Cryphonectria cubensis on an indigenous host in Brazil: a possible origin for eucalyptus canker disease?

Abstract Background Valsa canker is a serious disease in the stem of Malus sieversii, caused by Valsa mali. However, little is known about the global response mechanism in M. sieversii to V. mali infection. Results Phytohormone jasmonic acid (JA) and salicylic acid (SA) profiles and transcriptome analysis were used to elaborate on the dynamic response mechanism. We determined that the JA was initially produced to respond to the necrotrophic pathogen V. mali infection at the early response stage, then get synergistically transduced with SA to respond at the late response stage. Furthermore, we adopted Pacific Biosciences (PacBio) full-length sequencing to identify differentially expressed transcripts (DETs) during the canker response stage. We obtained 52,538 full-length transcripts, of which 8139 were DETs. Total 1336 lncRNAs, 23,737 alternative polyadenylation (APA) sites and 3780 putative transcription factors (TFs) were identified. Additionally, functional annotation analysis of DETs indicated that the wild apple response to the infection of V. mali involves plant-pathogen interaction, plant hormone signal transduction, flavonoid biosynthesis, and phenylpropanoid biosynthesis. The co-expression network of the differentially expressed TFs revealed 264 candidate TF transcripts. Among these candidates, the WRKY family was the most abundant. The MsWRKY7 and MsWRKY33 were highly correlated at the early response stage, and MsWRKY6, MsWRKY7, MsWRKY19, MsWRKY33, MsWRKY40, MsWRKY45, MsWRKY51, MsWRKY61, MsWRKY75 were highly correlated at the late stage. Conclusions The full-length transcriptomic analysis revealed a series of immune responsive events in M. sieversii in response to V. mali infection. The phytohormone signal pathway regulatory played an important role in the response stage. Additionally, the enriched disease resistance pathways and differentially expressed TFs dynamics collectively contributed to the immune response. This study provides valuable insights into a dynamic response in M. sieversii upon the necrotrophic pathogen V. mali infection, facilitates understanding of response mechanisms to canker disease for apple, and provides supports in the identification of potential resistance genes in M. sieversii.

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Modified Monosaccharides Content of Xanthan Gum Impairs Citrus Canker Disease by Affecting the Epiphytic Lifestyle of Xanthomonas citri subsp. citri

Microorganisms ◽

10.3390/microorganisms9061176 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1176

Author(s):

Simone Cristina Picchi ◽

Laís Moreira Granato ◽

Maria Júlia Festa Franzini ◽

Maxuel Oliveira Andrade ◽

Marco Aurélio Takita ◽

...

Keyword(s):

Biofilm Formation ◽

Xanthan Gum ◽

Wild Type Strain ◽

Natural Infection ◽

Citrus Canker ◽

Wild Type ◽

Xanthomonas Citri ◽

Canker Disease ◽

Key Enzyme ◽

Citrus Canker Disease

Xanthomonas citri subsp. citri (X. citri) is a plant pathogenic bacterium causing citrus canker disease. The xanA gene encodes a phosphoglucomutase/phosphomannomutase protein that is a key enzyme required for the synthesis of lipopolysaccharides and exopolysaccharides in Xanthomonads. In this work, firstly we isolated a xanA transposon mutant (xanA::Tn5) and analyzed its phenotypes as biofilm formation, xanthan gum production, and pathogenesis on the sweet orange host. Moreover, to confirm the xanA role in the impaired phenotypes we further produced a non-polar deletion mutant (ΔxanA) and performed the complementation of both xanA mutants. In addition, we analyzed the percentages of the xanthan gum monosaccharides produced by X. citri wild-type and xanA mutant. The mutant strain had higher ratios of mannose, galactose, and xylose and lower ratios of rhamnose, glucuronic acid, and glucose than the wild-type strain. Such changes in the saccharide composition led to the reduction of xanthan yield in the xanA deficient strain, affecting also other important features in X. citri, such as biofilm formation and sliding motility. Moreover, we showed that xanA::Tn5 caused no symptoms on host leaves after spraying, a method that mimetics the natural infection condition. These results suggest that xanA plays an important role in the epiphytical stage on the leaves that is essential for the successful interaction with the host, including adaptive advantage for bacterial X. citri survival and host invasion, which culminates in pathogenicity.

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Enzymatic activities of citrus leaves from plants re resistant and susceptible to citrus bacterial canker disease

Environmental and Experimental Botany ◽

10.1016/0098-8472(92)90059-b ◽

1992 ◽

Vol 32 (4) ◽

pp. 465-470 ◽

Cited By ~ 7

Author(s):

H.J. Jiao ◽

S.Y. Wang ◽

E.L. Civerolo

Keyword(s):

Enzymatic Activities ◽

Bacterial Canker ◽

Canker Disease ◽

Citrus Bacterial Canker ◽

Citrus Leaves

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Multigene phylogeny and morphology reveal Phaeobotryon rhois sp. nov. (Botryosphaeriales, Ascomycota)

Phytotaxa ◽

10.11646/phytotaxa.205.2.2 ◽

2015 ◽

Vol 205 (2) ◽

pp. 90 ◽

Cited By ~ 4

Author(s):

XIN-LEI FAN ◽

KEVIN D. HYDE ◽

JIAN-KUI LIU ◽

YING-MEI LIANG ◽

CHENG-MING TIAN

Keyword(s):

New Species ◽

Distinct Species ◽

Similar Species ◽

Multigene Phylogeny ◽

Fruiting Bodies ◽

Canker Disease ◽

Multigene Analysis ◽

The Family ◽

Rhus Typhina ◽

A New Species

The family Botryosphaeriaceae encompasses important plant-associated pathogens, endophytes and saprobes with a wide geographical and host distribution. Two dark-spored botryosphaeriaceous taxa associated with Rhus typhina dieback and canker disease were collected from Ningxia Province, in northwestern China. Morphology and multigene analysis (ITS, LSU and EF-1α) clearly distinguished this clade as a distinct species in the genus. Phaeobotryon rhois is introduced and illustrated as a new species in this paper. The species is characterized by its globose, unilocular fruiting bodies and small, brown, 1-septate conidia. It can be distinguished from the similar species P. cercidis, P. cupressi, P. mamane and P. quercicola based on host association and conidial size and colour.

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GC-TOF/MS-based metabolomics analysis to investigate the changes driven by N-Acetylcysteine in the plant-pathogen Xanthomonas citri subsp. citri

Scientific Reports ◽

10.1038/s41598-021-95113-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Simone Cristina Picchi ◽

Mariana de Souza e Silva ◽

Luiz Leonardo Saldanha ◽

Henrique Ferreira ◽

Marco Aurélio Takita ◽

...

Keyword(s):

Amino Acids ◽

Cell Proliferation ◽

Plant Pathogen ◽

Model Organism ◽

Citrus Canker ◽

Bacterial Cells ◽

Xanthomonas Citri ◽

Canker Disease ◽

Potential Use

AbstractN-Acetylcysteine (NAC) is an antioxidant, anti-adhesive, and antimicrobial compound. Even though there is much information regarding the role of NAC as an antioxidant and anti-adhesive agent, little is known about its antimicrobial activity. In order to assess its mode of action in bacterial cells, we investigated the metabolic responses triggered by NAC at neutral pH. As a model organism, we chose the Gram-negative plant pathogen Xanthomonas citri subsp. citri (X. citri), the causal agent of citrus canker disease, due to the potential use of NAC as a sustainable molecule against phytopathogens dissemination in citrus cultivated areas. In presence of NAC, cell proliferation was affected after 4 h, but damages to the cell membrane were observed only after 24 h. Targeted metabolite profiling analysis using GC–MS/TOF unravelled that NAC seems to be metabolized by the cells affecting cysteine metabolism. Intriguingly, glutamine, a marker for nitrogen status, was not detected among the cells treated with NAC. The absence of glutamine was followed by a decrease in the levels of the majority of the proteinogenic amino acids, suggesting that the reduced availability of amino acids affect protein synthesis and consequently cell proliferation.

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