Lower Concentrations of Microelements in Leaves of Citrus Infected with 'Candidatus Liberibacter asiaticus'

Masaoka, Yoshikuni; Pustika, Aryna; Subandiyah, Siti; Okada, Akiko; Hanundin, Eko; Purwanto, Benito Heru; Okuda, Mitsuru; Okada, Yoshihiro; Saito, Akira; Holford, Paul; Beattie, Andrew; Iwanami, Toru

doi:10.6090/jarq.45.269

Cited by 35 publications

(41 citation statements)

References 14 publications

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“…The highest Ct value of Las was in the nutrition only treatment with the greatest leaf Mn, Zn and B in May 2012, indicating that leaf Mn (r=0.604, n=16, p<0.05), Zn (r=0.612, n=16, p<0.05) and B (r=0.609, n=16, p<0.05) were negatively correlated with the Las titre. Lower Fe and Zn were observed in symptomatic HLB infected leaf samples than in healthy leaf samples(Masaoka et al 2011). These results are consistent with the RDA results that leaf Ca, Mn, Zn and B were positively correlated with the Ct values of Las, suggesting that 'Boyd nutrient solution' application could improve the citrus nutrition status and thus lower the Las titres.…”

supporting

confidence: 94%

“…In particular, micronutrients combined with salicylic acid and/or phosphite have been applied, often as foliar sprays, to maintain the productive capacity of HLB infected trees (Ahmad et al 2011;Masaoka et al 2011;Razi et al 2011). The effectiveness of these treatments has been controversial (Gottwald et al 2012), but balanced nutrition likely slows down tree decline due to HLB, considering the occurrence of healthy looking trees many years after Las infection was demonstrated (field observations by the authors).…”

Section: Introductionmentioning

confidence: 99%

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Relation between plant nutrition, hormones, insecticide applications, bacterial endophytes, and Candidatus Liberibacter Ct values in citrus trees infected with Huanglongbing

et al. 2013

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Intensive insecticide and nutrient management have been attempted worldwide to reduce citrus huanglongbing (HLB) symptom development and yield loss. However, effects of insecticide and nutrient applications on HLB have been poorly understood. Leaf nutrients, jasmonic and salicylic acid contents, cycle threshold (Ct) values of Ca. Liberibacter asiaticus (Las), and community structure of endophytic α-proteobacteria were evaluated after insecticide treatment, 'nutrition' treatment (including systemic resistance inducing agents), or both in comparison with a control in a two-factor field experiment in 2008-2012. Leaf N, Mn, Zn and B significantly increased whilst Cu decreased after nutrient applications. Salicylic acid significantly increased in old leaves treated with insecticides, nutrients or both, and in young leaves treated with nutrients only. The jasmonic acid concentration was highest after the nutrition treatment in both old and young leaves. Ct values of Las and leaf area and weight significantly increased after long-term nutrient applications in 2011 and/or 2012. Redundancy analysis of the endophytic α-proteobacteria community structure indicated that the communities were mainly separated according to nutrient applications, which were positively associated with Ct values of Las and Ca, Mn, Zn, B, Mg, and Fe contents in leaf samples collected in 2012. Thus, effects of insecticides on HLB were significant in the early 2-year period whilst nutrients had significant effects on Las content and leaf size and weight after at least 3 years of application.

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supporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Relation between plant nutrition, hormones, insecticide applications, bacterial endophytes, and Candidatus Liberibacter Ct values in citrus trees infected with Huanglongbing

et al. 2013

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“…The overexpression of transcripts for Zn transporters in citrus in the late stages of infection with CaLam or CaLas are expected, because the symptoms in the leaves of susceptible citrus plants often resemble those of zinc deficiency. In fact, in some citrus genotypes, the concentrations of Zn and Fe in infected plants was found to be approximately half those in healthy plants, which indicates that zinc homoeostasis is significantly affected during infection [24]. As an important micronutrient in plants, zinc has structural (e.g., carbonic anhydrase) and catalytic functions (e.g., superoxide dismutase CuZn-SOD) in many of enzymes.…”

Section: Discussionmentioning

confidence: 99%

“…In susceptible citrus infected with Liberibacters, zinc deficiency has, to some extent, been associated with inefficient translocation of this mineral by the roots. An important issue to be addressed is whether Liberibacters could directly or indirectly reduce the availability of this metal as a strategy to favor the infection process [24], as observed for Xanthomonas oryzae in rice [27]. …”

Section: Discussionmentioning

confidence: 99%

CandidatusLiberibacter americanus induces significant reprogramming of the transcriptome of the susceptible citrus genotype

et al. 2013

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BackgroundCitrus huanglongbing (HLB) disease is caused by endogenous, phloem-restricted, Gram negative, uncultured bacteria named Candidatus Liberibacter africanus (CaLaf), Ca. L. asiaticus (CaLas), and Ca. L. americanus (CaLam), depending on the continent where the bacteria were first detected. The Asian citrus psyllid vector, Diaphorina citri, transmits CaLas and CaLam and both Liberibacter species are present in Brazil. Several studies of the transcriptional response of citrus plants manifesting HLB symptoms have been reported, but only for CaLas infection. This study evaluated the transcriptional reprogramming of a susceptible genotype of sweet orange challenged with CaLam, using a customized 385K microarray containing approximately 32,000 unigene transcripts. We analyzed global changes in gene expression of CaLam-infected leaves of sweet orange during the symptomatic stage of infection and compared the results with previously published microarray studies that used CaLas-infected plants. Twenty candidate genes were selected to validate the expression profiles in symptomatic and asymptomatic PCR-positive leaves infected with CaLas or CaLam.ResultsThe microarray analysis identified 633 differentially expressed genes during the symptomatic stage of CaLam infection. Among them, 418 (66%) were upregulated and 215 (34%) were down regulated. Five hundred and fourteen genes (81%) were orthologs of genes from Arabidopsis thaliana. Gene set enrichment analysis (GSEA) revealed that several of the transcripts encoded transporters associated with the endomembrane system, especially zinc transport. Among the most biologically relevant gene transcripts in GSEA were those related to signaling, metabolism and/or stimulus to hormones, genes responding to stress and pathogenesis, biosynthesis of secondary metabolites, oxidative stress and transcription factors belonging to different families. Real time PCR of 20 candidate genes validated the expression pattern of some genes in symptomatic and asymptomatic leaves infected with CaLam or CaLas.ConclusionsMany gene transcripts and biological processes are significantly altered upon CaLam infection. Some of them had been identified in response to CaLas infection, while others had not been previously reported. These data will be useful for selecting target genes for genetic engineering to control HLB.

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“…Furthermore, symptoms of HLB are very similar to those of Zn-deficiency and citrus plants have generally shown reduced concentrations of Zn in tissues due to Las infection [3,24,51]. It was therefore surprising to see a 128% increase in Zn concentrations in lemon leaves in response to Las infection (Figure 5), especially when further investigations of the nutritional content of other citrus and citrus-related plants showed a reduction in leaf-Zn concentrations (unpublished data).…”

Section: Discussionmentioning

confidence: 99%

Study on Citrus Response to Huanglongbing Highlights a Down-Regulation of Defense-Related Proteins in Lemon Plants Upon ‘Ca. Liberibacter asiaticus’ Infection

2013

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Citrus huanglongbing (HLB) is a highly destructive disease of citrus presumably caused by ‘ Candidatus Liberibacter asiaticus ’ (Las), a gram-negative, insect-transmitted, phloem-limited α-proteobacterium. Although almost all citrus plants are susceptible to HLB, reports have shown reduced susceptibility to Las infection in lemon ( Citrus limon ) plants. The aim of this study is to identify intra-species specific molecular mechanisms associated with Las-induced responses in lemon plants. To achieve this, comparative 2-DE and mass spectrometry, in addition to Inductively Coupled Plasma Spectroscopy (ICPS) analyses, were applied to investigate differences in protein accumulation and the concentrations of cationic elements in leaves of healthy and Las-infected lemon plants. Results showed a differential accumulation of 27 proteins, including an increase in accumulation of starch synthase but decrease in the production of photosynthesis-related proteins in Las-infected lemon plants compared to healthy plants. Furthermore, there was a 6% increase (P > 0.05) in K concentration in leaves of lemon plants upon Las infection, which support results from previous studies and might represent a common response pattern of citrus plants to Las infection. Interestingly, contrary to reports from prior studies, this study showed a general reduction in the production of defense-related pathogen-response proteins but a 128% increase in Zn concentration in lemon plants in response to Las infection. Taken together, this study sheds light on general and intra-species specific responses associated with the response of citrus plants to Las.

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Lower Concentrations of Microelements in Leaves of Citrus Infected with 'Candidatus Liberibacter asiaticus'

Cited by 35 publications

References 14 publications

Relation between plant nutrition, hormones, insecticide applications, bacterial endophytes, and Candidatus Liberibacter Ct values in citrus trees infected with Huanglongbing

Relation between plant nutrition, hormones, insecticide applications, bacterial endophytes, and Candidatus Liberibacter Ct values in citrus trees infected with Huanglongbing

CandidatusLiberibacter americanus induces significant reprogramming of the transcriptome of the susceptible citrus genotype

Study on Citrus Response to Huanglongbing Highlights a Down-Regulation of Defense-Related Proteins in Lemon Plants Upon ‘Ca. Liberibacter asiaticus’ Infection

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