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Cao Y, Zhang Q, Liu Y, Yan T, Ding L, Yang Y, Meng Y, Shan W. The RXLR effector PpE18 of Phytophthora parasitica is a virulence factor and suppresses peroxisome membrane-associated ascorbate peroxidase NbAPX3-1-mediated plant immunity. THE NEW PHYTOLOGIST 2024. [PMID: 38877698 DOI: 10.1111/nph.19902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 05/28/2024] [Indexed: 06/16/2024]
Abstract
Phytophthora parasitica causes diseases on a broad range of host plants. It secretes numerous effectors to suppress plant immunity. However, only a few virulence effectors in P. parasitica have been characterized. Here, we highlight that PpE18, a conserved RXLR effector in P. parasitica, was a virulence factor and suppresses Nicotiana benthamiana immunity. Utilizing luciferase complementation, co-immunoprecipitation, and GST pull-down assays, we determined that PpE18 targeted NbAPX3-1, a peroxisome membrane-associated ascorbate peroxidase with reactive oxygen species (ROS)-scavenging activity and positively regulates plant immunity in N. benthamiana. We show that the ROS-scavenging activity of NbAPX3-1 was critical for its immune function and was hindered by the binding of PpE18. The interaction between PpE18 and NbAPX3-1 resulted in an elevation of ROS levels in the peroxisome. Moreover, we discovered that the ankyrin repeat-containing protein NbANKr2 acted as a positive immune regulator, interacting with both NbAPX3-1 and PpE18. NbANKr2 was required for NbAPX3-1-mediated disease resistance. PpE18 competitively interfered with the interaction between NbAPX3-1 and NbANKr2, thereby weakening plant resistance. Our results reveal an effective counter-defense mechanism by which P. parasitica employed effector PpE18 to suppress host cellular defense, by suppressing biochemical activity and disturbing immune function of NbAPX3-1 during infection.
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Affiliation(s)
- Yimeng Cao
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Qiang Zhang
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yuan Liu
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Tiantian Yan
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Liwen Ding
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yang Yang
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yuling Meng
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Weixing Shan
- State Key Laboratory for Crop Stress Resistance and High-Efficiency Production, and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, China
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Li Y, Ma R, Gao C, Li Z, Zheng Y, Fang F, Wang C, Li G, Du X, Xu C, Xu M, Liu R, Deng X, Zheng Z. Integrated bacterial transcriptome and host metabolome analysis reveals insights into " Candidatus Liberibacter asiaticus" population dynamics in the fruit pith of three citrus cultivars with different tolerance. Microbiol Spectr 2024; 12:e0405223. [PMID: 38440971 PMCID: PMC10986616 DOI: 10.1128/spectrum.04052-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/22/2024] [Indexed: 03/06/2024] Open
Abstract
"Candidatus Liberibacter asiaticus" (CLas), the causal agent of citrus Huanglongbing (HLB), is able to multiply to a high abundance in citrus fruit pith. However, little is known about the biological processes and phytochemical substances that are vital for CLas colonization and growth in fruit pith. In this study, CLas-infected fruit pith of three citrus cultivars ("Shatangju" mandarin, "Guanxi" pomelo, and "Shatian" pomelo) exhibiting different tolerance to CLas were collected and used for dual RNA-Seq and untargeted metabolome analysis. Comparative transcriptome analysis found that the activation of the CLas noncyclic TCA pathway and pathogenic-related effectors could contribute to the colonization and growth of CLas in fruit pith. The pre-established Type 2 prophage in the CLas genome and the induction of its CRISPR/cas system could enhance the phage resistance of CLas and, in turn, facilitate CLas population growth in fruit pith. CLas infection caused the accumulation of amino acids that were correlated with tolerance to CLas. The accumulation of most sugars and organic acids in CLas-infected fruit pith, which could be due to the phloem blockage caused by CLas infection, was thought to be beneficial for CLas growth in localized phloem tissue. The higher levels of flavonoids and terpenoids in the fruit pith of CLas-tolerant cultivars, particularly those known for their antimicrobial properties, could hinder the growth of CLas. This study advances our understanding of CLas multiplication in fruit pith and offers novel insight into metabolites that could be responsible for tolerance to CLas or essential to CLas population growth.IMPORTANCECitrus Huanglongbing (HLB, also called citrus greening disease) is a highly destructive disease currently threatening citrus production worldwide. HLB is caused by an unculturable bacterial pathogen, "Candidatus Liberibacter asiaticus" (CLas). However, the mechanism of CLas colonization and growth in citrus hosts is poorly understood. In this study, we utilized the fruit pith tissue, which was able to maintain the CLas at a high abundance, as the materials for dual RNA-Seq and untargeted metabolome analysis, aiming to reveal the biological processes and phytochemical substances that are vital for CLas colonization and growth. We provided a genome-wide CLas transcriptome landscape in the fruit pith of three citrus cultivars with different tolerance and identified the important genes/pathways that contribute to CLas colonization and growth in the fruit pith. Metabolome profiling identified the key metabolites, which were mainly affected by CLas infection and influenced the population dynamic of CLas in fruit pith.
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Affiliation(s)
- Yun Li
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Ruifeng Ma
- Institute of Fruit Tree Research, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou, Guangdong, China
| | - Chenying Gao
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Ziyi Li
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Yongqin Zheng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Fang Fang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Cheng Wang
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Guohua Li
- Institute of Fruit Tree Research, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou, Guangdong, China
| | - Xiaozhen Du
- Institute of Fruit Tree Research, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou, Guangdong, China
| | - Changbao Xu
- College of Horticulture, South China Agricultural University, Guangzhou, Guangdong, China
| | - Meirong Xu
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Rui Liu
- Institute of Fruit Tree Research, Meizhou Academy of Agriculture and Forestry Sciences, Meizhou, Guangdong, China
| | - Xiaoling Deng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
| | - Zheng Zheng
- National Key Laboratory of Green Pesticide, South China Agricultural University, Guangzhou, Guangdong, China
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou, China
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Xia K, Feng Z, Zhang X, Zhou Y, Zhu H, Yao Q. Potential functions of the shared bacterial taxa in the citrus leaf midribs determine the symptoms of Huanglongbing. FRONTIERS IN PLANT SCIENCE 2023; 14:1270929. [PMID: 38034569 PMCID: PMC10682189 DOI: 10.3389/fpls.2023.1270929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023]
Abstract
Instruction Citrus is a globally important fruit tree whose microbiome plays a vital role in its growth, adaptability, and resistance to stress. Methods With the high throughput sequencing of 16S rRNA genes, this study focused on analyzing the bacterial community, especially in the leaf midribs, of healthy and Huanglongbing (HLB)-infected plants. Results We firstly identified the shared bacterial taxa in the midribs of both healthy and HLB-infected plants, and then analyzed their functions. Results showed that the shared bacterial taxa in midribs belonged to 62 genera, with approximately 1/3 of which modified in the infected samples. Furthermore, 366 metabolic pathways, 5851 proteins, and 1833 enzymes in the shared taxa were predicted. Among these, three metabolic pathways and one protein showed significant importance in HLB infection. With the random forest method, six genera were identified to be significantly important for HLB infection. Notably, four of these genera were also among the significantly different shared taxa. Further functional characterization of these four genera revealed that Pseudomonas and Erwinia likely contributed to plant defense against HLB, while Streptomyces might have implications for plant defense against HLB or the pathogenicity of Candidatus Liberibacter asiaticus (CLas). Disccusion Overall, our study highlights that the functions of the shared taxa in leaf midribs are distinguished between healthy and HLB-infected plants, and these microbiome-based findings can contribute to the management and protection of citrus crops against CLas.
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Affiliation(s)
- Kaili Xia
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Zengwei Feng
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Xianjiao Zhang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yang Zhou
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Honghui Zhu
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Qing Yao
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Horticulture, South China Agricultural University, Guangzhou, China
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Xu J, Dai S, Wang X, Gentile A, Zhang Z, Xie Q, Su Y, Li D, Wang B. Actin-Depolymerizing Factor Gene Family Analysis Revealed That CsADF4 Increased the Sensitivity of Sweet Orange to Bacterial Pathogens. PLANTS (BASEL, SWITZERLAND) 2023; 12:3054. [PMID: 37687300 PMCID: PMC10490069 DOI: 10.3390/plants12173054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 08/14/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023]
Abstract
The actin-depolymerizing factor (ADF) gene family regulates changes in actin. However, the entire ADF family in the sweet orange Citrus sinensis has not been systematically identified, and their expressions in different organs and biotic stress have not been determined. In this study, through phylogenetic analysis of the sweet orange ADF gene family, seven CsADFs were found to be highly conserved and sparsely distributed across the four chromosomes. Analysis of the cis-regulatory elements in the promoter region showed that the CsADF gene had the potential to impact the development of sweet oranges under biotic or abiotic stress. Quantitative fluorescence analysis was then performed. Seven CsADFs were differentially expressed against the invasion of Xcc and CLas pathogens. It is worth noting that the expression of CsADF4 was significantly up-regulated at 4 days post-infection. Subcellular localization results showed that CsADF4 was localized in both the nucleus and the cytoplasm. Overexpression of CsADF4 enhanced the sensitivity of sweet orange leaves to Xcc. These results suggest that CsADFs may regulate the interaction of C. sinensis and bacterial pathogens, providing a way to further explore the function and mechanisms of ADF in the sweet orange.
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Affiliation(s)
- Jing Xu
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China (X.W.)
- National Citrus Improvement Center, Hunan Agricultural University, Changsha 410128, China
| | - Suming Dai
- National Citrus Improvement Center, Hunan Agricultural University, Changsha 410128, China
- College of Horticulture, Hunan Agricultural University, Changsha 410128, China
| | - Xue Wang
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China (X.W.)
- National Citrus Improvement Center, Hunan Agricultural University, Changsha 410128, China
| | - Alessandra Gentile
- National Citrus Improvement Center, Hunan Agricultural University, Changsha 410128, China
- Department of Agriculture and Food Science, University of Catania, 95123 Catania, Italy
| | - Zhuo Zhang
- Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha 410128, China
| | - Qingxiang Xie
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China (X.W.)
| | - Yajun Su
- National Citrus Improvement Center, Hunan Agricultural University, Changsha 410128, China
- College of Horticulture, Hunan Agricultural University, Changsha 410128, China
| | - Dazhi Li
- National Citrus Improvement Center, Hunan Agricultural University, Changsha 410128, China
- College of Horticulture, Hunan Agricultural University, Changsha 410128, China
| | - Bing Wang
- College of Plant Protection, Hunan Agricultural University, Changsha 410128, China (X.W.)
- National Citrus Improvement Center, Hunan Agricultural University, Changsha 410128, China
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Zhang S, Wang X, He J, Zhang S, Zhao T, Fu S, Zhou C. A Sec-dependent effector, CLIBASIA_04425, contributes to virulence in ' Candidatus Liberibater asiaticus'. FRONTIERS IN PLANT SCIENCE 2023; 14:1224736. [PMID: 37554557 PMCID: PMC10405523 DOI: 10.3389/fpls.2023.1224736] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/05/2023] [Indexed: 08/10/2023]
Abstract
Citrus Huanglongbing (HLB) is the most destructive citrus disease worldwide, mainly caused by 'Candidatus Liberibacter asiaticus' (CLas). It encodes a large number of Sec-dependent effectors that contribute to HLB progression. In this study, an elicitor triggering ROS burst and cell death in Nicotiana benthamiana, CLIBASIA_04425 (CLas4425), was identified. Of particular interest, its cell death-inducing activity is associated with its subcellular localization and the cytoplasmic receptor Botrytis-induced kinase 1 (BIK1). Compared with CLas infected psyllids, CLas4425 showed higher expression level in planta. The transient expression of CLas4425 in N. benthamiana and its overexpression in Citrus sinensis enhanced plant susceptibility to Pseudomonas syringae pv. tomato DC3000 ΔhopQ1-1 and CLas, respectively. Furthermore, the salicylic acid (SA) level along with the expression of genes NPR1/EDS1/NDR1/PRs in SA signal transduction was repressed in CLas4425 transgenic citrus plants. Taken together, CLas4425 is a virulence factor that promotes CLas proliferation, likely by interfering with SA-mediated plant immunity. The results obtained facilitate our understanding of CLas pathogenesis.
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Affiliation(s)
- Shushe Zhang
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Chinese Academy of Agriculture Sciences, Institute of Plant Protection, Beijing, China
| | - Xuefeng Wang
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
| | - Jun He
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
| | - Song Zhang
- Guangxi Citrus Breeding and Cultivation Engineering Technology Center Academy of Specialty Crops, Guangxi, Guilin, China
| | - Tingchang Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Chinese Academy of Agriculture Sciences, Institute of Plant Protection, Beijing, China
| | - Shimin Fu
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
| | - Changyong Zhou
- Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, China
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Zhang M, Wang F, Hu Z, Wang X, Yi Q, Feng J, Zhao X, Zhu S. CcRR5 interacts with CcRR14 and CcSnRK2s to regulate the root development in citrus. FRONTIERS IN PLANT SCIENCE 2023; 14:1170825. [PMID: 37139114 PMCID: PMC10150009 DOI: 10.3389/fpls.2023.1170825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 03/27/2023] [Indexed: 05/05/2023]
Abstract
Response regulator (RR) is an important component of the cytokinin (CK) signal transduction system associated with root development and stress resistance in model plants. However, the function of RR gene and the molecular mechanism on regulating the root development in woody plants such as citrus remain unclear. Here, we demonstrate that CcRR5, a member of the type A RR, regulates the morphogenesis of root through interacting with CcRR14 and CcSnRK2s in citrus. CcRR5 is mainly expressed in root tips and young leaves. The activity of CcRR5 promoter triggered by CcRR14 was proved with transient expression assay. Seven SnRK2 family members with highly conserved domains were identified in citrus. Among them, CcSnRK2.3, CcSnRK2.6, CcSnRK2.7, and CcSnRK2.8 can interact with CcRR5 and CcRR14. Phenotypic analysis of CcRR5 overexpressed transgenic citrus plants indicated that the transcription level of CcRR5 was associated with root length and lateral root numbers. This was also correlated to the expression of root-related genes and thus confirmed that CcRR5 is involved in the root development. Taken together, the results of this study indicate that CcRR5 is a positive regulator of root growth and CcRR14 directly regulates the expression of CcRR5. Both CcRR5 and CcRR14 can interact with CcSnRK2s.
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Affiliation(s)
- Manman Zhang
- Citrus Research Institute, Southwest University, Chongqing, China
- National Citrus Engineering Research Center, Southwest University, Chongqing, China
| | - Fusheng Wang
- Citrus Research Institute, Southwest University, Chongqing, China
- National Citrus Engineering Research Center, Southwest University, Chongqing, China
| | - Zhou Hu
- Citrus Research Institute, Southwest University, Chongqing, China
- National Citrus Engineering Research Center, Southwest University, Chongqing, China
| | - Xiaoli Wang
- Citrus Research Institute, Southwest University, Chongqing, China
- National Citrus Engineering Research Center, Southwest University, Chongqing, China
| | - Qian Yi
- Citrus Research Institute, Southwest University, Chongqing, China
- National Citrus Engineering Research Center, Southwest University, Chongqing, China
| | - Jipeng Feng
- Citrus Research Institute, Southwest University, Chongqing, China
- National Citrus Engineering Research Center, Southwest University, Chongqing, China
| | - Xiaochun Zhao
- Citrus Research Institute, Southwest University, Chongqing, China
- National Citrus Engineering Research Center, Southwest University, Chongqing, China
- *Correspondence: Xiaochun Zhao, ; Shiping Zhu,
| | - Shiping Zhu
- Citrus Research Institute, Southwest University, Chongqing, China
- National Citrus Engineering Research Center, Southwest University, Chongqing, China
- *Correspondence: Xiaochun Zhao, ; Shiping Zhu,
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