DcCPR-24, DcCPR-38 and DcCPR-58, were screened from the proteome and CLas acquisition. The silencing of these 5 genes through a modified feeding method significantly reduced the emergence rate and caused various abnormal phenotypes, indicating the crucial role that these genes play in D. citri emergence. This study provides a comprehensive overview of the role of CPs in D. citri and reveals that CLas can influence the emergence process of D. citri by regulating the expression of CPs. These key CPs may serve as potential targets for future research on controlling huanglongbing (HLB) transmission.
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Affiliation(s)
- Chen-Yang Yuan
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Yi-Fan Gao
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Yi Liu
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Jia-Yao Fan
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Ying-Zhe Yuan
- National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing, China
| | - Long Yi
- National Navel Orange Engineering Research Center, Gannan Normal University, Ganzhou, Jiangxi Province, China
| | - Tian-Xing Jing
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - Wei Dou
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), 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
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Academy of Agricultural Sciences, Southwest University, Chongqing, China
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Zhao ST, Ran XT, Huang YY, Sang W, Derrick BE, Qiu BL. Transcriptomic response of citrus psyllid salivary glands to the infection of citrus Huanglongbing pathogen. BULLETIN OF ENTOMOLOGICAL RESEARCH 2024:1-20. [PMID: 38444234 DOI: 10.1017/s0007485324000038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the key vector insect transmitting the Candidatus Liberibacter asiaticus (CLas) bacterium that causes the devastating citrus greening disease (Huanglongbing, HLB) worldwide. The D. citri salivary glands (SG) exhibit an important barrier against the transmission of HLB pathogen. However, knowledge on the molecular mechanism of SG defence against CLas infection is still limited. In the present study, we compared the SG transcriptomic response of CLas-free and CLas-infected D. citri using an illumine paired-end RNA sequencing. In total of 861 differentially expressed genes (DEGs) in the SG upon CLas infection, including 202 upregulated DEGs and 659 downregulated DEGs were identified. Functional annotation analysis showed that most of the DEGs were associated with cellular processes, metabolic processes, and the immune response. Gene ontology and Kyoto Encyclopaedia of Genes and Genomes enrichment analyses revealed that these DEGs were enriched in pathways involving carbohydrate metabolism, amino acid metabolism, the immune system, the digestive system, the lysosome, and endocytosis. A total of 16 DEGs were randomly selected to further validate the accuracy of RNA-Seq dataset by reverse-transcription quantitative polymerase chain reaction. This study provides substantial transcriptomic information regarding the SG of D. citri in response to CLas infection, which may shed light on the molecular interaction between D. citri and CLas, and provides new ideas for the prevention and control of citrus psyllid.
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Affiliation(s)
- San-Tao Zhao
- Engineering Research Centre of Biological Control, Ministry of Education, South China Agricultural University, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Engineering Research Center of Biotechnology for Active Substances, Ministry of Education, Chongqing Normal University, Chongqing 401331, China
| | - Xiao-Tong Ran
- Engineering Research Centre of Biological Control, Ministry of Education, South China Agricultural University, Guangzhou 510642, China
- Engineering Research Center of Biotechnology for Active Substances, Ministry of Education, Chongqing Normal University, Chongqing 401331, China
| | - Yu-Yang Huang
- Engineering Research Centre of Biological Control, Ministry of Education, South China Agricultural University, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Wen Sang
- Engineering Research Centre of Biological Control, Ministry of Education, South China Agricultural University, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | | | - Bao-Li Qiu
- Engineering Research Centre of Biological Control, Ministry of Education, South China Agricultural University, Guangzhou 510642, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
- Engineering Research Center of Biotechnology for Active Substances, Ministry of Education, Chongqing Normal University, Chongqing 401331, China
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Roddee J, Wangkeeree J, Backus EA, Hanboonsong Y. Probing behavior of the leafhopper analyzed through DC electropenetrography and microscopy. JOURNAL OF INSECT PHYSIOLOGY 2023; 151:104584. [PMID: 37977343 DOI: 10.1016/j.jinsphys.2023.104584] [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: 05/12/2023] [Revised: 10/14/2023] [Accepted: 11/12/2023] [Indexed: 11/19/2023]
Abstract
Yamatotettix flavovittatus Matsumara is a new leafhopper species vector of sugarcane white leaf (SCWL) phytoplasma that causes sugarcane chlorosis symptoms. The effects of probing behavior of Y. flavovittatus on sugarcane and its implication for SCWL phytoplasma transmission are yet to be studied. In this research, we used DC electropenetrography (EPG) to define waveforms produced by adult and fifth-instar nymphal Y. flavovittatus on sugarcane and correlated them with salivary sheath termini (likely stylet tip locations) via light and scanning electron microscopy. The following six waveforms and associated activities are described: (NP) non-probing, (Yf1) stylet probing into epidermal cells, (Yf2) stylet probing through mesophyll/parenchyma, (Yf3) stylet contact with phloem and likely watery salivation, (Yf4) active ingestion of sap from phloem, probably sieve elements, and (Yf5) unknown stylet activity in multiple cell types. Study findings reveal that the Y. flavovittatus vector ingests sieve tube element more frequently and for longer durations than any other cell type, supporting that Y. flavovittatus is primarily a phloem feeder. Adult Y. flavovittatus show a longer total probing duration and produces a high density of puncture holes on sugarcane leaves. Moreover, probing behaviors revealed that adults typically ingest phloem sap more frequently and for longer durations than fifth-instar nymphs, enhancing sap ingestion. Furthermore, we propose that adults are more likely to acquire (during Yf4) and inoculate (during Yf3) higher amounts of phytoplasma than fifth-instar nymphs. This information on the penetration behavior of leafhopper Y. flavovittatus serves as a basis for advanced studies on the transmission mechanism of SCWL phytoplasma.
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Affiliation(s)
- Jariya Roddee
- School of Crop Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, Suranaree, Muang, 30000, Nakhon Ratchasima, Thailand.
| | - Jureemart Wangkeeree
- Department of Agricultural Technology, Faculty of Science and Technology, Thammasat University Rangsit Centre, Khlong Nueng, Klong Luang, 10200, Pathum Thani, Thailand
| | - Elaine A Backus
- USDA Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Ave., Parlier, 93648-9757, CA, USA
| | - Yupa Hanboonsong
- Department of Entomology and Plant Pathology, Faculty of Agriculture, Khon Kaen University, Nai Muang, Muang, 40002, Khon Kaen, Thailand
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Ebert TA, Shawer D, Brlansky RH, Rogers ME. Seasonal Patterns in the Frequency of Candidatus Liberibacter Asiaticus in Populations of Diaphorina citri (Hemiptera: Psyllidae) in Florida. INSECTS 2023; 14:756. [PMID: 37754724 PMCID: PMC10532026 DOI: 10.3390/insects14090756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/28/2023]
Abstract
Candidatus Liberibacter asiaticus (CLas) is one of the putative causal agents of huanglongbing, which is a serious disease in citrus production. The pathogen is transmitted by Diaphorina citri Kuwayama (Hemiptera: Psyllidae). As an observational study, six groves in central Florida and one grove at the southern tip of Florida were sampled monthly from January 2008 through February 2012 (50 months). The collected psyllids were sorted by sex and abdominal color. Disease prevalence in adults peaked in November, with a minor peak in February. Gray/brown females had the highest prevalence, and blue/green individuals of either sex had the lowest prevalence. CLas prevalence in blue/green females was highly correlated with the prevalence in other sexes and colors. Thus, the underlying causes for seasonal fluctuations in prevalence operated in a similar fashion for all psyllids. The pattern was caused by larger nymphs displacing smaller ones from the optimal feeding sites and immunological robustness in different sex-color morphotypes. Alternative hypotheses were also considered. Improving our understanding of biological interactions and how to sample them will improve management decisions. We agree with other authors that psyllid management is critical year-round.
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Affiliation(s)
- Timothy A. Ebert
- Citrus Research and Education Center, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA; (R.H.B.); (M.E.R.)
| | - Dalia Shawer
- Department of Economic Entomology, Faculty of Agriculture, Kafr Elsheikh University, Kafr Elsheikh 33516, Egypt;
| | - Ron H. Brlansky
- Citrus Research and Education Center, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA; (R.H.B.); (M.E.R.)
| | - Michael E. Rogers
- Citrus Research and Education Center, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA; (R.H.B.); (M.E.R.)
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Hosseinzadeh S, Heck M. Variations on a theme: factors regulating interaction between Diaphorina citri and "Candidatus Liberibacter asiaticus" vector and pathogen of citrus huanglongbing. CURRENT OPINION IN INSECT SCIENCE 2023; 56:101025. [PMID: 36990150 DOI: 10.1016/j.cois.2023.101025] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/20/2023] [Accepted: 03/20/2023] [Indexed: 05/03/2023]
Abstract
Diaphorina citri, the Asian citrus psyllid, is a vector of Candidatus Liberibacter asiaticus (CLas), the causal agent of huanglongbing (HLB), the world's most serious disease of citrus. Owing to the relevancy and urgency of HLB research, the study of transmission biology in the HLB pathosystem has been a significant area of research. The focus of this article is to summarize and synthesize recent advancements in transmission biology between D. citri and CLas to create an updated view of the research landscape and to identify avenues for future research. Variability appears to play an important role in the transmission of CLas by D. citri. We advocate that it is important to understand the genetic basis for and environmental factors contributing to CLas transmission and how that variation may be exploited to develop and improve HLB control tactics.
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Affiliation(s)
- Saeed Hosseinzadeh
- Plant Pathology and Plant Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Michelle Heck
- Plant Pathology and Plant Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA; Emerging Pests and Pathogens Research Unit, USDA Agricultural Research Service, Ithaca, NY 14853, USA.
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Wang Z, Tan D, Wang F, Guo S, Liu J, Cuthbertson AGS, Qiu B, Sang W. Insulin peptides and their receptors regulate ovarian development and oviposition behavior in Diaphorina citri. INSECT SCIENCE 2023; 30:95-108. [PMID: 35510515 PMCID: PMC10084437 DOI: 10.1111/1744-7917.13048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 03/19/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
Diaphorina citri is an important vector of Citrus Huanglongbing (HLB) disease. After feeding on young host plant shoots, the population of D. citri can increase significantly. Females also only lay eggs on young shoots. However, there are few studies on the mechanism of this phenomenon. Exogenous nutrient signals can affect the insulin signaling system of D. citri after feeding on young shoots. In this study, the expression of upstream factors DcILP1, DcILP2, and DcIR in the insulin signaling system of D. citri was upregulated after feeding on young shoots. After being silenced by RNA interference technology, the results showed that the number of oviposited eggs of D. citri was significantly decreased and the ovarian development was inhibited with severe vacuolation. In addition, detection using quantitative reverse transcription-polymerase chain reaction showed that the upstream regulatory gene DcRheb of the target of rapamycin (TOR) pathway and the downstream reproduction-related DcVg gene were also significantly downregulated. These results suggest that feeding upon young shoots may upregulate the expression levels of upstream factors DcILP1, DcILP2, and DcIR in the insulin signaling system. The signal will be through upregulating the expression of DcRheb, an upstream gene of the TOR signaling pathway. This in turn influences yolk metabolism, which eventually causes the ovaries of female D. citri to mature and therefore initiate oviposition behavior.
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Affiliation(s)
- Ziye Wang
- Key Laboratory of Bio‐Pesticide Innovation and Application of Guangdong ProvinceSouth China Agricultural UniversityGuangzhouChina
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
| | - Delong Tan
- Institute of Facility AgricultureGuangdong Academy of Agricultural SciencesGuangzhouChina
| | - Feifeng Wang
- Key Laboratory of Bio‐Pesticide Innovation and Application of Guangdong ProvinceSouth China Agricultural UniversityGuangzhouChina
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
| | - Shuhao Guo
- Key Laboratory of Bio‐Pesticide Innovation and Application of Guangdong ProvinceSouth China Agricultural UniversityGuangzhouChina
| | - Jinhua Liu
- Natural Medicine Institute of Zhejiang YangShengTang Co.LTDHangzhouChina
| | | | - Baoli Qiu
- Key Laboratory of Bio‐Pesticide Innovation and Application of Guangdong ProvinceSouth China Agricultural UniversityGuangzhouChina
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
| | - Wen Sang
- Key Laboratory of Bio‐Pesticide Innovation and Application of Guangdong ProvinceSouth China Agricultural UniversityGuangzhouChina
- Guangdong Laboratory for Lingnan Modern AgricultureGuangzhouChina
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Wang FF, Wang MH, Zhang MK, Qin P, Cuthbertson AGS, Lei CL, Qiu BL, Yu L, Sang W. Blue light stimulates light stress and phototactic behavior when received in the brain of Diaphorina citri. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 251:114519. [PMID: 36634478 DOI: 10.1016/j.ecoenv.2023.114519] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/31/2022] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
Blue light with a wavelength of 400-470 nm is the composition of the visible light. However, in recent years, blue light contributed the most significance to light pollution due to the artificial light at night. Previously, we have demonstrated that the Asian citrus psyllid (ACP), Diaphorina citri, an important pest in citrus production, has significant positive phototaxis with a light-emitting diode light of 400 nm. In this study, ACP with positive phototactic behavior to 400 nm light (PH) and non-phototactic behavior to 400 nm light (NP) were collected, individually. Transcriptome dynamics of head tissues of PH and NP groups were captured by using RNA-sequencing technology, respectively. Forty-three to 46 million clean reads with high-quality values were obtained, and 1773 differential expressed genes (DEGs) were detected. Compared with the NP group, there were 841 up-regulated DEGs and 932 down-regulated DEGs in the PH group. Eight pathways were significantly enriched in the PH group in the KEGG database, while 43 up-regulated pathways and 25 down-regulated pathways were significantly enriched in the PH group in the GO database. The DGE approach was reliable validated by real time quantitative PCR. Results indicated that the blue light acted as an abiotic stress causing physiological and biochemical responses such as oxidative stress, protein denaturation, inflammation and tumor development in ACPs. Additionally, the light was absorbed by photoreceptors of ACPs, and converted into electrical signal to regulate neuromodulation. This study provides basic information for understanding the molecular mechanisms of ACP in response to blue light and provides a reference for further studies to elucidate phototactic behavior.
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Affiliation(s)
- Fei-Feng Wang
- South China Agricultural University, Guangzhou 510640, China
| | - Ming-Hui Wang
- South China Agricultural University, Guangzhou 510640, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510640, China
| | - Meng-Ke Zhang
- South China Agricultural University, Guangzhou 510640, China
| | - Peng Qin
- South China Agricultural University, Guangzhou 510640, China
| | | | - Chao-Liang Lei
- Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Huazhong Agricultural University, Wuhan 430070, China
| | - Bao-Li Qiu
- South China Agricultural University, Guangzhou 510640, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510640, China
| | - Lin Yu
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Key Laboratory of Green Prevention and Control on Fruits and Vegetables in South China Ministry of Agriculture and Rural Affairs, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou 510640, China.
| | - Wen Sang
- South China Agricultural University, Guangzhou 510640, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510640, China.
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Li J, He P, He P, Li Y, Wu Y, Lu Z, Li X, Yang Y, Wang Y, Guo J, Munir S, He Y. Potential of citrus endophyte Bacillus subtilis L1-21 in the control of Candidatus Liberibacter asiaticus in Asian citrus psyllid, Diaphorina citri. PEST MANAGEMENT SCIENCE 2022; 78:5164-5171. [PMID: 36114796 DOI: 10.1002/ps.7134] [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: 02/01/2022] [Revised: 08/08/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Asian citrus psyllid (ACP), also known as Diaphorina citri, is the natural vector of Candidatus Liberibacter asiaticus (CLas), which is responsible for Huanglongbing (HLB), a devastating citrus disease. Previously, the pathogen was successfully excluded from diseased citrus plants by using the indigenous endophyte Bacillus subtilis L1-21. However, the pathogen elimination and colonization potential of B. subtilis L1-21 in the carrier vector ACP, as well as the recruitment of native microbial communities of psyllid in the presence of endophytes, are still unknown. RESULTS Initially, we suggested that endophyte L1-21 reduced the CLas copies in ACP from 6.58 × 106 to 5.04 × 104 per insect after 48 h, however, the pathogen copies remained stable in the negative control. The endophyte was stable for 48 h after application. Among the bacterial genera those highlighted in ACP were Candidatus Liberibacter, Pseudomonas, Candidatus Profftella, Methylobacterium-Methylorubrum, Pantoea, Curtobacterium, Wolbachia, Actinomycetospora, and Bacillus. Interestingly, B. subtilis L1-21 easily colonizes the midgut of ACP but cannot be detected in eggs. When ACP with endophyte L1-21 was allowed to feed on new citrus leaves, the highest colonization was observed. We also found that psyllids carrying endophyte L1-21 after feeding on citrus leaves reduced the CLas copies in leaves on the 0, 3rd and 5th day from 8.18 × 10,4 2.6 × 10,3 and 0 pathogen copies/g fresh midvein, respectively. CONCLUSIONS We propose that B. subtilis L1-21 is a native endophyte in citrus and psyllid, which efficiently reduces the CLas pathogen in both citrus and psyllids, provides a more protective effect by increasing the number of cultivable endophytes, and successfully colonizes the midgut of ACP. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Jian Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Pengfei He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Pengbo He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yongmei Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yixin Wu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Zhanjun Lu
- College of Life Sciences, Gannan Normal University, Ganzhou, China
| | - Xingyu Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yongchao Yang
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, China
| | - Yuehu Wang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences (CAS), Kunming, China
| | - Jun Guo
- Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Baoshan, China
| | - Shahzad Munir
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
| | - Yueqiu He
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan Agricultural University, Kunming, China
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Štarhová Serbina L, Gajski D, Pafčo B, Zurek L, Malenovský I, Nováková E, Schuler H, Dittmer J. Microbiome of pear psyllids: A tale about closely related species sharing their endosymbionts. Environ Microbiol 2022; 24:5788-5808. [PMID: 36054322 PMCID: PMC10086859 DOI: 10.1111/1462-2920.16180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 08/20/2022] [Indexed: 01/12/2023]
Abstract
Psyllids are phloem-feeding insects that can transmit plant pathogens such as phytoplasmas, intracellular bacteria causing numerous plant diseases worldwide. Their microbiomes are essential for insect physiology and may also influence the capacity of vectors to transmit pathogens. Using 16S rRNA gene metabarcoding, we compared the microbiomes of three sympatric psyllid species associated with pear trees in Central Europe. All three species are able to transmit 'Candidatus Phytoplasma pyri', albeit with different efficiencies. Our results revealed potential relationships between insect biology and microbiome composition that varied during psyllid ontogeny and between generations in Cacopsylla pyri and C. pyricola, as well as between localities in C. pyri. In contrast, no variations related to psyllid life cycle and geography were detected in C. pyrisuga. In addition to the primary endosymbiont Carsonella ruddii, we detected another highly abundant endosymbiont (unclassified Enterobacteriaceae). C. pyri and C. pyricola shared the same taxon of Enterobacteriaceae which is related to endosymbionts harboured by other psyllid species from various families. In contrast, C. pyrisuga carried a different Enterobacteriaceae taxon related to the genus Sodalis. Our study provides new insights into host-symbiont interactions in psyllids and highlights the importance of host biology and geography in shaping microbiome structure.
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Affiliation(s)
- Liliya Štarhová Serbina
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy.,Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Domagoj Gajski
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Barbora Pafčo
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Ludek Zurek
- Central European Institute of Technology, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic.,Department of Microbiology, Nutrition and Dietetics/CINeZ, Czech University of Life Sciences, Prague, Czech Republic
| | - Igor Malenovský
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Eva Nováková
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Hannes Schuler
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy.,Competence Centre for Plant Health, Free University of Bozen-Bolzano, Bolzano, Italy
| | - Jessica Dittmer
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Bolzano, Italy.,Université d'Angers, Institut Agro, INRAE, IRHS, SFR Quasav, Angers, France
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11
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Guo CF, Qiu JH, Hu YW, Xu PP, Deng YQ, Tian L, Wei YY, Sang W, Liu YT, Qiu BL. Silencing of V-ATPase-E gene causes midgut apoptosis of Diaphorina citri and affects its acquisition of Huanglongbing pathogen. INSECT SCIENCE 2022. [PMID: 36346663 DOI: 10.1111/1744-7917.13146] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 10/20/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
The Asian citrus psyllid, Diaphorina citri Kuwayama, is among the most important pests of citrus. It is the main vector of the Huanglongbing (HLB) pathogen Candidatus Liberibacter asiaticus (CLas), which causes severe losses in citrus crops. Control of D. citri is therefore of paramount importance to reduce the spread of HLB. In this regard, using RNA interference (RNAi) to silence target genes is a useful strategy to control psyllids. In this study, using RNAi, we examined the biological functions of the V-ATPase subunit E (V-ATP-E) gene of D. citri, including its effect on acquisition of CLas. The amino acid sequence of V-ATP-E from D. citri had high homology with proteins from other insects. V-ATP-E was expressed at all D. citri life stages analyzed, and the expression level in mature adults was higher than that of teneral adults. Silencing of V-ATP-E resulted in a significant increase in mortality, reduced body weight, and induced cell apoptosis of the D. citri midgut. The reduced expression of V-ATP-E was indicated to inhibit CLas passing through the midgut and into the hemolymph, leading to a majority of CLas being confined to the midgut. In addition, double-stranded RNA of D. citri V-ATP-E was safe to non-target parasitic wasps. These results suggest that V-ATP-E is an effective RNAi target that can be used in D. citri control to block CLas infection.
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Affiliation(s)
- Chang-Fei Guo
- Engineering Research Center of Biocontrol, Ministry of Education and Guangdong Province, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Jun-Hong Qiu
- Chongqing Key Laboratory of Vector Insects, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Yu-Wei Hu
- Key Laboratory of South China Modern Biological Seed Industry, MARA, National S&T Innovation Center for Modern Agricultural Industry, Guangzhou, China
| | - Pei-Ping Xu
- Engineering Research Center of Biocontrol, Ministry of Education and Guangdong Province, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Ying-Qi Deng
- Engineering Research Center of Biocontrol, Ministry of Education and Guangdong Province, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Ling Tian
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yi-Yun Wei
- Chongqing Key Laboratory of Vector Insects, College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Wen Sang
- Engineering Research Center of Biocontrol, Ministry of Education and Guangdong Province, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Yu-Tao Liu
- Key Laboratory of South China Modern Biological Seed Industry, MARA, National S&T Innovation Center for Modern Agricultural Industry, Guangzhou, China
| | - Bao-Li Qiu
- Engineering Research Center of Biocontrol, Ministry of Education and Guangdong Province, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- Chongqing Key Laboratory of Vector Insects, College of Life Sciences, Chongqing Normal University, Chongqing, China
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12
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Mondal M, Carver M, Brown JK. Characteristics of environmental RNAi in potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Psylloidea: Triozidae). Front Physiol 2022; 13:931951. [PMID: 36330211 PMCID: PMC9623324 DOI: 10.3389/fphys.2022.931951] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 09/20/2022] [Indexed: 11/23/2022] Open
Abstract
RNA interference (RNAi) has potential to become a major tool for integrated management of insect pests of agricultural crops based on sequence-specificity and low doses of rapidly biodegradable dsRNA. Deploying ‘environmental RNAi’ for control of insect vectors of plant pathogens is of increasing interest for combatting emerging plant diseases. Hemipteran insect vectors, including psyllids, are vascular feeders, making their development difficult to control specifically by targeting with pesticidal chemistries. Psyllids transmit “Candidatus Liberibacter solanacearum” the causal organism of potato zebra chip and tomato vein greening diseases, transmitted, respectively, by the potato or tomato psyllid (PoP). Until now, the optimal effective concentration(s) of double-stranded RNA (dsRNA) required for significant gene knockdown and RNAi persistence in PoP have not been determined. The objective of this study was to optimize RNAi in young PoP adults and 3rd instars for screening by oral delivery of dsRNAs. The minimal effective dsRNA concentrations required for robust knockdown and persistence were evaluated by delivering seven concentrations spanning 0.1 ng/μL to 500 ng/μL over post ingestion-access periods (IAP) ranging from 48 h to 12 days. The PoP gene candidates evaluated as targets were vacuolar ATPase subunit A, clathrin heavy chain, and non-fermenting protein 7, which were evaluated for knockdown by qPCR amplification. The minimum and/or the second most effective dsRNA concentration resulting in effective levels of gene knockdown was 100 ng/μL for all three targets. Higher concentrations did not yield further knockdown, indicating potential RISC saturation at the higher doses. Gene silencing post-IAP of 100 ng/μL dsRNA persisted for 3–5 days in adults and nymphs, with the PoP 3rd instar, followed by teneral and mature adults, respectively, exhibiting the most robust RNAi-response.
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Affiliation(s)
- Mosharrof Mondal
- School of Plant Sciences, The University of Arizona, Tucson, AZ, United States
- RNAissance Ag LLC, St. Louis, MO, United States
| | - Megan Carver
- School of Plant Sciences, The University of Arizona, Tucson, AZ, United States
| | - Judith K. Brown
- School of Plant Sciences, The University of Arizona, Tucson, AZ, United States
- *Correspondence: Judith K. Brown,
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13
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Sarkar P, Ghanim M. Interaction of Liberibacter Solanacearum with Host Psyllid Vitellogenin and Its Association with Autophagy. Microbiol Spectr 2022; 10:e0157722. [PMID: 35863005 PMCID: PMC9430699 DOI: 10.1128/spectrum.01577-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/14/2022] [Indexed: 12/28/2022] Open
Abstract
Candidatus Liberibacter solanacearum (CLso) haplotype D, transmitted by the carrot psyllid Bactericera trigonica, is a major constraint for carrot production in Israel. Unveiling the molecular interactions between the psyllid vector and CLso can facilitate the development of nonchemical approaches for controlling the disease caused by CLso. Bacterial surface proteins are often known to be involved in adhesion and virulence; however, interactions of CLso with carrot psyllid proteins that have a role in the transmission process has remained unexplored. In this study, we used CLso outer membrane protein (OmpA) and flagellin as baits to screen for psyllid interacting proteins in a yeast two-hybrid system assay. We identified psyllid vitellogenin (Vg) to interact with both OmpA and flagellin of CLso. As Vg and autophagy are often tightly linked, we also studied the expression of autophagy-related genes to further elucidate this interaction. We used the juvenile hormone (JH-III) to induce the expression of Vg, thapsigargin for suppressing autophagy, and rapamycin for inducing autophagy. The results revealed that Vg negatively regulates autophagy. Induced Vg expression significantly suppressed autophagy-related gene expression and the levels of CLso significantly increased, resulting in a significant mortality of the insect. Although the specific role of Vg remains obscure, the findings presented here identify Vg as an important component in the insect immune responses against CLso and may help in understanding the initial molecular response in the vector against Liberibacter. IMPORTANCE Pathogen transmission by vectors involves multiple levels of interactions, and for the transmission of liberibacter species by psyllid vectors, much of these interactions are yet to be explored. Candidatus Liberibacter solanacearum (CLso) haplotype D inflicts severe economic losses to the carrot industry. Understanding the specific interactions at different stages of infection is hence fundamental and could lead to the development of better management strategies to disrupt the transmission of the bacteria to new host plants. Here, we show that two liberibacter membrane proteins interact with psyllid vitellogenin and also induce autophagy. Altering vitellogenin expression directly influences autophagy and CLso abundance in the psyllid vector. Although the exact mechanism underlying this interaction remains unclear, this study highlights the importance of immune responses in the transmission of this disease agent.
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Affiliation(s)
- Poulami Sarkar
- Department of Entomology, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
| | - Murad Ghanim
- Department of Entomology, Agricultural Research Organization, Volcani Institute, Rishon LeZion, Israel
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14
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Merfa MV, Fischer ER, de Souza E Silva M, Francisco CS, Della Coletta-Filho H, de Souza AA. Probing the Application of OmpA-Derived Peptides to Disrupt the Acquisition of ' Candidatus Liberibacter asiaticus' by Diaphorina citri. PHYTOPATHOLOGY 2022; 112:163-172. [PMID: 34818904 DOI: 10.1094/phyto-06-21-0252-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: 06/13/2023]
Abstract
Huanglongbing (HLB) is currently the most devastating disease of citrus worldwide. Both bacteria 'Candidatus Liberibacter asiaticus' (CLas) and 'Candidatus Liberibacter americanus' (CLam) are associated with HLB in Brazil but with a strong prevalence of CLas over CLam. Conventionally, HLB management focuses on controlling the insect vector population (Diaphorina citri; also known as Asian citrus psyllid [ACP]) by spraying insecticides, an approach demonstrated to be mostly ineffective. Thus, development of novel, more efficient HLB control strategies is required. The multifunctional bacterial outer membrane protein OmpA is involved in several molecular processes between bacteria and their hosts and has been suggested as a target for bacterial control. Curiously, OmpA is absent in CLam in comparison with CLas, suggesting a possible role in host interaction. Therefore, in the current study, we have treated ACPs with different OmpA-derived peptides, aiming to evaluate acquisition of CLas by the insect vector. Treatment of psyllids with 5 µM of Pep1, Pep3, Pep5, and Pep6 in artificial diet significantly reduced the acquisition of CLas, whereas increasing the concentration of Pep5 and Pep6 to 50 µM abolished this process. In addition, in planta treatment with 50 µM of Pep6 also significantly decreased the acquisition of CLas, and sweet orange plants stably absorbed and maintained this peptide for as long as 3 months post the final application. Together, our results demonstrate the promising use of OmpA-derived peptides as a novel biotechnological tool to control CLas.
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Affiliation(s)
- Marcus Vinícius Merfa
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico-IAC, Cordeirópolis, SP 13490-970, Brazil
| | - Eduarda Regina Fischer
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico-IAC, Cordeirópolis, SP 13490-970, Brazil
| | - Mariana de Souza E Silva
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico-IAC, Cordeirópolis, SP 13490-970, Brazil
| | | | | | - Alessandra Alves de Souza
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico-IAC, Cordeirópolis, SP 13490-970, Brazil
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15
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Killiny N. Made for Each Other: Vector-Pathogen Interfaces in the Huanglongbing Pathosystem. PHYTOPATHOLOGY 2022; 112:26-43. [PMID: 34096774 DOI: 10.1094/phyto-05-21-0182-fi] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Citrus greening, or huanglongbing (HLB), currently is the most destructive disease of citrus. HLB disease is putatively caused by the phloem-restricted α-proteobacterium 'Candidatus Liberibacter asiaticus'. This bacterium is transmitted primarily by the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae). Most animal pathogens are considered pathogenic to their insect vectors, whereas the relationships between plant pathogens and their insect vectors are variable. Lately, the relationship of 'Ca. L. asiaticus' with its insect vector, D. citri, has been well investigated at the molecular, biochemical, and biological levels in many studies. Herein, the findings concerning this relationship are discussed and molecular features of the acquisition of 'Ca. L. asiaticus' from the plant host and its growth and circulation within D. citri, as well as its transmission to plants, are presented. In addition, the effects of 'Ca. L. asiaticus' on the energy metabolism (respiration, tricarboxylic acid cycle, and adenosine triphosphate production), metabolic pathways, immune system, endosymbionts, and detoxification enzymes of D. citri are discussed together with other impacts such as shorter lifespan, altered feeding behavior, and higher fecundity. Overall, although 'Ca. L. asiaticus' has significant negative effects on its insect vector, it increases its vector fitness, indicating that it develops a mutualistic relationship with its vector. This review will help in understanding the specific interactions between 'Ca. L. asiaticus' and its psyllid vector in order to design innovative management strategies.
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Affiliation(s)
- Nabil Killiny
- Citrus Research and Education Center, IFAS, University of Florida, Lake Alfred, FL 33850
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16
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Alves KS, Rothmann LA, Del Ponte EM. Linking Climate Variables to Large-Scale Spatial Pattern and Risk of Citrus Huanglongbing: A Hierarchical Bayesian Modeling Approach. PHYTOPATHOLOGY 2022; 112:189-196. [PMID: 34340530 DOI: 10.1094/phyto-05-21-0219-fi] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Huanglongbing (HLB) is one of the most important diseases affecting citriculture in the world. Knowledge of climatic factors linked to HLB risk at large spatial scales is limited. We gathered HLB presence and absence data from official surveys conducted in the state of Minas Gerais, Brazil, over 13 years. The total count of orange and mandarin orchards, and mean orchard area, normalized to a spatial grid of 60 cells (55 × 55 km), were derived from the same database. Monthly climate normals (1984 to 2013) of rainfall, mean temperature, and wind speed split into rainy (September to April) and dry (May to August) seasons (annual summary was retained) were obtained for each grid cell. Two hierarchical Bayesian modeling approaches were evaluated, both based on the integrated nested Laplace approximation method. The first, the climate covariates model (CC model), used orchard, climate, and the spatial effect as covariates. The second, principal components (PC model), used the first three components from a principal component analysis of all variables and the spatial effect as covariates. Both models showed an inverse relationship between posterior prevalence and grid cell mean temperature during the dry season. Annual wind speed, as well as annual and rainy season rainfall, contributed to HLB risk in the CC and PC models, respectively. A partial influence of neighboring regions on HLB risk was observed. The results should assist policymakers in defining regions at HLB risk and guide monitoring strategies to mitigate further spread of HLB in the state of Minas Gerais.
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Affiliation(s)
- Kaique S Alves
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil
| | - Lisa A Rothmann
- Department of Plant Sciences, University of the Free State, Free State, Bloemfontein, 9300, South Africa
| | - Emerson M Del Ponte
- Departamento de Fitopatologia, Universidade Federal de Viçosa, Viçosa, MG 36570-900, Brazil
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17
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Igwe DO, Higgins SA, Heck M. An Excised Leaf Assay to Measure Acquisition of ' Candidatus Liberibacter asiaticus' by Psyllids Associated with Citrus Huanglongbing Disease. PHYTOPATHOLOGY 2022; 112:69-75. [PMID: 33988458 DOI: 10.1094/phyto-03-21-0124-sc] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Huanglongbing, or citrus greening disease, is the most serious disease of citrus worldwide and is associated with plant infection by 'Candidatus Liberibacter asiaticus' (CLas) and other Liberibacter species. CLas is transmitted by Diaphorina citri, the Asian citrus psyllid, in a circulative propagative manner. Circulative propagative transmission is a complex process comprising at least three steps: movement of the pathogen into vector tissues, translocation and replication of the pathogen within the vector host, and pathogen inoculation of a new host by the vector. In this work, we describe an excised leaf CLas acquisition assay, which enables precise measurements of CLas acquisition by D. citri in a streamlined laboratory assay. Briefly, healthy fourth and fifth instar D. citri nymphs acquire CLas from excised CLas-positive leaves, where the insects also complete their developmental cycle. CLas titer in the resulting adults is measured using quantitative PCR and CLas-specific 16S rRNA gene primers. We observed positive correlations between CLas titer in each leaf replicate and the CLas titer that developed in the insects after acquisition (rs = 0.78; P = 0.0002). This simple assay could be used to detect CLas acquisition phenotypes and their underlying genotypes, facilitate assessment of plant factors that impact acquisition, and screen for compounds that interfere with CLas acquisition by delivering these compounds through the excised leaf.
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Affiliation(s)
- David O Igwe
- Plant Pathology and Plant Microbe Biology, School of Integrated Plant Sciences, Cornell University, Ithaca, NY 14853
| | - Steven A Higgins
- Plant Pathology and Plant Microbe Biology, School of Integrated Plant Sciences, Cornell University, Ithaca, NY 14853
- Emerging Pests and Pathogens Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Ithaca, NY 14853
| | - Michelle Heck
- Plant Pathology and Plant Microbe Biology, School of Integrated Plant Sciences, Cornell University, Ithaca, NY 14853
- Emerging Pests and Pathogens Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Ithaca, NY 14853
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18
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Xue A, Liu Y, Li H, Cui M, Huang X, Wang W, Wu D, Guo X, Hao Y, Luo L. Early detection of Huanglongbing with EESI-MS indicates a role of phenylpropanoid pathway in citrus. Anal Biochem 2021; 639:114511. [PMID: 34883070 DOI: 10.1016/j.ab.2021.114511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/15/2021] [Accepted: 12/01/2021] [Indexed: 12/22/2022]
Abstract
Huanglongbing (HLB), a devastating disease for citrus worldwide, is caused by Candidatus Liberibacter asiaticus (CLas). In this study, we employed a novel extractive electrospray ionization-mass spectrometry (EESI-MS) method to analyze the metabolites in leaves of uninfected and HLB-infected Newhall navel orange. The results showed that uninfected and HLB-infected leaves could be readily distinguished based on EESI-MS combined by multivariable analysis. Nine phenolic compounds involved in phenylpropanoid pathway, such as p-coumaric acid, naringin, and apigenin, were principal components to distinguish the leaves of uninfected and HLB-infected Newhall navel orange. Gene expression was also conducted to further explore the molecular mechanism of phenylpropanoid branch pathway in HLB. The expression of genes (4CL, HCT, CHI, CHS, CYP, and C12R) involved in phenylpropanoid branch pathway was increased in asymptomatic and early period of HLB-infected leaves, while decreased in later period of HLB-infected leaves. This study provides a novel method for early detection of citrus HLB and suggests the regulation mechanism of phenylpropanoid pathway in the interaction between citrus and CLas.
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Affiliation(s)
- Ahui Xue
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Yongquan Liu
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Haoxing Li
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Meng Cui
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Xueyong Huang
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Wenjing Wang
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Dong Wu
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Xiali Guo
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Yingbin Hao
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Liping Luo
- School of Life Sciences, Nanchang University, Nanchang, 330031, China; State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, 330047, China.
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19
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Silencing of Aquaporin Homologue Accumulates Uric Acid and Decreases the Lifespan of the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae). INSECTS 2021; 12:insects12100931. [PMID: 34680700 PMCID: PMC8539622 DOI: 10.3390/insects12100931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 09/29/2021] [Accepted: 10/05/2021] [Indexed: 11/18/2022]
Abstract
Simple Summary The use of RNA interference has become increasingly popular for investigating insect physiology, testing the functionality of insect genes and as a potential control strategy. Hemiptera include many vectors for destructive plant diseases. A major characteristic of the order of Hemiptera is feeding on the phloem sap of their plant hosts. Phloem feeders face high osmotic stress between the gut lumen and hemolymph due to the high level of sucrose in phloem sap. Targeting the osmoregulation mechanisms in Diaphorina citri Kuwayama, which transmits ‘Candidatus Liberibacter asiaticus’, the putative causal agent of Huanglongbing in citrus may lead to an effective control strategy. Herein we downregulate the expression of aquaporin, representing a major mechanism of osmoregulation, by RNA interference. Abstract The Asian citrus psyllid, Diaphorina citri Kuwayama is devastating the citrus industry worldwide. It transmits ‘Candidatus Liberibacter asiaticus’, the pathogen of Huanglongbing in citrus. RNA interference is an excellent tool for functional genomics and for screening target genes for pest control. Herein, we silenced the aquaporin (AQP) gene (DcAQP) homologue in D. citri to study its functionality and whether it could be a good target for a control strategy. AQP is an integral membrane channel protein that aids in the rapid flux of water and other small solutes that move across the lipid membrane. In Hemiptera, it is well established that AQP plays important roles in adjusting to physiological challenges including (1) regulating osmotic stress between the gut lumen and hemolymph after imbibing large quantities of a low nitrogen, sugar-rich liquid diet; (2) avoiding or preventing dehydration and desiccation; and (3) surviving at elevated temperatures. The dsRNA-DcAQP was applied twice to nymphs of the 4th and 5th instars through a soaking technique. Silencing AQP caused a significant increase in nymph mortality. Emerged adults showed malformations and a shorter lifespan. Silencing DcAQP provoked alterations in some metabolites and increased the uric acid content in emerged adults. DcAQP could be a useful target to control D. citri.
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20
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Guo SH, Liu YM, Wang ZY, Wang FF, Mao YK, Hu YW, Han P, Cuthbertson AGS, Qiu BL, Sang W. Transcriptome analysis reveals TOR signalling-mediated plant flush shoots governing Diaphorina citri Kuwayama oviposition. INSECT MOLECULAR BIOLOGY 2021; 30:264-276. [PMID: 33410566 DOI: 10.1111/imb.12693] [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: 07/06/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 06/12/2023]
Abstract
Asian Citrus Psyllid (ACP), Diaphorina citri, is a key vector transmitting the causative agent of Huanglongbing (HLB) disease. Population growth of ACP is evident after feeding on plant flush shoots, as they only oviposit here. However, the underlying mechanism as to why flush shoots govern oviposition is unclear. This study compares the fecundity and ovarian morphology of ACP between young flush and mature leaves. Furthermore, the transcriptome of mated females infesting Murraya paniculata was analysed. Finally, the gene of the key Target of Rapamycin (TOR) signalling pathway was silenced by RNAi. Results indicated that flush shoot feeding activated the development of the psyllids ovary and therefore induced oviposition. A total of 126 and 2794 differentially expressed genes were detected at 1 and 5 days, respectively, after pest infestation of flush shoots compared to mature leaves. Many genes are involved in protein metabolism, Mitogen-Activated Protein Kinase (MAPK) signalling pathway, hormone synthesis, and TOR signalling pathway: all thought to activate reproduction. Silencing of the positive regulator gene DcRheb in the TOR pathway resulted in lower levels of ecdysone and juvenile hormone and decreased vitellogenin synthesis, further disrupting reproductive ability. This study enhances understanding of the molecular mechanism underlying ACP's reproductive strategy.
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Affiliation(s)
- S-H Guo
- Key Laboratory of Bio-Pesticide Creation and Application, South China Agricultural University, Guangzhou, China
| | - Y-M Liu
- Key Laboratory of Bio-Pesticide Creation and Application, South China Agricultural University, Guangzhou, China
| | - Z-Y Wang
- Key Laboratory of Bio-Pesticide Creation and Application, South China Agricultural University, Guangzhou, China
| | - F-F Wang
- Key Laboratory of Bio-Pesticide Creation and Application, South China Agricultural University, Guangzhou, China
| | - Y-K Mao
- Guangdong Provincial Bioengineering Institute (Guangzhou Sugarcane Industry Research Institute), Guangzhou, China
| | - Y-W Hu
- Guangdong Provincial Bioengineering Institute (Guangzhou Sugarcane Industry Research Institute), Guangzhou, China
| | - P Han
- CAS Key Laboratory of Biogeography and Bioresource in Arid Land, Chinese Academy of Sciences, Ürümqi, China
| | | | - B-L Qiu
- Key Laboratory of Bio-Pesticide Creation and Application, South China Agricultural University, Guangzhou, China
| | - W Sang
- Key Laboratory of Bio-Pesticide Creation and Application, South China Agricultural University, Guangzhou, China
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21
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Görg LM, Gross J. Influence of ontogenetic and migration stage on feeding behavior of Cacopsylla picta on 'Candidatus Phytoplasma mali' infected and non-infected apple plants. JOURNAL OF INSECT PHYSIOLOGY 2021; 131:104229. [PMID: 33766541 DOI: 10.1016/j.jinsphys.2021.104229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
The summer apple psyllid Cacopsylla picta (Foerster) is the vector of 'Candidatus Phytoplasma mali', the causal agent of apple proliferation disease (AP). During its phloem-feeding activities it transmits this biotrophic bacterium from infected to healthy apple trees (Malus domestica Borkh.) causing high economic losses. During its life cycle, C.picta performs two host switches: In summer, the new adult generation (emigrants) hatch on apples before they emigrate to their overwintering host conifers. The following spring, the overwintered adult generation (remigrants) remigrate into apple orchards for mating and oviposition. The preimaginal stages (nymphs) develop on apple. It is known that phytopathogen-induced changes in plant physiology can affect insect-plant-interactions. In 12 h recordings of electrical penetration graphs (EPG) it was assessed whether 'Ca. P. mali' infection of the plant affected probing and feeding behavior of the vector C.picta. Its life stage and the infection status of the host plant (and the interaction between these factors) significantly affected the first occurrence, duration and frequency of probing and feeding phases. On 'Ca. P. mali' infected plants, the phloem salivation phase occurred later than on non-infected plants. Even though all life stages fed both on phloem and xylem, significant differences were found in the frequency and duration of phloem and xylem ingestion phases. Nymphs spent the shortest time non-probing, earlier started the first leaf penetration and longer ingested xylem compared with adults. Further, phloem phases differed between migratory stages; remigrants had higher numbers of phloem ingestion events and spent longer ingesting phloem than emigrants. For emigrants, however, phloem contact was very rarely observed during our recordings. The impact of our findings for understanding the multitrophic interactions between host plant, pathogen and behavior of vector insects are discussed with regard to the epidemiology of AP and pest control strategies of the vector.
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Affiliation(s)
- Louisa Maria Görg
- Laboratory of Applied Chemical Ecology, Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Schwabenheimer Str. 101, Dossenheim D-69221, Germany
| | - Jürgen Gross
- Laboratory of Applied Chemical Ecology, Institute for Plant Protection in Fruit Crops and Viticulture, Julius Kühn-Institut, Federal Research Institute for Cultivated Plants, Schwabenheimer Str. 101, Dossenheim D-69221, Germany.
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22
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Asian citrus psyllid adults inoculate huanglongbing bacterium more efficiently than nymphs when this bacterium is acquired by early instar nymphs. Sci Rep 2020; 10:18244. [PMID: 33106553 PMCID: PMC7589476 DOI: 10.1038/s41598-020-75249-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/11/2020] [Indexed: 01/25/2023] Open
Abstract
The Asian citrus psyllid (Diaphorina citri) transmits the bacterium 'Candidatus Liberibacter asiaticus' (CLas), which causes huanglongbing (citrus greening) disease, in a circulative-propagative manner. We compared CLas inoculation efficiency of D. citri nymphs and adults into healthy (uninfected) citron leaves when both vector stages were reared from eggs on infected plants. The proportion of CLas-positive leaves was 2.5% for nymphs and 36.3% for adults. CLas acquisition by early instar nymphs followed by dissections of adults and 4th instar nymphs revealed that CLas bacterium had moved into the head-thorax section (containing the salivary glands) in 26.7-30.0% of nymphs and 37-45% of adults. Mean Ct values in these sections were 31.6-32.9 and 26.8-27.0 for nymphs and adults, respectively. Therefore, CLas incidence and titer were higher in the head-thorax of adults than in nymphs. Our results suggest that following acquisition of CLas by early instar D. citri nymphs, emerging adults inoculate the bacteria into citrus more efficiently than nymphs because adults are afforded a longer latent period necessary for multiplication and/or translocation of CLas into the salivary glands of the vector. We propose that CLas uses D. citri nymphs mainly for pathogen acquisition and multiplication, and their adults mainly for pathogen inoculation and spread.
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23
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Huang W, Reyes-Caldas P, Mann M, Seifbarghi S, Kahn A, Almeida RPP, Béven L, Heck M, Hogenhout SA, Coaker G. Bacterial Vector-Borne Plant Diseases: Unanswered Questions and Future Directions. MOLECULAR PLANT 2020; 13:1379-1393. [PMID: 32835885 PMCID: PMC7769051 DOI: 10.1016/j.molp.2020.08.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 06/01/2023]
Abstract
Vector-borne plant diseases have significant ecological and economic impacts, affecting farm profitability and forest composition throughout the world. Bacterial vector-borne pathogens have evolved sophisticated strategies to interact with their hemipteran insect vectors and plant hosts. These pathogens reside in plant vascular tissue, and their study represents an excellent opportunity to uncover novel biological mechanisms regulating intracellular pathogenesis and to contribute to the control of some of the world's most invasive emerging diseases. In this perspective, we highlight recent advances and major unanswered questions in the realm of bacterial vector-borne disease, focusing on liberibacters, phytoplasmas, spiroplasmas, and Xylella fastidiosa.
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Affiliation(s)
- Weijie Huang
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Paola Reyes-Caldas
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA
| | - Marina Mann
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
| | - Shirin Seifbarghi
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA
| | - Alexandra Kahn
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Rodrigo P P Almeida
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, USA
| | - Laure Béven
- UMR 1332 Biologie du Fruit et Pathologie, Univ. Bordeaux, INRAE, Villenave d'Ornon 33882 France
| | - Michelle Heck
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA; Boyce Thompson Institute, Ithaca, NY 14853, USA; Emerging Pests and Pathogens Research Unit, Robert W. Holley Center, USDA ARS, Ithaca, NY 14853, USA
| | - Saskia A Hogenhout
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK; School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA.
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Quintana-González de Chaves M, Teresani GR, Hernández-Suárez E, Bertolini E, Moreno A, Fereres A, Cambra M, Siverio F. ' Candidatus Liberibacter Solanacearum' Is Unlikely to Be Transmitted Spontaneously from Infected Carrot Plants to Citrus Plants by Trioza Erytreae. INSECTS 2020; 11:insects11080514. [PMID: 32784442 PMCID: PMC7469162 DOI: 10.3390/insects11080514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/01/2020] [Accepted: 08/06/2020] [Indexed: 11/16/2022]
Abstract
Bacteria belonging to 'Candidatus Liberibacter spp.' are associated with various severe diseases in the five continents. The African citrus psyllid Trioza erytreae (Hemiptera: Triozidae) is an efficient vector of citrus huanglongbing-HLB disease, absent in the Mediterranean basin. This psyllid is currently present in the islands and mainland Portugal and Spain, where the prevalence of 'Ca. Liberibacter solanacearum' (CaLsol) associated to a carrot disease is high. Trioza erytreae normally feeds on citrus plants but has also been observed on other crops. It would be a great concern to the Mediterranean citrus industry if T. erytreae could transmit this bacterium from carrots to citrus and cause disease; therefore, the transmission of CaLsol from carrot plants to citrus plants was experimentally assessed. Although CaLsol was initially detected on receptor citrus plants in transmission assays by dodder and budding, the infection was not established. The feeding behavior by electrical penetration graphs and oviposition of T. erytreae on carrot plants versus citrus plants was evaluated. Trioza erytreae only reached the phloem in citrus plants. However, it was able to acquire CaLsol from infected carrots but unable to transmit it to citrus plants. CaLsol was detected in some carrot plants immediately after 7 and 14 days (inoculation access period), but it was not detected after one month. Trioza erytreae was unable to complete its life cycle on carrot plants. In conclusion, the efficient vector of bacteria associated to huanglongbing was unable to transmit CaLsol from carrot to citrus plants, but it acquired and transmitted the bacterium from carrot to carrot plants with low efficiency.
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Affiliation(s)
- María Quintana-González de Chaves
- Departamento de Protección Vegetal, Instituto Canario de Investigaciones Agrarias (ICIA), Crta. El Boquerón s/n, 38270 La Laguna, Spain; (E.H.-S.); (F.S.)
- Correspondence:
| | - Gabriela R. Teresani
- APTA-Instituto Agronômico (IAC)-Centro de Pesquisa e Desenvolvimento de Fitossanidade, Campinas 13020-902, Brazil;
| | - Estrella Hernández-Suárez
- Departamento de Protección Vegetal, Instituto Canario de Investigaciones Agrarias (ICIA), Crta. El Boquerón s/n, 38270 La Laguna, Spain; (E.H.-S.); (F.S.)
| | - Edson Bertolini
- Faculdade de Agronomia, Departamento de Fitosanidade, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 7712, Porto Alegre 91540-000, Brazil;
| | - Aránzazu Moreno
- Instituto de Ciencias Agrarias, Consejo Superior de Investigaciones Científicas (CSIC), Calle Serrano, 115, 28006 Madrid, Spain; (A.M.); (A.F.)
| | - Alberto Fereres
- Instituto de Ciencias Agrarias, Consejo Superior de Investigaciones Científicas (CSIC), Calle Serrano, 115, 28006 Madrid, Spain; (A.M.); (A.F.)
| | - Mariano Cambra
- Instituto Valenciano de Investigaciones Agrarias (IVIA), Centro de Protección Vegetal y Biotecnología, Carretera CV-315, Km 10.7, 46113 Moncada, Spain;
| | - Felipe Siverio
- Departamento de Protección Vegetal, Instituto Canario de Investigaciones Agrarias (ICIA), Crta. El Boquerón s/n, 38270 La Laguna, Spain; (E.H.-S.); (F.S.)
- Sección de Laboratorio de Sanidad Vegetal, Consejería de Agricultura, Ganadería y Pesca, Gobierno de Canarias, Ctra. El Boquerón s/n, 28270 La Laguna, Spain
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25
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Gallinger J, Gross J. Phloem Metabolites of Prunus Sp. Rather than Infection with Candidatus Phytoplasma Prunorum Influence Feeding Behavior of Cacopsylla pruni Nymphs. J Chem Ecol 2020; 46:756-770. [PMID: 31965396 PMCID: PMC7429536 DOI: 10.1007/s10886-020-01148-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/11/2019] [Accepted: 01/08/2020] [Indexed: 10/29/2022]
Abstract
Phytoplasmas are specialized small bacteria restricted to the phloem tissue and spread by hemipterans feeding on plant sieve tube elements. As for many other plant pathogens, it is known that phytoplasmas alter the chemistry of their hosts. Most research on phytoplasma-plant interactions focused on the induction of plant volatiles and phytohormones. Little is known about the influence of phytoplasma infections on the nutritional composition of phloem and consequences on vector behavior and development. The plum psyllid Cacopsylla pruni transmits 'Candidatus Phytoplasma prunorum', the causing agent of European Stone Fruit Yellows (ESFY). While several Prunus species are susceptible for psyllid feeding, they show different responses to the pathogen. We studied the possible modulation of plant-insect interactions by bacteria-induced changes in phloem sap chemistry. Therefore, we sampled phloem sap from phytoplasma-infected and non-infected Prunus persica and Prunus insititia plants, which differ in their susceptibility to ESFY and psyllid feeding. Furthermore, the feeding behavior and development of C. pruni nymphs was compared on infected and non-infected P. persica and P. insititia plants. Phytoplasma infection did not affect phloem consumption by C. pruni nymphs nor their development time. In contrast, the study revealed significant differences between P. insititia and P. persica in terms of both phloem chemistry and feeding behavior of C. pruni nymphs. Phloem feeding phases were four times longer on P. insititia than on P. persica, resulting in a decreased development time and higher mortality of vector insects on P. persica plants. These findings explain the low infestation rates of peach cultivars with plum psyllids commonly found in field surveys.
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Affiliation(s)
- Jannicke Gallinger
- Laboratory of Applied Chemical Ecology, Institute for Plant Protection in Fruit Crops and Viticulture, Federal Research Centre for Cultivated Plants, Julius Kühn-Institut, Dossenheim, Germany
- Plant Chemical Ecology, Technical University of Darmstadt, Schnittspahnstr. 4, 64287, Darmstadt, Germany
| | - Jürgen Gross
- Laboratory of Applied Chemical Ecology, Institute for Plant Protection in Fruit Crops and Viticulture, Federal Research Centre for Cultivated Plants, Julius Kühn-Institut, Dossenheim, Germany.
- Plant Chemical Ecology, Technical University of Darmstadt, Schnittspahnstr. 4, 64287, Darmstadt, Germany.
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26
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de Souza Pacheco I, Manzano Galdeano D, Spotti Lopes JR, Machado MA. Development on Infected Citrus over Generations Increases Vector Infection by ' Candidatus Liberibacter Asiaticus in Diaphorina citri'. INSECTS 2020; 11:insects11080469. [PMID: 32722346 PMCID: PMC7469140 DOI: 10.3390/insects11080469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 05/13/2023]
Abstract
'Candidatus Liberibacter asiaticus' (CLas) is a major causal agent of citrus Huanglongbing (HLB), which is transmitted by Asian citrus psyllid (ACP), Diaphorina citri, causing severe losses in various regions of the world. Vector efficiency is higher when acquisition occurs by ACP immature stages and over longer feeding periods. In this context, our goal was to evaluate the progression of CLas population and infection rate over four ACP generations that continuously developed on infected citrus plants. We showed that the frequency of CLas-positive adult samples increased from 42% in the parental generation to 100% in the fourth generation developing on CLas-infected citrus. The bacterial population in the vector also increased over generations. This information reinforces the importance of HLB management strategies, such as vector control and eradication of diseased citrus trees, to avoid the development of CLas-infected ACP generations with higher bacterial loads and, likely, a higher probability of spreading the pathogen in citrus orchards.
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Affiliation(s)
- Inaiara de Souza Pacheco
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 13490-970, Brazil; (D.M.G.); (M.A.M.)
- Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo 13083-862, Brazil
- Correspondence:
| | - Diogo Manzano Galdeano
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 13490-970, Brazil; (D.M.G.); (M.A.M.)
| | - João Roberto Spotti Lopes
- Departamento de Entomologia e Acarologia, Escola Superior de Agricultura “Luiz de Queiroz”—Universidade de São Paulo, Piracicaba, São Paulo 13418-900, Brazil;
| | - Marcos Antonio Machado
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico de Campinas, Cordeirópolis, São Paulo 13490-970, Brazil; (D.M.G.); (M.A.M.)
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Carmo-Sousa M, Garcia RB, Wulff NA, Fereres A, Miranda MP. Drench Application of Systemic Insecticides Disrupts Probing Behavior of Diaphorina citri (Hemiptera: Liviidae) and Inoculation of Candidatus Liberibacter asiaticus. INSECTS 2020; 11:insects11050314. [PMID: 32429404 PMCID: PMC7290861 DOI: 10.3390/insects11050314] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 11/30/2022]
Abstract
Candidatus Liberibacter asiaticus (CLas) is a phloem-limited bacterium that is associated with the Huanglongbing (HLB) disease of citrus and transmitted by the psyllid, Diaphorina citri. There are no curative methods to control HLB and the prevention of new infections is essential for HLB management. Therefore, the objective of our study was to determine the effects of systemic insecticides, such as the neonicotinoids imidacloprid, thiamethoxam, and a mixture of thiamethoxam and chlorantraniliprole (diamide) on the probing behavior of CLas-infected D. citri and their effect on CLas transmission. The electrical penetration graph (EPG-DC) technique was used to monitor the stylet penetration activities of CLas-infected D. citri on sweet orange [Citrus sinensis (L.) Osbeck] ‘Valencia’ treated with systemic insecticides. Systemic insecticides disrupted the probing behavior of CLas-infected D. citri, in a way that affected CLas transmission efficiency, particularly by negatively affecting the stylet activities related to the phloem phase. All insecticides reduced (by 57–73%) the proportion of psyllids that exhibited sustainable phloem ingestion (waveform E2 > 10 min), with significant differences observed on plants treated with thiamethoxam and thiamethoxam + chlorantraniliprole. The transmission rate of CLas with high inoculum pressure (five CLas-infected D. citri per plant and a seven-day inoculation access period) to untreated control plants was 93%. In contrast, CLas transmission was reduced to 38.8% when test plants were protected by systemic insecticides. Our results indicated that all insecticides tested presented a potential to reduce CLas inoculation by an average of 59%; therefore, these insecticides can be used to reduce the spread of HLB.
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Affiliation(s)
- Michele Carmo-Sousa
- Fund for Citrus Protection, FUNDECITRUS, Araraquara, São Paulo 14807040, Brazil; (M.C.-S.); (R.B.G.); (N.A.W.)
| | - Rafael Brandão Garcia
- Fund for Citrus Protection, FUNDECITRUS, Araraquara, São Paulo 14807040, Brazil; (M.C.-S.); (R.B.G.); (N.A.W.)
| | - Nelson Arno Wulff
- Fund for Citrus Protection, FUNDECITRUS, Araraquara, São Paulo 14807040, Brazil; (M.C.-S.); (R.B.G.); (N.A.W.)
| | - Alberto Fereres
- Spanish National Research Council, CSIC, 28006 Madrid, Spain;
| | - Marcelo Pedreira Miranda
- Fund for Citrus Protection, FUNDECITRUS, Araraquara, São Paulo 14807040, Brazil; (M.C.-S.); (R.B.G.); (N.A.W.)
- Correspondence: ; Tel.: +55-16-3301-7025
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28
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Gene silencing of Diaphorina citri candidate effectors promotes changes in feeding behaviors. Sci Rep 2020; 10:5992. [PMID: 32265528 PMCID: PMC7138822 DOI: 10.1038/s41598-020-62856-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 03/12/2020] [Indexed: 12/22/2022] Open
Abstract
Insect effectors are mainly secreted by salivary glands, modulate plant physiology and favor the establishment and transmission of pathogens. Feeding is the principal vehicle of transmission of Candidatus Liberibacter asiaticus (Ca. Las) by the Asian citrus psyllid (ACP), Diaphorina citri. This study aimed to predict putative ACP effectors that may act on the Huanglongbing (HLB) pathosystem. Bioinformatics analysis led to the identification of 131 candidate effectors. Gene expression investigations were performed to select genes that were overexpressed in the ACP head and modulated by Ca. Las. To evaluate the actions of candidate effectors on D. citri feeding, six effectors were selected for gene silencing bioassays. Double-stranded RNAs (dsRNAs) of the target genes were delivered to D. citri adults via artificial diets for five days. RNAi silencing caused a reduction in the ACP lifespan and decreased the salivary sheath size and honeydew production. Moreover, after dsRNA delivery of the target genes using artificial diet, the feeding behaviors of the insects were evaluated on young leaves from citrus seedlings. These analyses proved that knockdown of D. citri effectors also interfered with ACP feeding abilities in planta, causing a decrease in honeydew production and reducing ACP survival. Electrical penetration graph (EPG) analysis confirmed the actions of the effectors on D. citri feeding behaviors. These results indicate that gene silencing of D. citri effectors may cause changes in D. citri feeding behaviors and could potentially be used for ACP control.
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Feeding Behavior of Asian Citrus Psyllid [ Diaphorina citri (Hemiptera: Liviidae)] Nymphs and Adults on Common Weeds Occurring in Cultivated Citrus Described Using Electrical Penetration Graph Recordings. INSECTS 2020; 11:insects11010048. [PMID: 32284515 PMCID: PMC7023154 DOI: 10.3390/insects11010048] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 11/30/2022]
Abstract
Asian citrus psyllid, Diaphorina citri, transmits Candidatus Liberibacter asiaticus (CLas), the putative causal agent of Huanglongbing disease. Although they primarily feed on the phloem of Citrus and related plants, when grove or host conditions are unfavorable, D. citri may be able to use weed species as alternate food sources for survival. To explore this possibility, electrical penetration graph (EPG) recordings (18 h) were performed to investigate the feeding behavior of psyllid adults and nymphs on three common south Florida weeds (Bidens alba, Eupatorium capillifolium, and Ludwigia octovalvis). EPG recordings revealed that the proportion of time spent by D. citri feeding on xylem was similar on all tested weed species (19%–22%) and on the positive control (20%), the preferred host, Citrus macrophylla. Very little to no phloem feeding was observed on weed species by either nymphs or adults. Histological studies using epifluorescence microscopy showed that salivary sheaths were branched and extended into xylem of weed species, whereas they ended in phloem on citrus plants. No choice behavioral assays showed that adults can obtain some nutrition by feeding on weed species (xylem feeding) and they may be able to survive on them for short intervals, when host conditions are unfavorable.
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30
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Ammar ED, Achor D, Levy A. Immuno-Ultrastructural Localization and Putative Multiplication Sites of Huanglongbing Bacterium in Asian Citrus Psyllid Diaphorina citri. INSECTS 2019; 10:insects10120422. [PMID: 31771154 PMCID: PMC6955907 DOI: 10.3390/insects10120422] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 11/16/2022]
Abstract
Huanglongbing, the most destructive citrus disease worldwide, is caused by the bacterium 'Candidatus Liberibacter asiaticus' (CLas) and is vectored by the Asian citrus psyllid (ACP). Very little is known about the form and distribution of CLas in infected psyllids, especially at the ultrastructural level. Here, we examined these aspects by transmission electron microscopy, combined with immunogold labeling. In CLas-exposed ACP adults, the CLas bacterial cells were found to be pleomorphic taking tubular, spherical, or flask-shaped forms, some of which seemed to divide further. Small or large aggregates of CLas were found in vacuolated cytoplasmic pockets of most ACP organs and tissues examined, including the midgut, filter chamber, hindgut, Malpighian tubules, and secretory cells of the salivary glands, in addition to fat tissues, epidermis, muscle, hemocytes, neural tissues, bacteriome, and walls of the female spermatheca and oviduct. Large aggregates of CLas were found outside the midgut within the filter chamber and between the sublayers of the basal lamina of the hindgut and Malpighian tubules. Novel intracytoplasmic structures that we hypothesized as 'putative CLas multiplication sites' were found in the cells of the midgut, salivary glands, and other tissues in CLas-exposed ACP. These structures, characterized by containing a granular matrix and closely packed bacterial cells, were unbound by membranes and were frequently associated with rough endoplasmic reticulum. Our results point to the close association between CLas and its psyllid vector, and provide support for a circulative-propagative mode of transmission.
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Affiliation(s)
- El-Desouky Ammar
- Agriculture Research Service, -United States Department of Agriculture (ARS-USDA), Fort Pierce, FL 34945, USA;
| | - Diann Achor
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA;
| | - Amit Levy
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850, USA;
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA
- Correspondence:
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31
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The Probing Behavior Component of Disease Transmission in Insect-Transmitted Bacterial Plant Pathogens. INSECTS 2019; 10:insects10070212. [PMID: 31331012 PMCID: PMC6681269 DOI: 10.3390/insects10070212] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/08/2019] [Accepted: 07/15/2019] [Indexed: 11/16/2022]
Abstract
Insects can be effective vectors of plant diseases and this may result in billions of dollars in lost agricultural productivity. New, emerging or introduced diseases will continue to cause extensive damage in afflicted areas. Understanding how the vector acquires the pathogen and inoculates new hosts is critical in developing effective management strategies. Management may be an insecticide applied to kill the vector or a host plant resistance mechanism to make the host plant less suitable for the vector. In either case, the tactic must act before the insect performs the key behavior(s) resulting in either acquisition or transmission. This requires knowledge of the timing of behaviors the insect uses to probe the plant and commence ingestion. These behaviors are visualized using electropenetrography (EPG), wherein the plant and insect become part of an electrical circuit. With the tools to define specific steps in the probing process, we can understand the timing of acquisition and inoculation. With that understanding comes the potential for more relevant testing of management strategies, through insecticides or host plant resistance. The primary example will be Candidatus Liberibacter asiaticus transmitted by Diaphorina citri Kuwayama in the citrus agroecosystem, with additional examples used as appropriate.
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Lu ZJ, Zhou CH, Yu HZ, Huang YL, Liu YX, Xie YX, Wang J, Hu W, Huang AJ, Su HN, Yang C. Potential roles of insect Tropomyosin1-X1 isoform in the process of Candidatus Liberibacter asiaticus infection of Diaphorina citri. JOURNAL OF INSECT PHYSIOLOGY 2019; 114:125-135. [PMID: 30817914 DOI: 10.1016/j.jinsphys.2019.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 02/25/2019] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is the transmitting vector of Candidatus Liberibacter asiaticus (CLas), which causes citrus disease Huanglongbing (HLB). In recent years, control of HLB has been achieved by reducing the vector population. In the present study, we identified an isoform of D. citri tropomyosin (herein designated as DcTm1-X1). DcTm1-X1 was down-regulated in CLas-infected ACPs compared with uninfected ACPs. Bioinformatics analysis revealed that the full-length DcTm1-X1 is 2955 bp and encodes a protein of 284 amino acids with a deduced molecular weight of 32.15 kDa. Phylogenetic tree analysis suggested that DcTm1-X1 shares a high amino acid identity with its homolog in Acyrthosiphon pisum. Higher DcTm1-X1 expression levels were found in the leg of the psyllid by reverse transcription quantitative PCR (RT-qPCR). According to Blue Native PAGE analysis and mass spectrometric analysis, DcTm1-X1 interacts with citrate synthase (CS) and V-type proton ATPase subunit B-like (VAT). In addition, knockdown of DcTm1-X1 by RNA interference (RNAi) significantly increased the mortality rate of nymphs and the infection rate of CLas at different time points. Taken together, our results show that DcTm1-X1 might play an important role in response to CLas, but also lay a foundation for further research on the functions of DcTm1-X1.
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Affiliation(s)
- Zhan-Jun Lu
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China
| | - Cheng-Hua Zhou
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China
| | - Hai-Zhong Yu
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China.
| | - Yu-Ling Huang
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China
| | - Ying-Xue Liu
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China; Dayu Middle School, Ganzhou, China
| | - Yan-Xin Xie
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China
| | - Jie Wang
- Anhui Agricultural University, Hefei, China
| | - Wei Hu
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China
| | - Ai-Jun Huang
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China
| | - Hua-Nan Su
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China
| | - Chao Yang
- National Navel Orange Engineering and Technology Research Center, Gannan Normal University, Ganzhou, China
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George J, Shi Q, Stelinski LL, Stover E, Lapointe SL. Host Selection, Oviposition and Feeding by a Phytopathogen Vector, Diaphorina citri (Hemiptera: Liviidae), Modulated by Plant Exposure to Formic Acid. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Langdon KW, Ebert TA, Rogers ME. Evaluating the Effect of Imidacloprid Administered in Artificial Diet on Feeding Behavior of Diaphorina citri (Hemiptera: Liviidae) Using Electropenetrography. JOURNAL OF ECONOMIC ENTOMOLOGY 2019; 112:644-652. [PMID: 30602019 PMCID: PMC6427034 DOI: 10.1093/jee/toy400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Indexed: 06/09/2023]
Abstract
The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae) is the vector of Candidatus Liberibacter asiaticus (CLas), the presumed cause of Huanglongbing (HLB) in citrus. Management strategies were developed in Florida that used soil-applied neonicotinoids to protect young trees. Despite the implementation of intense management programs, infection spread among the most intensively managed groves. We used electopenetrography to test five imidacloprid doses (0.55, 5.5, 55, 550, and 5,500 ppm) administered in artificial diet to approximate the dosage required to reduce feeding activity and prevent salivation/ingestion activity. We failed to detect a significant effect of 0.55 ppm imidacloprid on probing behavior, pathway, or salivation/ingestion activity when compared with the untreated control. We observed a significant reduction in the number of probes and the number of pathway with both 5.5 and 55 ppm imidacloprid. We detected a significant reduction in the number of salivation/ingestion events at both 5.5 ppm and 55 ppm imidacloprid (57 and 54 percent, respectively) compared with the untreated control, and a reduction in number of sustained (>600 s) salivation/ingestion at 55 ppm. While reductions in feeding activity were apparent at dosages of at least 5.5 ppm, we were unable to prevent salivation/ingestion with dosages as high as 5,500 ppm, which is greater than what is known to occur following application in the field. While soil-applied imidacloprid may slow the spread of CLas, our findings suggest that prevention of CLas inoculation in the field is unlikely. Management strategies must be refined to prevent the spread of HLB in Florida.
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Affiliation(s)
| | - T A Ebert
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL
| | - M E Rogers
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL
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Killiny N, Jones SE. Metabolic alterations in the nymphal instars of Diaphorina citri induced by Candidatus Liberibacter asiaticus, the putative pathogen of huanglongbing. PLoS One 2018; 13:e0191871. [PMID: 29370262 PMCID: PMC5785020 DOI: 10.1371/journal.pone.0191871] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/12/2018] [Indexed: 11/24/2022] Open
Abstract
Currently, huanglongbing is the most damaging disease of citrus causing huge economic losses. The disease is caused by the Gram-negative bacterium Candidatus Liberibacter asiaticus (CLas). The pathogen is transmitted in a persistent propagative circulative manner within its vector, the Asian citrus psyllid, Diaphorina citri. Exploring the metabolic alteration in the vector may lead to a better understanding of the nutritional needs of CLas and to designing an artificial medium for culturing the pathogen. It has been shown that the nymphal stages have a greater role in transmission mainly because they feed on plants more actively than adults. In this study, we carried out an untargeted comparative metabolomic analysis for healthy and CLas-infected 4th / 5th instar nymphs. The metabolic analysis was performed using trimethylsilylation and methyl chloroformate derivatization followed by Gas Chromatography-Mass Spectrometry (GC-MS). Overall, the changes in the nymph metabolism due to the infection with CLas were more pronounced than in adults, as we previously published. Nymphs reared on CLas-infected Valencia sweet orange were higher in many metabolites, mainly those of the TCA cycle, C16 and C18 fatty acids, glucose, sucrose, L-proline, L-serine, pyroglutamic acid, saccharic acid, threonic acid and myo-inositol than those reared on healthy plants. In contrast, CLas-infected nymphs were lower in putrescine, glycine, L -phenylalanine, L -tyrosine, L -valine, and chiro-inositol. The information provided from this study may contribute in acceleration of the availability of CLas in culture and consequent screening of antibacterial compounds to discover a definitive solution for huanglongbing.
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Affiliation(s)
- Nabil Killiny
- Citrus Research and Education Center, Department of Plant Pathology, IFAS, University of Florida, Lake Alfred, Florida, United States of America
| | - Shelley E Jones
- Citrus Research and Education Center, Department of Plant Pathology, IFAS, University of Florida, Lake Alfred, Florida, United States of America
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