scholarly journals Alleviation of Nematode-Mediated Apple Replant Disease by Pre-Cultivation of Tagetes

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 433
Author(s):  
Xorla Kanfra ◽  
Taye Obawolu ◽  
Andreas Wrede ◽  
Bernhard Strolka ◽  
Traud Winkelmann ◽  
...  
Keyword(s):  
Parasitic Nematodes ◽  
Tagetes Patula ◽  
Plant Parasitic Nematodes ◽  
Apple Rootstocks ◽  
Base Diameter ◽  
Apple Replant Disease ◽  
Severe Problem ◽  
Replant Disease ◽  
Control Option ◽  
Shoot Base

Apple replant disease (ARD) is a severe problem in orchards and tree nurseries caused by yet unknown soil biota that accumulate over replanting cycles. This study tested the contribution of nematodes to ARD, and cultivation of Tagetes as a control option. In a pot experiment, Tagetes patula or Tagetes tenuifolia were grown in ARD soil, incorporated or removed. Nematodes extracted from untreated ARD soil and washed on 20-µm sieves induced ARD symptoms when inoculated to apple plantlets growing in a sterile substrate. In contrast, nematodes from Tagetes treated ARD soil did not reduce root growth compared to uninoculated plants, irrespective of Tagetes species and incorporation. In plots of five apple tree nurseries or orchards, either Tagetes or grass was grown on ARD soil. Nematodes extracted from the grass plots and inoculated to apple plantlets significantly reduced plant growth compared to nematodes from Tagetes plots for all five farms. Apple rootstocks showed overall a significantly higher increase in shoot base diameter when grown on Tagetes-treated plots compared to grass plots, while this effect differed among farms. Plant-parasitic nematodes were too low in abundance to explain plant damage. In conclusion, Tagetes alleviated ARD by changing the nematode community in soil.

Alleviation of Nematode-Mediated Apple Replant Disease by Pre-Cultivation of Tagetes

2021 ◽  
Author(s):  
Xorla Kanfra ◽  
Taye Obawolu ◽  
Andreas Wrede ◽  
Bernhard Strolka ◽  
Traud Winkelmann ◽  
...  
Keyword(s):  
Parasitic Nematodes ◽  
Tagetes Patula ◽  
Plant Parasitic Nematodes ◽  
Apple Rootstocks ◽  
Base Diameter ◽  
Free Living ◽  
Apple Replant Disease ◽  
Severe Problem ◽  
Replant Disease ◽  
Shoot Base

Apple replant disease (ARD) is a severe problem in orchards and tree nurseries caused by yet unknown soil biota that accumulate over replanting cycles. This study tested the contribution of nematodes to ARD, and cultivation of Tagetes as a control option. In a pot experiment, Tagetes patula or Tagetes tenuifolia were grown in ARD soil, incorporated or removed. Nematodes extracted from untreated ARD soil and washed on 20 µm-sieves induced ARD symptoms when inoculated to apple saplings growing in a sterile substrate. In contrast, nematodes from Tagetes treated ARD soil did not reduce root growth compared to uninoculated plants, irrespective of Tagetes species and incorporation. In plots of five apple tree nurseries or orchards, either Tagetes or grass was grown on ARD soil. Nematodes extracted from the grass plots and inoculated to apple saplings significantly reduced plant growth compared to nematodes from Tagetes plots for all five farms. Apple rootstocks showed overall a significantly higher increase in shoot base diameter when grown on Tagetes-treated plots compared to grass plots, while this effect differed among farms. Plant-parasitic nematodes were too low in abundance to explain plant damage. In conclusion, the free-living nematodes involved in ARD can be controlled by Tagetes.

Root exposure to apple replant disease soil triggers local defense response and rhizoplane microbiome dysbiosis

2021 ◽  
Author(s):  
Alicia Balbín-Suárez ◽  
Samuel Jacquiod ◽  
Annmarie-Deetja Rohr ◽  
Benye Liu ◽  
Henryk Flachowsky ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plant Defense ◽  
Defense Response ◽  
Soil Column ◽  
Soil Layer ◽  
Soil Microbiome ◽  
Control Soil ◽  
Apple Rootstocks ◽  
Apple Replant Disease ◽  
Replant Disease

Abstract A soil column split-root experiment was designed to investigate the ability of apple replant disease (ARD) causing agents to spread in soil. ‘M26’ apple rootstocks grew into a top layer of Control soil, followed by a barrier-free split-soil layer (Control soil/ARD soil). We observed a severely reduced root growth, concomitant with enhanced gene expression of phytoalexin biosynthetic genes and phytoalexin content in roots from ARD soil, indicating a pronounced local plant defense response. Amplicon sequencing (bacteria, archaea, fungi) revealed local shifts in diversity and composition of microorganisms in the rhizoplane of roots from ARD soil. An enrichment of OTUs affiliated to potential ARD fungal pathogens (Ilyonectria and Nectria sp.) and bacteria frequently associated with ARD (Streptomyces, Variovorax) was noted. In conclusion, our integrated study supports the idea of ARD being local and not spreading into surrounding soil, as only the roots in ARD soil were affected in terms of growth, phytoalexin biosynthetic gene expression, phytoalexin production, and altered microbiome structure. This study further reinforces the microbiological nature of ARD, being likely triggered by a disturbed soil microbiome enriched with low mobility ARD-causing agents that induce a strong plant defense and rhizoplane microbiome dysbiosis, concurring with root damage.

scholarly journals Reduced microbial potential for the degradation of phenolic compounds in the rhizosphere of apple plantlets grown in soils affected by replant disease

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Viviane Radl ◽  
Jana Barbro Winkler ◽  
Susanne Kublik ◽  
Luhua Yang ◽  
Traud Winkelmann ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Relative Abundance ◽  
Aromatic Compounds ◽  
Pathogenic Fungi ◽  
Nutrient Sensing ◽  
Soil Microbiome ◽  
Apple Rootstocks ◽  
Apple Replant Disease ◽  
Metagenome Analysis ◽  
Replant Disease

Abstract Background Apple replant disease (ARD) is a syndrome that occurs in areas where apple plants or closely related species have been previously cultivated. Even though ARD is a well-known phenomenon, which has been observed in different regions worldwide and occurs independent of the soil type, its causes still remain unclear. Results As expected, the biomass of plants grown in replant soil was significantly lower compared to those grown in control (virgin) soil. A shotgun metagenome analysis showed a clear differentiation between the rhizosphere and bulk soil compartments independent from the soil used. However, significant differences associated with apple replant disease were only observed in the rhizosphere compartment, for which we detected changes in the abundance of major bacterial genera. Interestingly, reads assigned to Actinobacteria were significantly reduced in relative abundance in rhizosphere samples of the soil affected by replant disease. Even though reads assigned to pathogenic fungi were detected, their relative abundance was low and did not differ significantly between the two different soils. Differences in microbiome structure also resulted in shifts in functional pattern. We observed an increase in genes related to stress sensing in the rhizosphere of soils affected by replant disease, whereas genes linked to nutrient sensing and uptake dominated in control soils. Moreover, we observed a lower abundance of genes coding for enzymes which trigger the degradation of aromatic compounds in rhizosphere of soils affected by replant disease, which is probably connected with higher concentration of phenolic compounds, generally associated with disease progression. Conclusions Our study shows, for the first time, how apple replanting affects soil functioning by altering the soil microbiome. Particularly, the decrease in the abundance of genes which code for enzymes catalyzing the degradation of aromatic compounds, observed in the rhizosphere of plants grown in soil affected by apple replant disease, is of interest. Apple rootstocks are known to synthetize many phenolic compounds, including defense related phytoalexins, which have been considered for long to be connected with the emergence of replant disease. The knowledge gained in this study might help to develop targeted strategies to overcome or at least reduce the effects of ARD symptoms.

Exploring microbial determinants of apple replant disease (ARD): a microhabitat approach under split-root design

2020 ◽  
Vol 96 (12) ◽  
Author(s):  
Alicia Balbín-Suárez ◽  
Maik Lucas ◽  
Doris Vetterlein ◽  
Søren J Sørensen ◽  
Traud Winkelmann ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Microbial Community Composition ◽  
Rrna Gene ◽  
Apple Rootstocks ◽  
Apple Replant Disease ◽  
Alpha And Beta Diversity ◽  
Replant Disease ◽  
Split Root ◽  
And Control

ABSTRACT Apple replant disease (ARD) occurs worldwide in apple orchards and nurseries and leads to a severe growth and productivity decline. Despite research on the topic, its causality remains unclear. In a split-root experiment, we grew ARD-susceptible ‘M26’ apple rootstocks in different substrate combinations (+ARD: ARD soil; -ARD: gamma-irradiated ARD soil; and Control: soil with no apple history). We investigated the microbial community composition by 16S rRNA gene amplicon sequencing (bacteria and archaea) along the soil–root continuum (bulk soil, rhizosphere and rhizoplane). Significant differences in microbial community composition and structure were found between +ARD and -ARD or +ARD and Control along the soil–root continuum, even for plants exposed simultaneously to two different substrates (-ARD/+ARD and Control/+ARD). The substrates in the respective split-root compartment defined the assembly of root-associated microbial communities, being hardly influenced by the type of substrate in the respective neighbor compartment. Root-associated representatives from Actinobacteria were the most dynamic taxa in response to the treatments, suggesting a pivotal role in ARD. Altogether, we evidenced an altered state of the microbial community in the +ARD soil, displaying altered alpha- and beta-diversity, which in turn will also impact the normal development of apple rhizosphere and rhizoplane microbiota (dysbiosis), concurring with symptom appearance.

scholarly journals Suppression of soil borne fungal pathogens associated with apple replant disease by cyclic application of native strains of Pseudomonas aeruginosa

2017 ◽  
Vol 9 (4) ◽  
pp. 2105-2109
Author(s):  
Ranjna Sharma ◽  
Joginder Pal ◽  
Sheetal Rana ◽  
Mohinder Kaur
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Plant Growth ◽  
Fungal Pathogens ◽  
Pythium Ultimum ◽  
Apple Rootstocks ◽  
Fungal Population ◽  
Apple Replant Disease ◽  
Replant Disease ◽  
Plant Growth Promoting ◽  
Growth Promoting

Plant growth promoting fluorescent Pseudomonas aeruginosa strains An-E and An- F were used for the suppression of replant disease organisms which were isolated from replant site of apple in Shimla district of Hima-chal Pradesh. Full and half concentration of individual and consortial strains were used for the experiment. Among all the treatments, full concentration of compatible consortial strains were quite effective in decreasing the deleterious rhizobacterial (197-99 cfu/g) and fungal population (7-0 cfu/g). Total rhizobacterial count starts decreasing after each cyclic application of fluorescent P. aeruginosa strains An-E and An-F due to root colonization property of these plant growth promoting strains in the replant site of apple. Establishment of Pseudomonas aeruginosa strains at replant site was inversely correlated with decreasing deleterious bacterial and fungal population in the replant site. 70 per cent survival of apple rootstocks was recorded in full concentration of consortial treatment (An-E and An- F) as compared to control after three years of plantation. Four major fungal pathogens viz. Dematophor anecatrix, Phytophthora cactorum, Pythium ultimum and Fusarium oxysporum were isolated and identified from National centre for fungal taxonomy, New Delhi. These strains can be further exploited and recommended for the management of replant problem of apple.

Potential for the Pathogenicity of Plant-Parasitic Nematodes Associated with Blueberries in Georgia and North Carolina

2020 ◽  
Vol 21 (1) ◽  
pp. 9-12
Author(s):  
Paul M. Severns ◽  
Ganpati B. Jagdale ◽  
Ted Holladay ◽  
Phillip M. Brannen ◽  
Jim P. Noe ◽  
...  
Keyword(s):  
North Carolina ◽  
Relative Abundance ◽  
Indicator Species ◽  
Parasitic Nematodes ◽  
Indicator Species Analysis ◽  
Plant Parasitic Nematodes ◽  
Replant Disease ◽  
Species Analysis ◽  
Plant Parasitic ◽  
Ring Nematode

Ring (Mesocriconema ornatum) nematode in Georgia (GA) has been associated with blueberry replant disease. A survey of plant-parasitic nematodes (PPNs) from production blueberry fields in GA and North Carolina (NC) was previously presented and evaluated from an abundance perspective. However, PPNs are often patchily distributed, occurring in close physical association with infected plant roots. Soil cores may or may not sample the areas of high nematode abundance, and nematode counts tend to be highly variable because of this patchiness. To evaluate the survey data for potentially unrecognized blueberry PPNs, we reanalyzed nematode survey data from NC and GA using multivariate analyses that integrate both patterns of occurrence and patterns in relative abundance. Indicator species analysis identified ring nematode in GA as a potentially pathogenic nematode, consistent with previous confirmation of pathogenicity through a container study. Indicator species analysis also identified two potentially pathogenic nematodes in NC blueberries: awl (Dolichodorus spp.) and sheath (Hemicycliophora spp.) nematodes. Of the two nematodes, awl shared a similar position in the NC blueberry nematode community when compared with ring nematode in GA. However, awl nematode relative abundance was low enough, when compared with ring nematode in GA, to suggest that although it is likely parasitic on NC blueberries, it may not be pathogenic. Our analysis from a previous survey suggests that PPNs are unlikely to be a threat to NC blueberry production. However, if blueberry replant disease emerges in NC, then ring, awl, and sheath nematodes should be considered as potential causal agents.

scholarly journals Screening Malus Germplasm for Field Resistance to Apple Replant Disease and Root-lesion Nematodes

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 618f-618
Author(s):  
D.K. Isutsa ◽  
I.A. Merwin ◽  
B.B. Brodie
Keyword(s):  
Cover Crops ◽  
Dry Mass ◽  
Parasitic Nematodes ◽  
Screening Methods ◽  
Apple Replant Disease ◽  
Replant Disease ◽  
Lesion Nematodes ◽  
Root Necrosis ◽  
Root Lesion Nematodes ◽  
Plant Dry Mass

Apple replant disease (ARD) is a serious problem in fruit production, and none of the major clonal rootstocks are resistant to ARD. We have screened Malus domestica clones and species accessions from the USDA Malus Germplasm Repository at Geneva, N.Y., including M. angustifolia-2375.03 (MA), M. coronaria-2966.01 (MC), M. fusca-3031.01 (MF), M. ioensis-3059.01 (MI), M. sieversii-3530.01 (MS), and M. kirghisorum-3578.01 (MK), for resistance to ARD and root-lesion nematodes (RLN, Pratylenchus spp.), in a composite soil collected from 11 New York orchards with known ARD. Plant dry mass and height, root necrosis, and nematode populations in different apple species and clones were compared after 60 days growth in steam-pasteurized (PS), RLN-inoculated (IS), and naturally infested field (FS) soils with 1200 RLN per 100 cm3. More severe stunting, reduced plant dry mass, and root necrosis occurred in FS seedlings compared with those in PS, but M. angustifolia seedlings were substantially more resistant or tolerant to RLN and ARD than the other species tested. Plant dry mass ranked MK>MS>MA>MI>MF>MC, and these differences were significant at the 5% level. RLN root populations were negatively correlated with plant dry mass, and accounted for about 10% of its variation, with nematode populations in roots ranking MC>MF>MK>MI>MS>MA. Useful resistance to ARD and parasitic nematodes apparently exists within Malus germplasm collections, and can be identified by testing more genotypes, developing rapid resistance screening methods, and comparing RLN host preferences among Malus genotypes and various orchard cover crops.

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