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1.
Int J Biol Macromol ; : 135528, 2024 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-39278448

RESUMEN

Citrus Huanglongbing (HLB) poses an enormous challenge to Citrus cultivation worldwide, necessitating groundbreaking interventions beyond conventional pharmaceutical methods. In this study, we propose molybdenum disulfide-chitosan nanoparticles (MoS2-CS NPs) through electrostatic adsorption, preserving the plant-beneficial properties of molybdenum disulfide (MoS2), while enhancing its antibacterial effectiveness through chitosan modification. MoS2-CS NPs exhibited significant antibacterial efficacy against RM1021, and the closest relatives to Candidatus Liberibacter asiaticus (CLas), Erwinia carotovora, and Xanthomonas citri achieved survival rates of 7.40 % ±â€¯1.74 %, 8.94 % ±â€¯1.40 %, and 6.41 % ±â€¯0.56 %, respectively. In vivo results showed, CLas survival rate of 10.42 % ±â€¯3.51 %. Furthermore, treatment with MoS2-CS NPs resulted in an increase in chlorophyll and carotenoid content. Concomitantly, a significant reduction in malondialdehyde (MDA), soluble sugar, hydrogen peroxide (H2O2), and starch contents was also observed. Mechanistically, MoS2-CS NPs enhanced the activity of antioxidant-related enzymes by upregulating the expression of antioxidant genes, thereby galvanizing the antioxidant system to alleviate oxidative stress. Collectively, this dual functionality-combining direct antibacterial action with the activation of plant defense mechanisms-marks a promising strategy for managing Citrus Huanglongbing and suggests potential agricultural applications for MoS2-based antibacterial treatments.

2.
Microbiol Resour Announc ; : e0060224, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39254041

RESUMEN

We report the draft genome assembly, annotation, and phylogenetic placement of 13 Bacillus spp. isolates isolated from citrus groves under high (Florida) or low (California) Huanglongbing disease pressure.

3.
Plant Dis ; 2024 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-39146002

RESUMEN

Citrus Huanglongbing (HLB) is caused by the phloem-limited α-proteobacterium "Candidatus Liberibacter spp.", among which "Ca. Liberibacter africanus" (CLaf) have posed a significant threat to citrus production in Africa near a century. CLaf is closely related to the globally prevalent "Ca. Liberibacter asiaticus" (CLas), whereas little is known about the virulence of CLaf, primarily due to limited genome resources. In this study, we completed the whole-genome assembly and annotation of CLaf strain Zim (from Zimbabwe). Compared to CLas, a total of 102 CLaf unique genes were identified, including 14 potential Sec-dependent effectors (SDEs) genes, 29 phage-associated genes, and 59 genes with hypothetical function. Among 14 SDEs, V9J15_03810 was able to induce a significant hypersensitive response (HR) in Nicotiana benthamiana, indicating its potential as a virulence factor for CLaf. Genome analysis showed that CLaf strain Zim genome harbored a complete prophage region (named P-Zim-1, 42,208 bp). P-Zim-1 retained two immunosuppressive peroxidase genes (V9J15_02125 and V9J15_02130) homologous to CLas prophage SC1/SC2, whereas the lysogen-associated genes encoding integrase (V9J15_01970) and repressor (V9J15_02080) were homologous to the prophage of "Ca. Liberibacter solanacearum", the causal agent of potato zebra chip disease. In addition, P-Zim-1 carried a novel CRISPR/Cas system, including a CRISPR array (located within V9J15_02040, ranging from 443,643 to 443,897) and five CRISPR-related Cas proteins (V9J15_02005, 02010, 02015, 02025 and 02035). This study first characterized the unique genomic feature of CLaf related to virulence and prophage, which will facilitate future research on CLaf biology and African HLB management.

4.
Mol Plant Pathol ; 25(9): e70002, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39215961

RESUMEN

Citrus huanglongbing (HLB) has been causing enormous damage to the global citrus industry. As the main causal agent, 'Candidatus Liberibacter asiaticus' (CLas) delivers a set of effectors to modulate host responses, while the modes of action adopted remain largely unclear. Here, we demonstrated that CLIBASIA_00185 (CLas0185) could attenuate reactive oxygen species (ROS)-mediated cell death in Nicotiana benthamiana. Transgenic expression of CLas0185 in Citrus sinensis 'Wanjincheng' enhanced plant susceptibility to CLas. We found that methionine sulphoxide reductase B1 (CsMsrB1) was targeted by the effector, and its abundance was elevated in CLas0185-transgenic citrus plants. Their interaction promoted CLas proliferation. We then determined that CsMsrB1 sustained redox state and enzymatic activity of ascorbate peroxidase 1 (CsAPX1) under oxidative stress. The latter reduced H2O2 accumulation and was associated with host susceptibility to CLas infection. Consistently, citrus plants expressing CLas0185 and CsMsrB1 conferred enhanced APX activity and decreased H2O2 content. Taken together, these findings revealed how CLas0185 benefits CLas colonization by targeting CsMsrB1, which facilitated the antioxidant activity and depressed ROS during pathogen infection.


Asunto(s)
Ascorbato Peroxidasas , Citrus sinensis , Metionina Sulfóxido Reductasas , Enfermedades de las Plantas , Enfermedades de las Plantas/microbiología , Citrus sinensis/microbiología , Ascorbato Peroxidasas/metabolismo , Metionina Sulfóxido Reductasas/metabolismo , Metionina Sulfóxido Reductasas/genética , Especies Reactivas de Oxígeno/metabolismo , Plantas Modificadas Genéticamente , Nicotiana/microbiología , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Rhizobiaceae/fisiología , Peróxido de Hidrógeno/metabolismo , Liberibacter , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética
5.
Sensors (Basel) ; 24(14)2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-39065846

RESUMEN

Given the severe impact of Citrus Huanglongbing on orchard production, accurate detection of the disease is crucial in orchard management. In the natural environments, due to factors such as varying light intensities, mutual occlusion of citrus leaves, the extremely small size of Huanglongbing leaves, and the high similarity between Huanglongbing and other citrus diseases, there remains an issue of low detection accuracy when using existing mainstream object detection models for the detection of citrus Huanglongbing. To address this issue, we propose YOLO-EAF (You Only Look Once-Efficient Asymptotic Fusion), an improved model based on YOLOv8n. Firstly, the Efficient Multi-Scale Attention Module with cross-spatial learning (EMA) is integrated into the backbone feature extraction network to enhance the feature extraction and integration capabilities of the model. Secondly, the adaptive spatial feature fusion (ASFF) module is used to enhance the feature fusion ability of different levels of the model so as to improve the generalization ability of the model. Finally, the focal and efficient intersection over union (Focal-EIOU) is utilized as the loss function, which accelerates the convergence process of the model and improves the regression precision and robustness of the model. In order to verify the performance of the YOLO-EAF method, we tested it on the self-built citrus Huanglongbing image dataset. The experimental results showed that YOLO-EAF achieved an 8.4% higher precision than YOLOv8n on the self-built dataset, reaching 82.7%. The F1-score increased by 3.33% to 77.83%, and the mAP (0.5) increased by 3.3% to 84.7%. Through experimental comparisons, the YOLO-EAF model proposed in this paper offers a new technical route for the monitoring and management of Huanglongbing in smart orange orchards.


Asunto(s)
Algoritmos , Citrus , Enfermedades de las Plantas , Citrus/microbiología , Enfermedades de las Plantas/microbiología , Hojas de la Planta/microbiología
6.
Front Cell Infect Microbiol ; 14: 1408362, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38938879

RESUMEN

The Asian citrus psyllid (ACP) Diaphorina citri Kuwayama is the leading vector of Candidatus Liberibacter asiaticus (CLas), the causative agent of citrus Huanglongbing (HLB) disease. The distribution and dynamics of CLas within ACP are critical to understanding how the transmission, spread and infection of CLas occurs within its host vector in nature. In this study, the distribution and titer changes of CLas in various tissues of ACP 5th instar nymphs and adults were examined by fluorescence in situ hybridization (FISH) and real-time quantitative PCR (qPCR) techniques. Results demonstrated that 100% of ACP 5th instar nymphs and adults were infected with CLas following feeding on infected plants, and that CLas had widespread distribution in most of the tissues of ACP. The titers of CLas within the midgut, salivary glands and hemolymph tissues were the highest in both 5th instar nymphs and adults. When compared with adults, the titers of CLas in these three tissues of 5th instar nymphs were significantly higher, while in the mycetome, ovary and testes they were significantly lower than those of adults. FISH visualization further confirmed these findings. Dynamic analysis of CLas demonstrated that it was present across all the developmental ages of ACP adults. There was a discernible upward trend in the presence of CLas with advancing age in most tissues of ACP adults, including the midgut, hemolymph, salivary glands, foot, head, cuticula and muscle. Our findings have significant implications for the comprehensive understanding of the transmission, dissemination and infestation of CLas, which is of much importance for developing novel strategies to halt the spread of CLas, and therefore contribute to the efficient prevention and control of HLB.


Asunto(s)
Citrus , Hemípteros , Hibridación Fluorescente in Situ , Insectos Vectores , Ninfa , Enfermedades de las Plantas , Animales , Hemípteros/microbiología , Insectos Vectores/microbiología , Enfermedades de las Plantas/microbiología , Ninfa/microbiología , Citrus/microbiología , Rhizobiaceae/genética , Rhizobiaceae/fisiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Glándulas Salivales/microbiología , Hemolinfa/microbiología
7.
Plants (Basel) ; 13(11)2024 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-38891269

RESUMEN

Huanglongbing (HLB) is a severe citrus disease worldwide. Wild Australian limes like Citrus australasica, C. inodora, and C. glauca possess beneficial HLB resistance traits. Individual trees of the three taxa were extensively used in a breeding program for over a decade to introgress resistance traits into commercial-quality citrus germplasm. We generated high-quality, phased, de novo genome assemblies of the three Australian limes using PacBio long-read sequencing. The genome assembly sizes of the primary and alternate haplotypes were determined for C. australasica (337 Mb/335 Mb), C. inodora (304 Mb/299 Mb), and C. glauca (376 Mb/379 Mb). The nine chromosome-scale scaffolds included 86-91% of the genome sequences generated. The integrity and completeness of the assembled genomes were estimated to be at 97.2-98.8%. Gene annotation studies identified 25,461 genes in C. australasica, 27,665 in C. inodora, and 30,067 in C. glauca. Genes belonging to 118 orthogroups were specific to Australian lime genomes compared to other citrus genomes analyzed. Significantly fewer canonical resistance (R) genes were found in C. inodora and C. glauca (319 and 449, respectively) compared to C. australasica (576), C. clementina (579), and C. sinensis (651). Similar patterns were observed for other gene families associated with potential HLB resistance, including Phloem protein 2 (PP2) and Callose synthase (CalS) genes predicted in the Australian lime genomes. The genomic information on Australian limes developed in the present study will help understand the genetic basis of HLB resistance.

8.
Insect Sci ; 2024 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-38881212

RESUMEN

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.

9.
Mol Biotechnol ; 2024 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-38940979

RESUMEN

Huanglongbing (HLB), a global citrus threat, is transmitted by Diaphorina citri Kuwayama, a widespread insect pest. The disease's rapid spread and incurability necessitate efficient, sustainable control strategies. This study investigates heat shock protein 70 (HSP70) genes in D. citri, known to play a pivotal role in insect survival and stress response. The genome-wide identification, gene structure analysis, and conserved protein domain analysis of 22 HSP70 genes in D. citri were performed. Furthermore, the expression of these genes during HLB infection or developmental processes was gauged. Phylogenetic analysis revealed the functional categorization of the identified genes, while gene structure and conserved motifs offered insights into gene function. The expression analysis unveiled dynamic profiles in response to infection and across development stages, potentially aiding future targeted pest control strategies. These findings offer promising leads for the design of novel inhibitors or RNAi strategies targeting D. citri and HLB.

10.
Pest Manag Sci ; 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38843443

RESUMEN

BACKGROUND: Asian citrus psyllid, Diaphorina citri, is a hemipteran that vectors the causal pathogen of citrus greening disease, or huanglongbing (HLB). HLB is a tree killing disease that has severely limited citrus production globally. Unfortunately, there is no cure for this disease, and mitigation depends on multiple insecticide applications to reduce vector populations. Silencing of cytochrome P450 expression associated with detoxification enzymes by RNA interference is known to increase susceptibility of D. citri to insecticides. However, dsRNA was previously introduced into psyllids by topical applications. The possible application of this technology for pest management will require effective field delivery of the dsRNA. Therefore, we evaluated a virus vector (Citrus tristeza virus; 'mild strain' T36) to deliver gene silencing directly to this sap-sucking insect via plant phloem. Citrus macrophylla plants inoculated with CTV expressing a truncated consensus sequence of CYP450 (CTV-tCYP450) constantly produced small interfering RNA in the plant phloem that targeted five cytochrome p540 (CYP450) genes in D. citri. RESULTS: Insecticide susceptible D. citri reared on citrus infected with CTV-tCYP450 were subsequently more susceptible to imidacloprid, fenpropathrin, carbaryl, and chlorpyrifos than those reared on citrus infected with wildtype CTV or non-infected negative controls. Additionally, nymph survival and adult lifespan were significantly reduced when psyllids were reared on CTV-tCYP450 citrus plants compared with controls. Interestingly, similar results were obtained after one and two generations of rearing. Finally, field-collected psyllids from areas with known broad-spectrum insecticide resistance were rendered more susceptible to imidacloprid and fenpropathrin after feeding on CTV-tCYP450 citrus trees as compared with those reared on controls. CONCLUSION: The integration of citrus-mediated RNA inference targeting psyllid detoxification enzymes could function as a resistance management tool and reduce insecticide input in an integrated pest management program for HLB. © 2024 Society of Chemical Industry.

11.
J Invertebr Pathol ; 204: 108122, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38710321

RESUMEN

The Asian citrus psyllid (ACP) Diaphorina citri transmits the causative agent of huanglongbing, or citrus greening disease, that has decimated global citrus production. Pesticidal proteins derived from bacteria such as Bacillus thuringiensis (Bt) can provide effective and environmentally friendly alternatives for management of D. citri, but few with sufficient toxicity to D. citri have been identified. Here, we report on the toxicity of 14 Bt-derived pesticidal proteins from five different structural groups against D. citri. These proteins were selected based on previously reported toxicity to other hemipteran species and on pesticidal protein availability. Most of the proteins were expressed in Escherichia coli and purified from inclusion bodies or His-tag affinity purification, while App6Aa2 was expressed in Bt and purified from spore/crystal mixtures. Pesticidal proteins were initially screened by feeding psyllids on a single dose, and lethal concentration (LC50) then determined for proteins with significantly greater mortality than the buffer control. The impact of CLas infection of D. citri on toxicity was assessed for selected proteins via topical feeding. The Bt protein Tpp78Aa1 was toxic to D. citri adults with an LC50 of approximately 204 µg/mL. Nymphs were more susceptible to Tpp78Aa1 than adults but no significant difference in susceptibility was observed between healthy and CLas-infected nymphs or adults. Tpp78Aa1 and other reported D. citri-active proteins may provide valuable tools for suppression of D. citri populations.


Asunto(s)
Proteínas Bacterianas , Hemípteros , Control Biológico de Vectores , Animales , Hemípteros/microbiología , Citrus/microbiología , Insectos Vectores , Bacillus thuringiensis/química , Enfermedades de las Plantas/microbiología , Insecticidas
12.
J Econ Entomol ; 117(4): 1356-1366, 2024 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-38728437

RESUMEN

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a major pest of citrus due to its role as the vector of the bacterium that causes huanglongbing. In commercial citrus, ACP control currently relies on the application of insecticides, which may not be sustainable long-term, nor practical in urban areas. The sterile insect technique (SIT) is an alternative strategy in which large numbers of pests are reared, sterilized using radiation, and then released into the field to compete with wild individuals for matings, suppressing population growth. As a fundamental step toward the development of SIT for ACP, this study sought to identify the optimum radiation dose required to sterilize ACP without affecting their survival and mating capacity. Virgin adult ACP of both sexes were subjected to doses of X-ray irradiation ranging from 40 to 480 Gy, then paired with a nonirradiated mate and allowed to produce offspring. Fecundity was estimated as the number of eggs laid, and fertility as the proportion of those eggs that hatched. Females were more radio-sensitive than males, exhibiting a major drop in fecundity at even the lowest dose and 100% sterility at 80 Gy. In contrast, a fivefold higher dose (400 Gy) did not achieve complete sterility in males, with around 5% offspring survival. However, F1 progeny of males exposed to 320 Gy or higher were subsequently found to be 100% sterile. This confirmation of inherited sterility suggests that balancing the sterilizing effects of radiation against its mortality-inducing effects may warrant further evaluation.


Asunto(s)
Fertilidad , Hemípteros , Animales , Femenino , Fertilidad/efectos de la radiación , Masculino , Control Biológico de Vectores , Rayos X , Longevidad , Citrus , Control de Insectos/métodos
13.
Insects ; 15(5)2024 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-38786919

RESUMEN

Trioza erytreae (Del Guercio, 1918) (Hemiptera: Triozidae) is a citrus pest which produces gall symptoms on leaves and transmits bacteria associated with the citrus disease Huanglongbing, 'Candidatus Liberibacter' spp. In the present work, the biology and behaviour of T. erytreae were studied in different rootstock-cultivar combinations. Six rootstocks were used, Flying dragon (FD), 'Cleopatra' mandarin (CL), Carrizo citrange (CC), Forner-Alcaide no.5 (FA5), Forner-Alcaide no.517 (FA517) and Citrus macrophylla (CM), and six scion cultivars: 'Star Ruby', 'Clemenules', 'Navelina', 'Valencia Late', 'Fino 49' and 'Ortanique'. Survival and oviposition were evaluated in a no-choice trial, and preference in a choice trial, all of them under greenhouse conditions. Trioza erytreae did not show a clear settle preference for any citrus combination. However, it was able to lay more eggs in 'Fino 49' grafted on CC than on FD. In terms of survival, 'Ortanique' grafted onto FA5 was more suitable than when grafted onto FA517, and in the case of 'Valencia Late', when it was grafted onto CM rather than CC. Our results showed that T. erytreae behave differently depending on the citrus combination.

14.
Int J Mol Sci ; 25(10)2024 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-38791176

RESUMEN

Extensive microbial interactions occur within insect hosts. However, the interactions between the Huanglongbing (HLB) pathogen and endosymbiotic bacteria within the Asian citrus psyllid (ACP, Diaphorina citri Kuwayama) in wild populations remain elusive. Thus, this study aimed to detect the infection rates of HLB in the ACP across five localities in China, with a widespread prevalence in Ruijin (RJ, 58%), Huidong (HD, 28%), and Lingui (LG, 15%) populations. Next, microbial communities of RJ and LG populations collected from citrus were analyzed via 16S rRNA amplicon sequencing. The results revealed a markedly higher microbial diversity in the RJ population compared to the LG population. Moreover, the PCoA analysis identified significant differences in microbial communities between the two populations. Considering that the inter-population differences of Bray-Curtis dissimilarity in the RJ population exceeded those between populations, separate analyses were performed. Our findings indicated an increased abundance of Enterobacteriaceae in individuals infected with HLB in both populations. Random forest analysis also identified Enterobacteriaceae as a crucial indicator of HLB infection. Furthermore, the phylogenetic analysis suggested a potential regulatory role of ASV4017 in Enterobacteriaceae for ACP, suggesting its possible attractant activity. This research contributes to expanding the understanding of microbial communities associated with HLB infection, holding significant implications for HLB prevention and treatment.


Asunto(s)
Enterobacteriaceae , Hemípteros , Filogenia , Enfermedades de las Plantas , ARN Ribosómico 16S , Animales , Hemípteros/microbiología , Enterobacteriaceae/genética , Enterobacteriaceae/clasificación , Enterobacteriaceae/patogenicidad , ARN Ribosómico 16S/genética , Enfermedades de las Plantas/microbiología , China/epidemiología , Citrus/microbiología , Microbiota
15.
Sci Rep ; 14(1): 12183, 2024 05 28.
Artículo en Inglés | MEDLINE | ID: mdl-38806617

RESUMEN

The fabrication of the first label-free electrochemical DNA probe biosensor for highly sensitive detection of Candidatus Liberibacter asiaticus (CLas), as the causal agent of citrus huanglongbing disease, is conducted here. An OMP probe was designed based on the hybridization with its target-specific sequence in the outer membrane protein (OMP) gene of CLas. The characterization of the steps of biosensor fabrication and hybridization process between the immobilized OMP-DNA probe and the target ssDNA oligonucleotides (OMP-complementary and three mismatches OMP or OMP-mutation) was monitored using cyclic voltammetry and electrochemical impedance spectroscopy based on increasing or decreasing in the electron transfer in [Fe (CN)6]3-/4- on the modified gold electrode surface. The biosensor sensitivity indicated that the peak currents were linear over ranges from 20 to 100 nM for OMP-complementary with the detection limit of 0.026 nM (S/N = 3). The absence of any cross-interference with other biological DNA sequences confirmed a high selectivity of fabricated biosensor. Likewise, it showed good specificity in discriminating the mutation oligonucleotides from complementary target DNAs. The functional performance of optimized biosensor was achieved via the hybridization of OMP-DNA probe with extracted DNA from citrus plant infected with CLas. Therefore, fabricated biosensor indicates promise for sensitivity and early detection of citrus huanglongbing disease.


Asunto(s)
Proteínas de la Membrana Bacteriana Externa , Técnicas Biosensibles , Citrus , Sondas de ADN , Técnicas Electroquímicas , Enfermedades de las Plantas , Técnicas Biosensibles/métodos , Citrus/microbiología , Enfermedades de las Plantas/microbiología , Sondas de ADN/genética , Proteínas de la Membrana Bacteriana Externa/genética , Técnicas Electroquímicas/métodos , Electrodos , Hibridación de Ácido Nucleico , Espectroscopía Dieléctrica , Límite de Detección , Rhizobiaceae/genética , Rhizobiaceae/aislamiento & purificación , Liberibacter/genética
16.
J Chem Ecol ; 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38568416

RESUMEN

Fast and effective monitoring and surveillance techniques are crucial for the swift implementation of control methods to prevent the spread of Huanglongbing, a devastating citrus disease, and its invasive psyllid vector, Asian citrus psyllid, Diaphorina citri, into South Africa, as well as to control the native vector, African citrus triozid, Trioza erytreae. Monitoring for citrus psyllid pests can be improved by using semiochemical odorants to augment already visually attractive yellow sticky traps. However, environmental variables such as temperature and humidity could influence odorant release rates. Five field cages were used to test the ability of a selection of odorants to improve yellow sticky trap efficacy in capturing citrus psyllids. Environmental effects on odorant loss from the dispensers were also investigated. The odorants that most improved yellow sticky trap captures in field cages were then tested under open field conditions alongside lower concentrations of those same lures. Gas chromatography-mass spectrometry was used to calculate odorant release rates as well as to determine if any contamination occurred under field conditions. None of the odorants under field cage or field conditions significantly improved psyllid capture on yellow sticky traps. Temperature influenced odorant loss, and release rate from polyethylene bulbs decreased over time. Based on these results, the use of unbaited yellow sticky traps seems to be the most effective method for monitoring of Huanglongbing vectors.

17.
Mol Plant Microbe Interact ; 37(5): 459-466, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38597923

RESUMEN

Citrus Huanglongbing (HLB), which is caused by 'Candidatus Liberibacter asiaticus' (CLas), is one of the most destructive citrus diseases worldwide, and defense-related Citrus sinensis gene resources remain largely unexplored. Calcium signaling plays an important role in diverse biological processes. In plants, a few calcium-dependent protein kinases (CDPKs/CPKs) have been shown to contribute to defense against pathogenic microbes. The genome of C. sinensis encodes dozens of CPKs. In this study, the role of C. sinensis calcium-dependent protein kinases (CsCPKs) in C. sinensis defense was investigated. Silencing of CsCPK6 compromised the induction of defense-related genes in C. sinensis. Expression of a constitutively active form of CsCPK6 (CsCPK6CA) triggered the activation of defense-related genes in C. sinensis. Complementation of CsCPK6 rescued the defense-related gene induction in an Arabidopsis thaliana cpk4/11 mutant, indicating that CsCPK6 carries CPK activity and is capable of functioning as a CPK in Arabidopsis. Moreover, an effector derived from CLas inhibits defense induced by the expression of CsCPK6CA and autophosphorylation of CsCPK6, which suggests the involvement of CsCPK6 and calcium signaling in defense. These results support a positive role for CsCPK6 in C. sinensis defense against CLas, and the autoinhibitory regulation of CsCPK6 provides a potential genome-editing target for improving C. sinensis defense. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Asunto(s)
Citrus sinensis , Regulación de la Expresión Génica de las Plantas , Enfermedades de las Plantas , Proteínas de Plantas , Proteínas Quinasas , Citrus sinensis/genética , Citrus sinensis/microbiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Proteínas Quinasas/metabolismo , Proteínas Quinasas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/microbiología , Arabidopsis/inmunología , Resistencia a la Enfermedad/genética , Liberibacter/genética , Liberibacter/fisiología
18.
Front Plant Sci ; 15: 1369883, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38601304

RESUMEN

Introduction: Heavy metal-associated isoprenylated plant proteins (HIPPs) play vital roles in maintaining heavy metal balance and responding to both biotic and abiotic stresses in vascular plants. However, the role of HIPPs in the response to Huanglongbing (HLB), a harmful disease of citrus caused by the phloem-colonizing bacterium Candidatus Liberibacter asiaticus (CLas), has not been examined. Methods and results: In this study, a total of 26 HIPP genes were identified in Citrus sinensis, and they were grouped into 5 clades. The CsHIPP genes are distributed on 8 chromosomes and exhibited considerable synteny with HIPPs found in Arabidopsis thaliana. Additionally, we analyzed the gene structure, conserved motifs and domains of the CsHIPPs. Various cis-acting elements related to plant hormones and stress responses were identified in the promoters of CsHIPPs. Public transcriptome data and RT-qPCR analysis showed that the expression level of CsHIPP03 was significantly reduced in samples infected by CLas and Xanthomonas citri ssp. citri (Xcc). Furthermore, silencing the homologous gene of CsHIPP03 in Nicotiana benthamiana increased the disease resistance of plants to bacteria. Discussion: Our results provide a basis for functional studies of HIPP gene family in C. sinensis, highlighting their functions in bacterial resistance, and improve our understanding to the susceptibility mechanism of HLB.

19.
Elife ; 132024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38602271

RESUMEN

The bacterium responsible for a disease that infects citrus plants across Asia facilitates its own proliferation by increasing the fecundity of its host insect.


Asunto(s)
Citrus , Hemípteros , Animales , Citrus/microbiología , Plantas , Reproducción , Asia , Enfermedades de las Plantas/microbiología
20.
Foods ; 13(6)2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38540817

RESUMEN

Citri Reticulatae Pericarpium, especially the pericarp of Citrus reticulata Blanco cv. Chachiensis (PCRC), is an important edible and medicinal ingredient for health and pharmacological properties. Citrus Huanglongbing, a devastating disease that currently threatens the citrus industry worldwide, is caused by a phloem-limited alpha-proteobacterium, "Candidatus Liberibacter asiaticus" (CLas). The industry of cultivar Chachiensis has been suffering from HLB. Although HLB affected the quality of citrus fruit, whether the quality of PCRC was affected by HLB remains unclear. In this study, we compared the metabolite profiles between HLB-affected and healthy PCRC from three sources: fresh, 6-month-old, and 9-year-old PCRC, through the untargeted LC-MS method. Compared to healthy controls, various types of bioactive compounds, mainly flavonoids, terpenoids, alkaloids, coumarins, polysaccharides, and phenolic acids, accumulated in HLB-affected PCRC, especially in the HLB-affected 9-year PCRC. In particular, isorhamnetin, isoliquiritigenin, luteolin 7-O-beta-D-glucoside, limonin, geniposide, pyrimidodiazepine, scoparone, chitobiose, m-coumaric acid, malonate, and pantothenic acid, which contributed to the pharmacological activity and health care effects of PCRC, were highly accumulated in HLB-affected 9-year-old PCRC compared to the healthy control. Multibioassay analyses revealed that HLB-affected 9-year-old PCRC had a higher content of total flavonoids and total polyphenols and exhibited similar antioxidant capacity as compared to healthy controls. The results of this study provided detailed information on the quality of HLB-affected PCRC.

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