Phytoalexin formation in fire blight-infected apple

Chizzali, Cornelia; Gaid, Mariam; Belkheir, Asma K.; Beuerle, Till; Hänsch, Robert; Richter, Klaus; Flachowsky, Henryk; Peil, Andreas; Hanke, Magda‐Viola; Liu, Benye

doi:10.1007/s00468-012-0808-2

Cited by 18 publications

(5 citation statements)

References 34 publications

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“…In the literature, phytoalexins are described to be a part of the induced defense response against biotic stressors, fungi in particular [59]. BIS3 expression was reported previously in apple upon fire blight infection [60] and upon infection with Pythium ultimum, one causal agent of ARD [61,62]. Taking these studies together with further studies from our group [11,32,33,63], the phytoalexin biosynthesis is a clear and highly specific part of the Malus response to ARD.…”

Section: Plos Onementioning

confidence: 56%

Identification and validation of early genetic biomarkers for apple replant disease

et al. 2020

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Apple replant disease (ARD) is a serious threat to producers of apple trees and fruits worldwide. The ARD etiology is not unraveled and managing options are either economically not applicable or environmentally harmful. Thus, interest is given in biomarkers that allow to indicate ARD situations at early time points in order to classify soils according to ARD severity but also to analyze the effectiveness to potential countermeasures. This study aimed at (i) identifying ARD biomarkers on the transcriptional level in root tissue by analyzing the expression of previously identified candidate genes in ARD soils of different origin and texture and (ii) testing the specificity of these marker genes to ARD. In vitro propagated M26 plantlets were submitted to a bio-test with three ARD soils, either untreated or disinfected by γ-irradiation. Expression of seven candidate genes identified in a previous transcriptomic study was investigated by RT-qPCR in a time course experiment. Already three days after planting, a prominent upregulation of the phytoalexin biosynthesis genes biphenyl synthase 3 (BIS3) and biphenyl 4-hydroxylase (B4Hb) was observed in the untreated ARD variants of all three soils. The phytoalexin composition in roots was comparable for all three soils and the total phytoalexin content correlated with the expression of BIS3 and B4Hb. The third promising candidate gene that was upregulated under ARD conditions was the ethyleneresponsive transcription factor 1B-like (ERF1B). In a second experiment M26 plantlets were exposed to different abiotic stressors, namely heat, salt and nutrient starvation, and candidate gene expression was determined in the roots. The expression levels of BIS3 and B4Hb were highly and specifically upregulated in ARD soil, but not upon the abiotic stress conditions, whereas ERF1B also showed higher expression under heat stress. In conclusion, BIS3 and B4Hb are recommended as early ARD biomarkers due to their high expression levels and their high specificity.

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Section: Plos Onementioning

confidence: 56%

Identification and validation of early genetic biomarkers for apple replant disease

et al. 2020

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“…In particular, genes of the biphenyl biosynthetic pathway were rapidly activated in the roots of apple plants grown in ARD soil (Zhu et al, 2014;Zhu et al, 2016;Weiß et al, 2017a;Weiß et al, 2017b). Phytoalexins like biphenyls and dibenzofurans are known to act in an induced defense mechanism against biotic stressors, such as fungi and bacteria (Ahuja et al, 2012;Chizzali et al, 2012b;Chizzali and Beerhues, 2012;Chizzali et al, 2013). Interestingly, the activation of phytoalexin biosynthesis genes was also found when the plants were inoculated with Pythium ultimum, one component of the ARD complex (Shin et al, 2016b;Zhu et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Genes Involved in Stress Response and Especially in Phytoalexin Biosynthesis Are Upregulated in Four Malus Genotypes in Response to Apple Replant Disease

et al. 2020

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Apple replant disease (ARD) is a soil-borne disease, which is of particular importance for fruit tree nurseries and fruit growers. The disease manifests by a poor vegetative development, stunted growth, and reduced yield in terms of quantity and quality, if apple plants (usually rootstocks) are replanted several times at the same site. Genotypespecific differences in the reaction of apple plants to ARD are documented, but less is known about the genetic mechanisms behind this symptomatology. Recent transcriptome analyses resulted in a number of candidate genes possibly involved in the plant response. In the present study, the expression of 108 selected candidate genes was investigated in root and leaf tissue of four different apple genotypes grown in untreated ARD soil and ARD soil disinfected by g-irradiation originating from two different sites in Germany. Thirty-nine out of the 108 candidate genes were differentially expressed in roots by taking a p-value of < 0.05 and a fold change of > 1.5 as cutoff. Sixteen genes were more than 4.5-fold upregulated in roots of plants grown in ARD soil. The four genes MNL2 (putative mannosidase); ALF5 (multi antimicrobial extrusion protein); UGT73B4 (uridine diphosphate (UDP)-glycosyltransferase 73B4), and ECHI (chitinbinding) were significantly upregulated in roots. These genes seem to be related to the host plant response to ARD, although they have never been described in this context before. Six of the highly upregulated genes belong to the phytoalexin biosynthesis pathway. Their genotype-specific gene expression pattern was consistent with the phytoalexin content measured in roots. The biphenyl synthase (BIS) genes were found to be useful as early biomarkers for ARD, because their expression pattern correlated well with the phenotypic reaction of the Malus genotypes investigated.

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“…This observation made with transiently transformed N. benthamiana epidermis cells using the 35S promoter differs from immunolocalization of MdBIS in fire blight infected shoots of apple. Biphenyl and dibenzofuran phytoalexins do not occur in apple leaves infected with E. amylovora and V. inaequalis but accumulate in the transition zone of stems, which is located between the necrotic and healthy stem segments (Hrazdina and Borejsza‐Wysocki, ; Chizzali et al ., ,b, ). The MdBIS isoenzyme that is involved in the biosynthesis of phytoalexins in diseased apple shoots is MdBIS3.…”

Section: Discussionmentioning

confidence: 99%

“…Accumulation of the compounds is a part of the defence arsenal against destructive diseases, such as scab, fire blight, and powdery mildew (Gessler and Patocchi, ). Year by year, these infections cause massive losses of fruits (pomes in the Malinae) and trees (Chizzali et al ., ). Application of pesticides is strictly regulated and the development of pathogen insensitivities is continuously increasing (Hollomon and Brent, ; Vogt et al ., ).…”

Section: Introductionmentioning

confidence: 97%

O‐Methyltransferases involved in biphenyl and dibenzofuran biosynthesis

et al. 2015

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SUMMARYBiphenyls and dibenzofurans are the phytoalexins of the Malinae involving apple and pear. Biosynthesis of the defence compounds includes two O-methylation reactions. cDNAs encoding the O-methyltransferase (OMT) enzymes were isolated from rowan (Sorbus aucuparia) cell cultures after treatment with an elicitor preparation from the scab-causing fungus, Venturia inaequalis. The preferred substrate for SaOMT1 was 3,5-dihydroxybiphenyl, supplied by the first pathway-specific enzyme, biphenyl synthase (BIS). 3,5-Dihydroxybiphenyl underwent a single methylation reaction in the presence of S-adenosyl-L-methionine (SAM). The second enzyme, SaOMT2, exhibited its highest affinity for noraucuparin, however the turnover rate was greater with 5-hydroxyferulic acid. Both substrates were only methylated at the meta-positioned hydroxyl group. The substrate specificities of the OMTs and the regiospecificities of their reactions were rationalized by homology modeling and substrate docking. Interaction of the substrates with SAM also took place at a position other than the sulfur group. Expression of SaOMT1, SaOMT2 and SaBIS3 was transiently induced in rowan cell cultures by the addition of the fungal elicitor. While the immediate SaOMT1 products were not detectable in elicitor-treated cell cultures, noraucuparin and noreriobofuran accumulated transiently, followed by increasing levels of the SaOMT2 products aucuparin and eriobofuran. SaOMT1, SaOMT2 and SaBIS3 were N-and C-terminally fused with the super cyan fluorescent protein and a modified yellow fluorescent protein, respectively. All the fluorescent reporter fusions were localized to the cytoplasm of Nicotiana benthamiana leaf epidermis cells. A revised biosynthetic pathway of biphenyls and dibenzofurans in the Malinae is presented.

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Phytoalexin formation in fire blight-infected apple

Cited by 18 publications

References 34 publications

Identification and validation of early genetic biomarkers for apple replant disease

Identification and validation of early genetic biomarkers for apple replant disease

Genes Involved in Stress Response and Especially in Phytoalexin Biosynthesis Are Upregulated in Four Malus Genotypes in Response to Apple Replant Disease

O‐Methyltransferases involved in biphenyl and dibenzofuran biosynthesis

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