Characterization of genetic determinants of the resistance to phylloxera, Daktulosphaira vitifoliae, and the dagger nematode Xiphinema index from muscadine background

Abstract Background: Muscadine (Muscadinia rotundifolia) is known as a resistance source to many pests and diseases in grapevine. The genetics of its resistance to two major grapevine pests, the phylloxera D. vitifoliae and the dagger nematode X. index, vector of the Grapevine fanleaf virus (GFLV) was investigated in a backcross progeny between the F1 resistant hybrid material VRH8771 (Muscadinia-Vitis) derived from the muscadine R source ‘NC184-4’ and V. vinifera cv. ‘Cabernet-Sauvignon’ (CS). Results: In this pseudo-testcross, parental maps were constructed using simple-sequence repeats markers and single nucleotide polymorphism markers from a GBS approach. For the VRH8771 map, 2271 SNP and 135 SSR markers were assembled, resulting in 19 linkage groups (LG) and an average distance between markers of 0.98 cM. Phylloxera resistance was assessed by monitoring root nodosity number in an in planta experiment and larval development in a root in vitro assay. Nematode resistance was studied using 10-12 month long tests for the selection of durable resistance and rating criteria based on nematode reproduction factor and gall index. A major QTL for phylloxera larval development, explaining more than 70% of the total variance and co-localizing with a QTL for nodosity number, was identified on LG 7. Additional QTLs were detected on LG 3 and LG 10, depending on the in planta or in vitro experiments, suggesting that various loci may influence or modulate nodosity formation and larval development. Using a Bulk Segregant Analysis approach and a proportion test, markers clustered in three regions on LG 9, LG 10 and LG 18 were shown to be associated to the nematode resistant phenotype. QTL analysis confirmed the results, although a LOD-score below the significant threshold value was obtained for the QTL on LG 18. Conclusions: Based on a high-resolution linkage map and a segregating grapevine backcross progeny, the first QTLs for resistance to Daktulosphaira vitifoliae and to Xiphinema index were identified from a muscadine source. All together these results open the way to the development of marker-assisted selection in grapevine rootstock breeding programs based on muscadine derived resistance to phylloxera and to X. index in order to delay GFLV transmission.

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Characterization of genetic determinants of the resistance to phylloxera, Daktulosphaira vitifoliae, and the dagger nematode Xiphinema index from muscadine background

10.21203/rs.2.15851/v1 ◽

2019 ◽

Author(s):

Bernadette Rubio ◽

Guillaume Lalanne-Tisné ◽

Roger Voisin ◽

Jean-Pascal Tandonnet ◽

Ulysse Portier ◽

...

Keyword(s):

Larval Development ◽

Durable Resistance ◽

Backcross Progeny ◽

Nematode Resistance ◽

In Planta ◽

Vitro Assay ◽

Nematode Reproduction ◽

Pests And Diseases ◽

Index Vector

Abstract Muscadine ( Muscadinia rotundifolia ) is known as a resistance source to many pests and diseases in grapevine. The genetics of its resistance to two major grapevine pests, the phylloxera D. vitifoliae and the dagger nematode X. index , vector of the Grapevine fanleaf virus (GFLV) was investigated in a backcross progeny between the F1 resistant hybrid material VRH8771 ( Muscadinia-Vitis ) and V. vinifera cv. ‘Cabernet-Sauvignon’. Phylloxera resistance was assessed by monitoring root nodosity number in an “ in planta ” experiment and larval development in a root “ in vitro ” assay. Nematode resistance was studied using 10-12 month long tests for the selection of durable resistance and rating criteria based on nematode reproduction factor and gall index. A major QTL for phylloxera larval development, explaining more than 70% of the total variance and co-localizing with a QTL for nodosity number, was identified on LG 7. Additional QTLs were detected on LG 3 and LG 10, depending on the “ in planta ” or “in vitro” experiments, suggesting that various loci may influence or modulate nodosity formation and larval development. Using a Bulk Segregant Analysis approach and a proportion test, markers clustered in three regions on LG 9, LG 10 and LG 18 were shown to be associated to the nematode resistant. All these results open the way to the development of marker-assisted selection in grapevine rootstock breeding programs based on muscadine derived resistance to phylloxera and to X. index in order to delay GFLV transmission.

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Characterization of genetic determinants of the resistance to phylloxera, Daktulosphaira vitifoliae, and the dagger nematode Xiphinema index from muscadine background

10.21203/rs.2.15851/v3 ◽

2020 ◽

Author(s):

Bernadette Rubio ◽

Guillaume Lalanne-Tisné ◽

Roger Voisin ◽

Jean-Pascal Tandonnet ◽

Ulysse Portier ◽

...

Keyword(s):

Larval Development ◽

Durable Resistance ◽

Backcross Progeny ◽

Nematode Resistance ◽

In Planta ◽

Vitro Assay ◽

Nematode Reproduction ◽

Pests And Diseases ◽

Index Vector

Abstract Muscadine ( Muscadinia rotundifolia ) is known as a resistance source to many pests and diseases in grapevine. The genetics of its resistance to two major grapevine pests, the phylloxera D. vitifoliae and the dagger nematode X. index , vector of the Grapevine fanleaf virus (GFLV) was investigated in a backcross progeny between the F1 resistant hybrid material VRH8771 ( Muscadinia-Vitis ) and V. vinifera cv. ‘Cabernet-Sauvignon’. Phylloxera resistance was assessed by monitoring root nodosity number in an “ in planta ” experiment and larval development in a root “ in vitro ” assay. Nematode resistance was studied using 10-12 month long tests for the selection of durable resistance and rating criteria based on nematode reproduction factor and gall index. A major QTL for phylloxera larval development, explaining more than 70% of the total variance and co-localizing with a QTL for nodosity number, was identified on LG 7. Additional QTLs were detected on LG 3 and LG 10, depending on the “ in planta ” or “in vitro” experiments, suggesting that various loci may influence or modulate nodosity formation and larval development. Using a Bulk Segregant Analysis approach and a proportion test, markers clustered in three regions on LG 9, LG 10 and LG 18 were shown to be associated to the nematode resistant. All these results open the way to the development of marker-assisted selection in grapevine rootstock breeding programs based on muscadine derived resistance to phylloxera and to X. index in order to delay GFLV transmission.

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Grapevine Resistance to the Nematode Xiphinema index Is Durable in Muscadine-Derived Plants Obtained from Hardwood Cuttings but Not from In Vitro

Phytopathology ◽

10.1094/phyto-01-20-0008-r ◽

2020 ◽

Vol 110 (9) ◽

pp. 1565-1571

Author(s):

Van Chung Nguyen ◽

Jean-Pascal Tandonnet ◽

Samira Khallouk ◽

Cyril Van Ghelder ◽

Ulysse Portier ◽

...

Keyword(s):

Natural Resistance ◽

Parasitic Nematodes ◽

Promising Alternative ◽

Nematode Reproduction ◽

Xiphinema Index ◽

Plant Nematode ◽

Hardwood Cutting ◽

Muscadinia Rotundifolia ◽

Reproduction Factor

Breeding for varieties carrying natural resistance (R) against plant-parasitic nematodes is a promising alternative to nematicide ban. In perennial crops, the long plant−nematode interaction increases the risk for R breaking and R durability is a real challenge. In grapevine, the nematode Xiphinema index has a high economic impact by transmitting Grapevine fanleaf virus (GFLV) and, to delay GFLV transmission, rootstocks resistant to this vector are being selected, using Muscadinia rotundifolia in particular as an R source. To optimize in fine this strategy, the durability has been studied under controlled conditions in F1 and BC1 muscadine-derived resistant accessions previously obtained from either hardwood-cutting or in vitro propagation. After inoculation with a mix, in equal proportions, of four lines representative of the X. index diversity, multiplication on plants has been monitored 3 to 6 years. The nematode reproduction factor remained lower than 1 in resistant plants obtained from hardwood cuttings while it increased at values far beyond 1 in resistant plants of in vitro origin. Data for nematode numbers per gram of roots mostly paralleled those obtained for the reproduction factor. The effect of the propagation type on resistance over years was also evaluated for the ratio female/juvenile and the frequency of males. Altogether our results illustrate that the muscadine-derived resistance based on hardwood cuttings is durable. By contrast, in resistant and reference accessions obtained from in vitro, our data suggest that the increased nematode multiplication might be mainly due to the modification of root architecture consecutive to this propagation method.

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A peroxisomal β-oxidative pathway contributes to the formation of C6–C1 aromatic volatiles in poplar

Plant Physiology ◽

10.1093/plphys/kiab111 ◽

2021 ◽

Author(s):

Nathalie D Lackus ◽

Axel Schmidt ◽

Jonathan Gershenzon ◽

Tobias G Köllner

Keyword(s):

Cinnamic Acid ◽

Aromatic Compounds ◽

Populus Trichocarpa ◽

Alternative Pathway ◽

Gene Families ◽

Defense Responses ◽

In Planta ◽

Black Cottonwood ◽

Oxidative Pathway

AbstractBenzenoids (C6–C1 aromatic compounds) play important roles in plant defense and are often produced upon herbivory. Black cottonwood (Populus trichocarpa) produces a variety of volatile and nonvolatile benzenoids involved in various defense responses. However, their biosynthesis in poplar is mainly unresolved. We showed feeding of the poplar leaf beetle (Chrysomela populi) on P. trichocarpa leaves led to increased emission of the benzenoid volatiles benzaldehyde, benzylalcohol, and benzyl benzoate. The accumulation of salicinoids, a group of nonvolatile phenolic defense glycosides composed in part of benzenoid units, was hardly affected by beetle herbivory. In planta labeling experiments revealed that volatile and nonvolatile poplar benzenoids are produced from cinnamic acid (C6–C3). The biosynthesis of C6–C1 aromatic compounds from cinnamic acid has been described in petunia (Petunia hybrida) flowers where the pathway includes a peroxisomal-localized chain shortening sequence, involving cinnamate-CoA ligase (CNL), cinnamoyl-CoA hydratase/dehydrogenase (CHD), and 3-ketoacyl-CoA thiolase (KAT). Sequence and phylogenetic analysis enabled the identification of small CNL, CHD, and KAT gene families in P. trichocarpa. Heterologous expression of the candidate genes in Escherichia coli and characterization of purified proteins in vitro revealed enzymatic activities similar to those described in petunia flowers. RNA interference-mediated knockdown of the CNL subfamily in gray poplar (Populus x canescens) resulted in decreased emission of C6–C1 aromatic volatiles upon herbivory, while constitutively accumulating salicinoids were not affected. This indicates the peroxisomal β-oxidative pathway participates in the formation of volatile benzenoids. The chain shortening steps for salicinoids, however, likely employ an alternative pathway.

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Zinc phosphate protects tomato plants against Pseudomonas syringae pv. tomato

Journal of Plant Diseases and Protection ◽

10.1007/s41348-021-00444-z ◽

2021 ◽

Author(s):

Mara Quaglia ◽

Marika Bocchini ◽

Benedetta Orfei ◽

Roberto D’Amato ◽

Franco Famiani ◽

...

Keyword(s):

Disease Severity ◽

Pseudomonas Syringae ◽

Zinc Phosphate ◽

Plant Defence ◽

In Planta ◽

Tomato Plants ◽

Pathogenesis Related Protein ◽

Defence Responses ◽

Plant Defence Responses

AbstractThe purpose of this study was to determine whether zinc phosphate treatments of tomato plants (Solanum lycopersicum L.) can attenuate bacterial speck disease severity through reduction of Pseudomonas syringae pv. tomato (Pst) growth in planta and induce morphological and biochemical plant defence responses. Tomato plants were treated with 10 ppm (25.90 µM) zinc phosphate and then spray inoculated with strain DAPP-PG 215, race 0 of Pst. Disease symptoms were recorded as chlorosis and/or necrosis per leaf (%) and as numbers of necrotic spots. Soil treatments with zinc phosphate protected susceptible tomato plants against Pst, with reductions in both disease severity and pathogen growth in planta. The reduction of Pst growth in planta combined with significantly higher zinc levels in zinc-phosphate-treated plants indicated direct antimicrobial toxicity of this microelement, as also confirmed by in vitro assays. Morphological (i.e. callose apposition) and biochemical (i.e., expression of salicylic-acid-dependent pathogenesis-related protein PR1b1 gene) defence responses were induced by the zinc phosphate treatment, as demonstrated by histochemical and qPCR analyses, respectively. In conclusion, soil treatments with zinc phosphate can protect tomato plants against Pst attacks through direct antimicrobial activity and induction of morphological and biochemical plant defence responses.

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Mechanistic Fingerprinting Reveals Kinetic Signatures of Resistance to Daptomycin and Host Defense Peptides in Streptococcus mitis-oralis

Antibiotics ◽

10.3390/antibiotics10040404 ◽

2021 ◽

Vol 10 (4) ◽

pp. 404

Author(s):

Michael R. Yeaman ◽

Liana C. Chan ◽

Nagendra N. Mishra ◽

Arnold S. Bayer

Keyword(s):

Flow Cytometry ◽

Host Defense ◽

Durable Resistance ◽

Cross Resistance ◽

Streptococcus Mitis ◽

Host Defense Peptides ◽

Strain Pair ◽

Defense Peptides

Streptococcus mitis-oralis (S. mitis-oralis) infections are increasingly prevalent in specific populations, including neutropenic cancer and endocarditis patients. S. mitis-oralis strains have a propensity to evolve rapid, high-level and durable resistance to daptomycin (DAP-R) in vitro and in vivo, although the mechanism(s) involved remain incompletely defined. We examined mechanisms of DAP-R versus cross-resistance to cationic host defense peptides (HDPs), using an isogenic S. mitis-oralis strain-pair: (i) DAP-susceptible (DAP-S) parental 351-WT (DAP MIC = 0.5 µg/mL), and its (ii) DAP-R variant 351-D10 (DAP MIC > 256 µg/mL). DAP binding was quantified by flow cytometry, in-parallel with temporal (1–4 h) killing by either DAP or comparative prototypic cationic HDPs (hNP-1; LL-37). Multicolor flow cytometry was used to determine kinetic cell responses associated with resistance or susceptibility to these molecules. While overall DAP binding was similar between strains, a significant subpopulation of 351-D10 cells hyper-accumulated DAP (>2–4-fold vs. 351-WT). Further, both DAP and hNP-1 induced cell membrane (CM) hyper-polarization in 351-WT, corresponding to significantly greater temporal DAP-killing (vs. 351-D10). No strain-specific differences in CM permeabilization, lipid turnover or regulated cell death were observed post-exposure to DAP, hNP-1 or LL-37. Thus, the adaptive energetics of the CM appear coupled to the outcomes of interactions of S. mitis-oralis with DAP and selected HDPs. In contrast, altered CM permeabilization, proposed as a major mechanism of action of both DAP and HDPs, did not differentiate DAP-S vs. DAP-R phenotypes in this S. mitis-oralis strain-pair.

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HopA1 Effector from Pseudomonas syringae pv syringae Strain 61 Affects NMD Processes and Elicits Effector-Triggered Immunity

International Journal of Molecular Sciences ◽

10.3390/ijms22147440 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7440

Author(s):

Shraddha K. Dahale ◽

Daipayan Ghosh ◽

Kishor D. Ingole ◽

Anup Chugani ◽

Sang Hee Kim ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Disease Susceptibility ◽

Null Mutant ◽

In Planta ◽

Host Range Expansion ◽

Unique System ◽

Effector Triggered Immunity ◽

Transcriptomic Changes ◽

Immune Detection

Pseudomonas syringae-secreted HopA1 effectors are important determinants in host range expansion and increased pathogenicity. Their recent acquisitions via horizontal gene transfer in several non-pathogenic Pseudomonas strains worldwide have caused alarming increase in their virulence capabilities. In Arabidopsis thaliana, RESISTANCE TO PSEUDOMONAS SYRINGAE 6 (RPS6) gene confers effector-triggered immunity (ETI) against HopA1pss derived from P. syringae pv. syringae strain 61. Surprisingly, a closely related HopA1pst from the tomato pathovar evades immune detection. These responsive differences in planta between the two HopA1s represents a unique system to study pathogen adaptation skills and host-jumps. However, molecular understanding of HopA1′s contribution to overall virulence remain undeciphered. Here, we show that immune-suppressive functions of HopA1pst are more potent than HopA1pss. In the resistance-compromised ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) null-mutant, transcriptomic changes associated with HopA1pss-elicited ETI are still induced and carry resemblance to PAMP-triggered immunity (PTI) signatures. Enrichment of HopA1pss interactome identifies proteins with regulatory roles in post-transcriptional and translational processes. With our demonstration here that both HopA1 suppress reporter-gene translations in vitro imply that the above effector-associations with plant target carry inhibitory consequences. Overall, with our results here we unravel possible virulence role(s) of HopA1 in suppressing PTI and provide newer insights into its detection in resistant plants.

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Further In Vitro Assessment and Mid-Term Evaluation of Control Strategy of Xylella fastidiosa subsp. pauca in Olive Groves of Salento (Apulia, Italy)

Pathogens ◽

10.3390/pathogens10010085 ◽

2021 ◽

Vol 10 (1) ◽

pp. 85

Author(s):

Giuseppe Tatulli ◽

Vanessa Modesti ◽

Nicoletta Pucci ◽

Valeria Scala ◽

Alessia L’Aurora ◽

...

Keyword(s):

Control Strategy ◽

Xylella Fastidiosa ◽

In Planta ◽

Bacterial Concentration ◽

Infected Area ◽

Olive Groves ◽

Term Evaluation ◽

In Vitro Assessment ◽

Olive Trees

During recent years; Xylella fastidiosa subsp. pauca (Xfp) has spread in Salento causing relevant damage to the olive groves. Measures to contain the spreading of the pathogen include the monitoring of the areas bordering the so-called “infected” zone and the tree eradication in case of positive detection. In order to provide a control strategy aimed to maintain the tree productivity in the infected areas, we further evaluated the in vitro and in planta mid-term effectiveness of a zinc-copper-citric acid biocomplex. The compound showed an in vitro bactericidal activity and inhibited the biofilm formation in representative strains of X. fastidiosa subspecies, including Xfp isolated in Apulia from olive trees. The field mid-term evaluation of the control strategy assessed by quantitative real-time PCR in 41 trees of two olive groves of the “infected” area revealed a low concentration of Xfp over the seasons upon the regular spraying of the biocomplex over 3 or 4 consecutive years. In particular, the bacterial concentration lowered in July and October with respect to March, after six consecutive treatments. The trend was not affected by the cultivar and it was similar either in the Xfp-sensitive cultivars Ogliarola salentina and Cellina di Nardò or in the Xfp-resistant Leccino. Moreover, the scoring of the number of wilted twigs over the seasons confirmed the trend. The efficacy of the treatment in the management of olive groves subjected to a high pathogen pressure is highlighted by the yielded a good oil production

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Sensitivity of Mycosphaerella fijiensis from Banana to Trifloxystrobin

Plant Disease ◽

10.1094/pdis.2001.85.12.1264 ◽

2001 ◽

Vol 85 (12) ◽

pp. 1264-1270 ◽

Cited By ~ 27

Author(s):

K. M. Chin ◽

M. Wirz ◽

D. Laird

Keyword(s):

Cross Resistance ◽

In Vitro Tests ◽

Mycosphaerella Fijiensis ◽

In Planta ◽

Baseline Sensitivity ◽

Single Spore ◽

Resistance Factors ◽

Development Site ◽

Disease Pressure

An ascospore germination method was developed and validated to assess the sensitivity of bulk samples of Mycosphaerella fijiensis to trifloxystrobin. Using this method, the sensitivity of 142 ascospore samples from banana plantations not treated with strobilurins was analyzed to establish a baseline of pathogen sensitivity. A bulk method was utilized for monitoring purposes because it avoids potential complications due to the isolation and propagation of single-spore isolates and enables the testing of larger samples. Following intensive use of strobilurins (6 to 11 applications per year) over 4 years, under conditions of high disease pressure and the absence of sanitary measures at a development site in Costa Rica, bulk samples with 50% effective concentration (EC50) resistance factors (RFs) in excess of 500 compared with the mean baseline sensitivity were detected. Single-ascospore isolates derived from spores germinating at the discriminatory dose of 3 μg/ml were also resistant, suggesting that the frequency of resistant individuals in bulk samples could be estimated from the relative numbers of ascospores growing at this dose. The resistance of selected isolates was confirmed in planta. In vitro tests with four resistant and two sensitive single-ascospore isolates collected from different locations and times indicated possible cross-resistance of trifloxystrobin to azoxystrobin, famoxadone, and fenamidone, but not to propiconazole.

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