scholarly journals The Endophytic Strain Trichoderma asperellum 6S-2: An Efficient Biocontrol Agent against Apple Replant Disease in China and a Potential Plant-Growth-Promoting Fungus

2021 ◽  
Vol 7 (12) ◽  
pp. 1050
Author(s):  
Haiyan Wang ◽  
Rong Zhang ◽  
Yanan Duan ◽  
Weitao Jiang ◽  
Xuesen Chen ◽  
...  
Keyword(s):  
Plant Growth ◽  
Malus Domestica ◽  
Lateral Roots ◽  
Pathogenic Fungi ◽  
Apple Orchard ◽  
Fusarium Proliferatum ◽  
Trichoderma Asperellum ◽  
Apple Replant Disease ◽  
Volatile Substances ◽  
Replant Disease

A study was conducted for endophytic antagonistic fungi obtained from the roots of healthy apple trees growing in nine replanted orchards in Shandong Province, China. The fungi were assessed for their ability to inhibit Fusarium proliferatum f. sp. malus domestica MR5, a fungal strain associated with apple replant disease (ARD). An effective endophyte, designated as strain 6S-2, was isolated and identified as Trichoderma asperellum. Strain 6S-2 demonstrated protease, amylase, cellulase, and laccase activities, which are important for the parasitic and antagonistic functions of pathogenic fungi. The inhibition rate of 6S-2 against Fusarium proliferatum f. sp. malus domestica MR5 was 52.41%. Strain 6S-2 also secreted iron carriers, auxin, ammonia and was able to solubilize phosphorus. Its fermentation extract and volatile substances inhibited the growth of MR5, causing its hyphae to twist, shrink, swell, and rupture. The antifungal activity of the 6S-2 fermentation extract increased with increasing concentrations. It promoted the production and elongation of Arabidopsis thaliana lateral roots, and the strongest effects were seen at a concentration of 50 mg/mL. A GC-MS analysis of the 6S-2 fermentation extract and volatile substances showed that they comprised mainly alkanes, alcohols, and furanones, as well as the specific volatile substance 6-PP. The application of 6S-2 spore suspension to replanted apple orchard soils reduced plant oxidative damage and promoted plant growth in a pot experiment. Therefore, the endophytic strain T. asperellum 6S-2 has the potential to serve as an effective biocontrol fungus for the prevention of ARD in China, and appears to promote plant growth.

Transcriptomic analysis of molecular responses in Malus domestica ‘M26’ roots affected by apple replant disease

2017 ◽  
Vol 94 (3) ◽  
pp. 303-318 ◽  
Author(s):  
Stefan Weiß ◽  
Melanie Bartsch ◽  
Traud Winkelmann
Keyword(s):  
Malus Domestica ◽  
Transcriptomic Analysis ◽  
Apple Replant Disease ◽  
Molecular Responses ◽  
Replant Disease

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.

Impact of cover crop in pre-plant of apple orchards: relationship between crop health, root inhabiting fungi and rhizospheric bacteria

2015 ◽  
Vol 95 (5) ◽  
pp. 947-958 ◽  
Author(s):  
L. M. Manici ◽  
M. Kelderer ◽  
F. Caputo ◽  
F. Nicoletti ◽  
F. De Luca Picione ◽  
...  
Keyword(s):  
Plant Growth ◽  
Cover Crops ◽  
Cover Crop ◽  
Apple Orchard ◽  
Infection Frequency ◽  
Apple Orchards ◽  
Rhizospheric Bacteria ◽  
Replant Disease ◽  
Crop Health

Manici, L. M., Kelderer, M., Caputo, F., Nicoletti, F., De Luca Picione, F. and Topp A. R. 2015. Impact of cover crop in pre-plant of apple orchards: relationship between crop health, root inhabiting fungi and rhizospheric bacteria. Can. J. Plant Sci. 95: 947–958. Replant disease of fruit tree orchards has a multifactorial etiology, mainly due to the decline in soil biodiversity along with an increase in root rot pathogens, which can be principally countered with appropriate cropping practices. Therefore, a study on the impact of cover crops on plant health of young fruit trees in long-term orchards was performed. Bioassays were performed over two consecutive growing cycles using soil from a multigeneration apple orchard affected by replant disease. First, a cycle was performed with three cover crops (alfalfa, barley, marigold) and apple rootstock plantlets; at the end, the above-ground part of the plant was removed and root residues left in the soil. In the second cycle, an apple orchard planting was simulated upon the first experimental design. Changes of diversity and composition of root inhabiting fungi and rhizospheric bacteria were evaluated as well as apple plant growth response to the pre-plant treatments. Results suggest that one cycle with alternate plants was sufficient to induce changes at the rhizosphere level, despite soil microbial resilience caused by the same long-term soil management. Rhizospheric bacteria were generally affected by plant genotype. Findings suggest that all three different cover crops can harbor almost all fungal species that colonize apple in replanted orchards (Fusarium spp., Pythum spp., binucleate Rhizoctonia sp., Cylindrocarpon-like-fungi and a several nonpathogenic saprophytic fungi named “other”), but their infection frequency varied according to the host plant. A single pre-plant break treatment did not overall differ significantly in plant growth of subsequent apple tree; however, break with marigold, which increased abundance of nonpathogenic root inhabiting fungi more than other cover crops, gave significantly higher plant growth than obtained after barley. This study provides evidence about cover-crop potential to increase soil diversity in long-term permanent cropping systems and to manipulate root colonizing fungi involved in crop health.

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.

scholarly journals Impaired defense reactions in apple replant disease-affected roots of Malus domestica ‘M26’

2017 ◽  
Vol 37 (12) ◽  
pp. 1672-1685 ◽  
Author(s):  
Stefan Weiß ◽  
Benye Liu ◽  
Dennis Reckwell ◽  
Ludger Beerhues ◽  
Traud Winkelmann
Keyword(s):  
Malus Domestica ◽  
Apple Replant Disease ◽  
Replant Disease ◽  
Defense Reactions

Performance evaluation of locally available composts to reduce replant disease in apple orchards of central Europe

2018 ◽  
Vol 34 (6) ◽  
pp. 543-557 ◽  
Author(s):  
Ingrid H. Franke-Whittle ◽  
Marina Fernández-Delgado Juárez ◽  
Heribert Insam ◽  
Simon Schweizer ◽  
Andreas Naef ◽  
...  
Keyword(s):  
Plant Growth ◽  
Bacterial Communities ◽  
Growth Response ◽  
Organic Matter Content ◽  
Research Station ◽  
Growth Responses ◽  
Apple Replant Disease ◽  
Amended Soils ◽  
Replant Disease ◽  
Plant Growth Response

AbstractA study on locally available composts in Austria, Germany, Italy and Switzerland was conducted to investigate the potential of these non-chemical based tools to increase soil health in orchards afflicted by apple replant disease (ARD). A total of 26 different composts (six to seven per country) were chosen for the study. Composts were divided into ten types according to the waste materials used as substrates in the composting process. Growth reduction is the main symptom associated with replant disease; therefore compost performance was evaluated based on the growth responses of apple rootstock plantlets in compost-amended soils in pots. These greenhouse trials were performed in one research station per country, located in an intensive apple-growing area, and soil was taken from an apple orchard affected by replanting disease. Plant growth response was measured as shoot elongation at the end of each greenhouse trial, and results showed increases in growth compared with the respective controls of 2–26% in 20 out of 26 composts evaluated. The heterogeneous nature of the composts most likely attributed to the finding that similar compost types originating from the different countries had varying effects on plant growth. Overall, no significant changes in chemical and biological properties were observed in amended soils as compared with non-amended controls. The high soil resilience was in part expected given the good organic matter content in the original soils (>2%). The bacterial communities of the composts were investigated using the COMPOCHIP microarray, and analyses showed that differences in plant growth response were mainly attributed to the microbial changes introduced into the soil through composts rather than to changes in soil chemical and biological parameters. However, the bacterial communities of composts appeared to be more influenced by geographical origin than by compost type. The results have shown that soil amendment with composts generated from locally produced wastes have the potential to reduce the effects of ARD, although the effects appear to be both compost and soil specific.

scholarly journals Biocontrol Potential of The Phloridin-Degrading Bacillus Licheniformis XNRB-3 Against Apple Replant Disease

2021 ◽  
Author(s):  
Duan Yanan ◽  
Zhao Lei ◽  
Jiang Weitao ◽  
Chen Ran ◽  
Zhang Rong ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Phenolic Acids ◽  
Bacillus Licheniformis ◽  
Pathogenic Fungi ◽  
Effective Control ◽  
Control Effect ◽  
Apple Replant Disease ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Replant Disease

Abstract Background: Apple replant disease (ARD) is a common occurrence in many major apple-growing areas worldwide, seriously hindering the development of the apple industry. To avoid the shortcomings of chemical fungicides currently used to control ARD, it is necessary to find sustainable and effective control methods. Here, an endophytic phloridin-degrading Bacillus licheniformis XNRB-3 was isolated from the root tissue of healthy apple trees, and its control effect on apple replant disease (ARD) and its how to alleviates the pathogen pressure via changes in soil microbiomes were studied.Results: The addition of strain XNRB-3 in Fusarium infested soils significantly reduced the number of pathogens in the soil, thus resulting in a lower disease incidence, and the relative control effect reached more than 60%. The fermentation broth can also protect the roots of the plants from Fusarium infection. These antagonistic effects were further validated using an in vitro assay in which the pathogen control was related to growth and spore germination inhibition via directly secreted antimicrobial substances and and indirect interspecific competition for nutrients. The antifungal organic compounds in the fermentation metabolites were identified using GC-MS technology. Among them, alpha-bisabolol and 2,4-di-tert-butylphenol had significant inhibitory effects on many planted pathogenic fungi. Butanedioic acid, monomethyl ester, and dibutyl phthalate can promote the root elongation and lateral root development of Arabidopsis plants. The potential of strain XNRB-3 to control ARD was later validated using microbial fertilizer inoculation in pot and field experiment. The addition of strain XNRB-3 significantly promoted the growth of plants, and the activity of enzymes related to disease resistance (SOD, POD, and CAT) was also significantly enhanced. It also reduced the abundance of Fusarium and the content of phenolic acids in the rhizosphere soil, improved soil microbial community structure and nutritional conditions, and increased soil microbial diversity and activity, as well as soil enzyme activity. Conclusions: The incorporation of strain XNRB-3 in the soil alleviated the damage of soil-borne pathogens to plants by reducing the relative abundance of pathogenic fungi and the content of phenolic acids, and inducing disease resistance of plants. Taken together, B. licheniformis XNRB-3 could be developed into a promising biocontrol and plant-growth-promoting agent. This provides a new management strategy to control ARD.

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.

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