Article
Physiology
Li-He Zhang, Su-Li Ren, Zheng-Qin Su, Pei-Ping Xu, Da Ou, Li-Jun Wang, Wen Sang, Bao-Li Qiu
Summary: The study revealed that infection by the Asian citrus psyllid-transmitted pathogen Ca. Liberibacter asiaticus significantly affects the contents, proportion, and utilization efficiency of different amino acids in citrus plants, ACP adults, and nymphs, leading to a developmental pattern of ACP that is more conducive to CLas transmission.
FRONTIERS IN PHYSIOLOGY
(2021)
Article
Plant Sciences
Nabil Killiny
Summary: In this study, it was found that the infection of 'Candidatus Liberibacter asiaticus' led to a significant decrease in organic acids in the phloem sap of sweet orange and periwinkle plants. It was hypothesized that bacterial growth induced the mitochondrial tricarboxylic acid cycle to produce these compounds as a carbon source, which may explain the unequal distribution of the bacteria within infected trees.
Article
Infectious Diseases
Faraj Hijaz, Yasser Nehela, Ozgur Batuman, Nabil Killiny
Summary: The study demonstrates the successful measurement of oxytetracycline levels in citrus phloem and xylem saps using the europium method, with or without solid-phase extraction (SPE) cleanup. Samples infected with 'Ca. L. asiaticus' showed higher inhibition of oxytetracycline fluorescence intensity. The visualization under ultraviolet light confirmed the presence of oxytetracycline in citrus saps.
Article
Plant Sciences
Yunuo Liu, Liting Dong, Danlu Ran, Shuai Wang, Rongrong Qu, Lin Zheng, Aihong Peng, Yongrui He, Shanchun Chen, Xiuping Zou
Summary: This study compared the responses of Jincheng orange, kaffir lime, and orange jasmine to Huanglongbing (HLB). It found that orange jasmine displayed the strongest resistance to HLB. Hormone analysis indicated the involvement of salicylic acid, jasmonic acid, and gibberellin in regulating citrus resistance to HLB. Transcriptome analysis revealed differential gene expression patterns in response to HLB infection, with orange jasmine showing stable gene expression levels compared to Jincheng orange and kaffir lime.
JOURNAL OF PLANT GROWTH REGULATION
(2023)
Article
Horticulture
Huaye Xiong, Yayin Luo, Heinz Rennenberg, Jie Wang, Bin Hu, Huanyu Zhao, Xiaodong Tang, Yueqiang Zhang, Xiaojun Shi
Summary: Mature citrus leaves play a central role in carbon and nitrogen metabolism for citrus tree growth. Fruit production and nitrogen supply have significant effects on leaf metabolism, as evidenced by leaf chlorosis on fruiting branches. In this study, citrus trees were grown with low and high nitrogen supplies, and analysis of leaves and phloem sap from fruiting and nonfruiting branches revealed that fruiting stimulates nitrogen allocation and organic nitrogen catabolism. Proline was identified as a key metabolite in mature citrus leaves and phloem sap, with decreased levels due to fruiting. Additionally, nitrogen supply enhanced nitrogen storage and proline turnover in both fruiting and nonfruiting branches. The timing of nitrogen management in orchards is important for optimal fruit development.
SCIENTIA HORTICULTURAE
(2023)
Article
Plant Sciences
Joon Hyuk Suh, Xixuan Tang, Yi Zhang, Frederick G. Gmitter, Yu Wang
Summary: This study used a multiple pathway-targeted metabolomic approach to elucidate the metabolic mechanisms of HLB tolerance in citrus. The findings revealed a pivotal metabolic network associated with HLB tolerance, showing that pathways linked to plant growth, phloem regeneration, and energy-yielding metabolism were upregulated in HLB-tolerant cultivars. Additionally, metabolites related to plant defense responses were decreased in the tolerant group, indicating a strategy of sustaining plant growth and phloem formation rather than direct plant defense against the disease.
FRONTIERS IN PLANT SCIENCE
(2021)
Review
Plant Sciences
Gertrud Lohaus
Summary: This review primarily focuses on the chemical composition of phloem sap obtained by aphid stylectomy to facilitate data comparison.
JOURNAL OF PLANT PHYSIOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Lorena Mara A. Silva, Elenilson G. Alves Filho, Tigressa Helena S. Rodrigues, Francisca Jamila C. Louredo, Guilherme J. Zocolo, Kirley M. Canuto, Sandra B. Mikich, Dieter Liebsch, Adriana De Almeida, Edy S. De Brito
Summary: In commercial pine farms in southern Brazil, black capuchin monkeys cause damage to wood by removing bark from pine trees. This study evaluated the variability of primary metabolites in phloem saps from different pine species and identified compounds that attract or repel monkeys.
JOURNAL OF CHEMICAL ECOLOGY
(2022)
Article
Plant Sciences
Susana A. Dandlen, Jose P. Da Silva, Maria Graca Miguel, Amilcar Duarte, Deborah M. Power, Natalia Tomas Marques
Summary: The susceptibility of Citrus macrophylla (CM) to the severe Citrus tristeza virus (CTV), T36, is higher than that of Citrus aurantium (CA). The impact of host-virus interactions on host physiology remains largely unknown. This study evaluated the metabolite profile and antioxidant activity in the phloem sap of healthy and infected CA and CM plants. The results showed that the antioxidant enzyme activity increased significantly in infected CM plants and decreased in infected CA plants. Furthermore, CTV infection resulted in a drastic reduction in secondary metabolites in CA but not in CM.
Article
Food Science & Technology
Dong-Shin Kim, Sun Lee, Suk Man Park, Su Hyun Yun, Han-Seung Gab, Sang Suk Kim, Hyun-Jin Kim
Summary: The study analyzed 10 citrus varieties to evaluate their chemical profiles and antioxidant activities, finding significant variations in content of sugars, organic acids, flavonoids, limonoids, and carotenoids among different varieties. These differences led to variations in antioxidant capacity and quality parameters. The study provides valuable information for understanding the relationship between citrus quality and metabolite profiles, which can be useful for the development and improvement of new citrus varieties.
Article
Plant Sciences
Fernanda N. C. Vasconcelos, Jinuyn Li, Zhiqian Pang, Christopher Vincent, Nian Wang
Summary: This study quantifies the total population size of 'Candidatus Liberibacter asiaticus' (CLas) in citrus plants and highlights the distribution of CLas cells in different organs, providing insights into the metabolic burden of CLas in various tissues. Additionally, the study estimates the ratios of citrus cells to CLas cells and phloem cells to CLas cells in different plant parts, shedding light on the virulence mechanisms of CLas.
Article
Multidisciplinary Sciences
Christopher Wallis, Zachary T. Gorman, Rachel T. Rattner, Subhas T. Hajeri, Raymond T. Yokomi
Summary: This study reveals the biochemical patterns associated with the severity of CTV infections in citrus plants, which can potentially be used to identify economically relevant CTV infections.
Article
Biochemical Research Methods
Qinglin Li, Hui Xu, Wentao Zhang, Jingjing Sun, Yingchao Yue
Summary: The authors proposed a new method for sampling phloem sap based on capillary-air pressure principle, which showed higher substance quantity and concentration compared to the traditional EDTA method. This new method offers a rapid and simple way for sampling phloem sap, improving the efficiency of studying the nutritional status of cucumber plants during growth.
Article
Food Science & Technology
Jelena Radulovic, Milica Lucic, Aleksandra Nesic, Antonije Onjia
Summary: This study investigated the occurrence of pesticide residues on citrus fruits and evaluated the acute and chronic risk for adults and children. Multiple residues were detected in 83% of the samples analyzed, and 28% contained pesticides at or above maximum residue levels. Most detected pesticides posed a low risk, but some exceeded the acceptable levels for acute and chronic dietary risk. The acute risk was unacceptable in 5.3% of citrus fruits for adults and 26% for children.
Article
Food Science & Technology
Erbao Chen, Huanlu Song, Shuna Zhao, Chen Liu, Long Tang, Yu Zhang
Summary: It was found that the odor compounds differed significantly among brown sugar, muscovado sugar, and brown granulated sugar, with more Maillard reaction products detected in brown sugar. Muscovado sugar, prepared by boiling the mixture for a longer time, showed more efficient Maillard reaction and significantly higher organic acid contents than brown sugar. The separation of molasses during the production of brown granulated sugar resulted in lower odor compound contents compared to brown sugar and muscovado sugar.
LWT-FOOD SCIENCE AND TECHNOLOGY
(2021)
Article
Plant Sciences
Nabil Killiny, Pedro Gonzalez-Blanco, Siddarame Gowda, Xavier Martini, Ed Etxeberria
Summary: A new method utilizing laser treatment for the delivery of dsRNA to citrus leaves allows for the rapid observation of gene function and phenotype response, which is systemic and indicates the movement of RNA within plants. This technique provides a faster and more specific tool for studying gene function in higher plants and trees.
Review
Plant Sciences
Nabil Killiny
Summary: This review discusses the relationship between the citrus greening pathogen 'Ca. L. asiaticus' and its psyllid vector Diaphorina citri. It explores the molecular features of acquisition, growth, and transmission of 'Ca. L. asiaticus' within the psyllid, as well as its effects on the psyllid's energy metabolism, metabolic pathways, immune system, and other physiological impacts. The findings suggest the development of a mutualistic relationship between 'Ca. L. asiaticus' and its vector. This review provides insights for innovative management strategies.
Article
Biochemistry & Molecular Biology
Yasser Nehela, Nabil Killiny
Summary: In this study, it was found that the infection of 'Candidatus Liberibacter asiaticus', the causal agent of Huanglongbing in citrus, led to an increase in endogenous GABA and succinate content, while decreasing ketoglutarate in citrus plants. Three predicted gab genes in the citrus genome were upregulated in response to the infection, and exogenously applied GABA was quickly converted to succinate and fed into the TCA cycle.
MOLECULAR PLANT-MICROBE INTERACTIONS
(2022)
Article
Plant Sciences
Nabil Killiny
Summary: In this study, it was found that the infection of 'Candidatus Liberibacter asiaticus' led to a significant decrease in organic acids in the phloem sap of sweet orange and periwinkle plants. It was hypothesized that bacterial growth induced the mitochondrial tricarboxylic acid cycle to produce these compounds as a carbon source, which may explain the unequal distribution of the bacteria within infected trees.
Article
Plant Sciences
Nabil Killiny
Summary: Volatile organic compounds (VOCs) are lipophilic hydrocarbon compounds produced and released by plants as a defense mechanism. This study provides preliminary evidence for a potential role of carotenoids in supporting the MEP pathway and/or the production of monoterpenes.
Article
Entomology
Nabil Killiny, Craig R. Brodersen
Summary: This study presents a non-destructive method using high-resolution micro-computed X-ray tomography (microCT) to investigate the structure of the anterior gut of the glassy-winged sharpshooter (GWSS). This method eliminates the need for destructive dissection and allows for three-dimensional visualization.
Article
Infectious Diseases
Christopher I. Vincent, Faraj Hijaz, Myrtho Pierre, Nabil Killiny
Summary: This study found that foliar application of oxytetracycline and streptomycin in citrus did not effectively deliver antibiotics, and the use of adjuvants did not change this situation. Compared to foliar application, trunk injection of oxytetracycline resulted in higher levels of the antibiotic in citrus trees and significantly reduced the titer of the HLB pathogen. However, trunk injection of streptomycin had poor effects and did not reduce the pathogen titer.
Article
Entomology
Mahnaz Rashidi, Nabil Killiny
Summary: The immune system of Diaphorina citri is weaker compared to other insects. However, it possesses a complete Toll system. Characterizing Toll signaling system genes and studying gene expression profiles in different life stages can help design innovative strategies for controlling this insect vector.
Article
Plant Sciences
Paula Rios Glusberger, Joseph R. R. Petrone, Alam Munoz-Beristain, Jinyun Li, Nian Wang, Anirban Guha, Christopher Vincent, Nabil Killiny, Eric W. W. Triplett
Summary: Citrus greening disease has rapidly spread across all counties in Florida in the past 20 years, causing devastating economic losses. The disease is caused by the phloem-restricted bacterium 'Candidatus Liberibacter asiaticus' (CLas). Research has shown that citrus plants accumulate free citrate in response to phosphorus deficiency, which may worsen CLas infection. Greenhouse experiments have demonstrated that foliar-sprayed phosphate can reduce levels of free citrate and delay the detection of CLas. Field experiments have also shown that certain phosphate treatments can decrease the severity of CLas infection in mature trees.
PLANT HEALTH PROGRESS
(2023)
Article
Plant Sciences
Poulami Sarkar, Chun-Yi Lin, Jacobo Robledo Buritica, Nabil Killiny, Amit Levy
Summary: Plant bacterial pathogens transmitted by hemipteran vectors are a significant threat to agriculture worldwide. This review focuses on the molecular interactions between circulative bacteria and their insect vectors, as well as the transmission routes and molecular factors that maintain an effective relationship between phloem-limited bacteria and the insect host. Understanding these pathogen-vector relationships at the molecular level is crucial for managing vector-borne bacterial diseases.
Article
Zoology
Abdelaziz Kishk, Clebson dos Santos Tavares, Ruchir Mishra, Bryony C. Bonning, Nabil Killiny
Summary: The Asian citrus psyllid, a vector of citrus greening disease, has developed resistance to chemical insecticides, leading to the need for alternative control methods. This study investigated the impact of the bacterial proteins Mpp51Aa1 and Cry1Ba1 on the infected psyllids and found that they had a greater impact on survival and lifespan compared to healthy psyllids.
JOURNAL OF INVERTEBRATE PATHOLOGY
(2023)
Article
Plant Sciences
Yasser Nehela, Nabil Killiny
Summary: This study used metabolomics and transcriptomics to investigate the role of gamma-aminobutyric acid (GABA) in citrus plants infected with Huanglongbing (HLB) or healthy. The findings suggest that GABA accumulation influences metabolic pathways and antioxidant defense machinery in citrus plants. GABA supplementation showed potential as an alternative eco-friendly strategy against HLB and other diseases in citrus trees.
Article
Plant Sciences
Yasser Nehela, Nabil Killiny
Summary: In this study, the researchers investigated the potential therapeutic role of gamma-aminobutyric acid (GABA) in combating Huanglongbing (HLB) in citrus trees. They found that GABA supplementation increased the accumulation of endogenous GABA in the leaves of healthy and 'Ca. L. asiaticus'-infected trees. This led to the activation of a multi-layered defensive system, modulation of phytohormone levels, and regulation of gene expression, ultimately aiding in the battle against HLB.
Article
Biochemistry & Molecular Biology
Nabil Killiny
Summary: Virus-induced gene silencing is a promising technique for functional genomics studies, with citrus tristeza virus being successfully used to create an infectious clone for silencing endogenous citrus genes. Simultaneously graft-inoculating constructs targeting PDS and ALAD has also been successful.
PLANT SIGNALING & BEHAVIOR
(2022)
Article
Biochemistry & Molecular Biology
Nabil Killiny, Shelley E. Jones, Pedro Gonzalez-Blanco
Summary: The ALAD enzyme is important for the biosynthesis of tetrapyrroles in plants. Silencing the ALAD gene in citrus leads to yellow spots and necrosis in leaves, as well as altered leaf pigments and metabolites. The silencing also causes an increase in stress indicators like total phenolic content, H2O2, and ROS.
PLANT SIGNALING & BEHAVIOR
(2022)
Article
Plant Sciences
Sreelekha Duruvasula, Ulaganathan Kandasamy, Sujatha Mulpuri
Summary: The study identified the MLO gene family in the sunflower genome using computational methods, analyzed their chromosomal distribution, gene structure, and phylogenetic relationship, providing a reference for future functional studies. Additionally, the analysis revealed 12 differentially expressed genes between powdery mildew resistant and susceptible sunflower varieties, further contributing to understanding genetic resistance mechanisms in sunflower.
PHYSIOLOGICAL AND MOLECULAR PLANT PATHOLOGY
(2024)
Article
Plant Sciences
Zainul A. Khan, Damini Diksha, Pooja Thapa, Yazing S. Mailem, Susheel K. Sharma, Nitika Gupta, Gopi Kishan, Santosh Watpade, Virendra K. Baranwal
Summary: This study reported the presence of several viruses, including apple rubbery wood virus 1, apple necrotic mosaic virus, citrus virus A, apple stem grooving virus, apple stem pitting virus, apple chlorotic leaf spot virus, in pear trees in India for the first time. The genomes of these viruses were sequenced and analyzed, revealing the expansion of their host range in pear trees. These findings are of great importance for the biological study of pear viruses and virus indexing programs.
PHYSIOLOGICAL AND MOLECULAR PLANT PATHOLOGY
(2024)
Article
Plant Sciences
Xueren Cao, Qiaohui Han, Jonathan S. West
Summary: Spraying double-stranded RNAs (dsRNA) targeting the genes of E. quercicola can effectively control rubber tree powdery mildew and reduce the expression of pathogen genes as well as the severity of the disease.
PHYSIOLOGICAL AND MOLECULAR PLANT PATHOLOGY
(2024)