scholarly journals Molecular barcoding reveals the genus Streptomyces as associated root endophytes of apple (Malus domestica) plants grown in soils affected by apple replant disease

2020 ◽  
Author(s):  
Felix Mahnkopp-Dirks ◽  
Viviane Radl ◽  
Susanne Kublik ◽  
Silvia Gschwendtner ◽  
Michael Schloter ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Apple Rootstock ◽  
Apple Replant Disease ◽  
Genus Streptomyces ◽  
Molecular Barcoding ◽  
Yield And Quality ◽  
Replant Disease ◽  
First Time ◽  
Endophytic Community

Apple replant disease (ARD) occurs when apple is repeatedly planted at the same site, leading to growth reductions and losses in fruit yield and quality. Up to now the etiology is poorly understood, but soil (micro)biota are known to be involved. Since endophytes often colonize plants via the rhizosphere this study aimed at comparing the bacterial endophytic root microbiome in plants growing in ARD affected and unaffected soils from three different sites based on greenhouse biotests using a molecular barcoding approach. The initial endophytic microbiome of the starting material (in vitro propagated plants of the apple rootstock M26) did not significantly affect the overall richness and diversity of the endophytic community in plants after 8 weeks of growth in the respective soils, but some genera of the initial microbiome managed to establish in apple roots. Proteobacteria were the dominant phylum in all samples. No differences in diversity or number of amplicon sequence variants (ASVs) between plants grown in ARD soil and unaffected soil was observed. However, several ASVs of high abundance uniquely found in plants grown in ARD affected soils were Streptomyces. In soil from all three sites these Streptomyces were negatively correlated to plant growth parameters. Future inoculation experiments using selected Streptomyces isolates have to prove if bacteria from this genus are opportunists or part of the ARD complex. For the first time, the bacterial endophytic community of apple roots grown in ARD affected soils was characterized which will help to understand the etiology of ARD and develop countermeasures.

Formation and exudation of biphenyl and dibenzofuran phytoalexins by roots of the apple rootstock M26 grown in apple replant disease soil

2021 ◽  
Vol 192 ◽  
pp. 112972
Author(s):  
Belnaser A. Busnena ◽  
Till Beuerle ◽  
Felix Mahnkopp-Dirks ◽  
Traud Winkelmann ◽  
Ludger Beerhues ◽  
...  
Keyword(s):  
Apple Rootstock ◽  
Apple Replant Disease ◽  
Replant Disease

scholarly journals Isolation and potential biocontrol of the fungus causing anthracnose in longan in Vietnam

2021 ◽  
Vol 24 (1) ◽  
pp. 1889-1896
Author(s):  
Phan Thi Huyen ◽  
Vo Thi Xuan Huong ◽  
Do Thanh Nhan
Keyword(s):  
Human Health ◽  
Economic Value ◽  
Culture Method ◽  
Fungal Species ◽  
Yield And Quality ◽  
Wide Range ◽  
Microbial Community Structures ◽  
Increasing Demand ◽  
First Time

Introduction: Longan is a crop plant of very high economic value, and both its fruit and flower are beneficial for human health. Longan has been increasingly cultivated in Vietnam due to the increasing demand for domestic consumption as well as export of its fruit. However, the widespread emergence and spread of anthracnose, a group of fungal disease affecting a wide range of plant species, in longan has seriously affected both the longan fruit yield and quality in Vietnam. Current methods for the prevention of anthracnose in longan depend mainly on the use of fungicides which are very harmful to human health as well as disruptive to microbial community structures in different ecosystems. In order to obtain an environmentally friendly method of control for this disease, the agent causing anthracnose in longan must first be identified. Therefore, the aim of this study was to isolate and identify the causal anthracnose agent in longan in Vietnam. Methods: Experiments were first carried out with pieces of anthracnose longan leaves pressed onto the surface of potato-dextrose agar (PDA) and incubated for days at 30◦C. Colonies, varying in appearance, were repeatedly isolated and purified on PDA agar, and the anthracnose-causing agent was initially recognized on the basis of colony characteristics and cell morphology. The suspected isolate was then tested for its ability to decompose healthy longan leaf in vitro, and its rDNA region was cloned and sequenced to determine its taxonomy. Antifungal activity testing was performed using the co-culture method. Results: We obtained a fungal isolate with septate hyphae, ovoid appressoria, and conidia (which were cylindrical in shape with rounded ends). This isolate showed a clear ability to decompose healthy longan leaves. At the molecular level, the isolate was determined to be a fungal species belonging to genus Colletotrichum, and therefore named Colletotrichum sp. strain BKHCM. We also found that its growth was inhibited when co-cultured with Streptomyces flaveus, an actinomycete originating from soil. Conclusion: For the first time, we isolated a fungal species belonging to genus Colletotrichum from anthracnose-infected longan leaves in Vietnam. We also showed that the growth of this fungus could potentially be biocontrolled.

scholarly journals Interaction of Brassicaceae Seed Meal Soil Amendment and Apple Rootstock Genotype on Microbiome Structure and Replant Disease Suppression

2019 ◽  
Vol 109 (4) ◽  
pp. 607-614 ◽  
Author(s):  
Likun Wang ◽  
Mark Mazzola
Keyword(s):  
Disease Suppression ◽  
Seed Meal ◽  
Effective Control ◽  
Tree Biomass ◽  
Apple Rootstock ◽  
Apple Replant Disease ◽  
Rhizosphere Microbiome ◽  
Replant Disease ◽  
Application Rates ◽  
Orchard Soil

Preplant soil application of a Brassica juncea–Sinapis alba seed meal formulation (SM) at a rate of 6.6 t ha−1 alters composition of the orchard soil microbiome in a manner that yields sustainable long-term suppression of soilborne pathogens in apple production systems. However, the cost of SM amendment has hindered the adoption of this tactic to manage apple replant disease in commercial orchards. Greenhouse trials were conducted to assess the effect of reduced SM application rates in concert with apple rootstock genotype on structure of the rhizosphere microbiome and associated disease control outcomes. At all application rates assessed, SM treatment increased tree growth and reduced disease development relative to the control. In general, total tree biomass and leader shoot length were similar in soils treated with SM at 4.4 or 6.6 t ha−1 regardless of rootstock genotype. Equivalent increase in tree biomass when cultivated in soil treated at the lowest and highest SM amendment rate was attained when used in conjunction with G.41 or G.210 apple rootstocks. Suppression of Pythium spp. or Pratylenchus penetrans root densities was similar at all SM application rates. When cultivated in nontreated replant orchard soil, Geneva rootstocks (G.41 and G.210) exhibited lower levels of Pythium spp. and P. penetrans root colonization relative to Malling rootstocks (M.9 and MM.106). For a given rootstock, structure of the rhizosphere microbiome was similar in soils treated with SM at 4.4 and 6.6 t ha−1. G.41 and G.210 rootstocks but not M.9 or MM.106 cultivated in soil treated with SM at 2.2 t ha−1 possessed a rhizosphere bacterial community structure that differed significantly from the control. Findings indicate that effective control of apple replant disease may be attained at lower SM amendment rates than employed previously, with lower effective rates possible when integrated with tolerant rootstock genotypes such as G.41 or G.210.

scholarly journals Detection of Above-Ground Physiological Indices of an Apple Rootstock Superior Line 12-2 with Improved Apple Replant Disease (ARD) Resistance

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 337
Author(s):  
Yunfei Mao ◽  
Yijun Yin ◽  
Xueli Cui ◽  
Haiyan Wang ◽  
Xiafei Su ◽  
...  
Keyword(s):  
Chlorophyll Content ◽  
Apple Rootstock ◽  
Apple Replant Disease ◽  
Replant Disease ◽  
Physiological Indices ◽  
Reduced Nitrogen ◽  
June July ◽  
Relative Chlorophyll Content

(1) Background: The cultivation of resistant rootstocks is an effective way to prevent ARD. (2) Methods: 12-2 (self-named), T337, and M26 were planted in replanted and sterilized soil. The aboveground physiological indices were determined. (3) Results: The plant heights and the stem thicknesses of T337 and M26 were significantly affected by ARD. Relative chlorophyll content (June–October), Pn (August–September), and Gs (August) of T337 and relative chlorophyll content (June–July, September), Pn (September–October), and Ci (September) of M26 were significantly affected by ARD. ARD had a significant effect on Fv/Fm (June), qP (June–July), and NPQ of T337 (June–October, except August) and Fv/Fm (June) and NPQ (June-October, except July) of M26. Additionally, ARD affected Rfd of M26 and T337 during August. SOD (August and October), POD (August–September), and CAT (July-August, October) activities and MDA (September–October) content of T338 as well as SOD (July–October), POD (June–October), and CAT (July-October) activities and MDA (July, September–October) content of M26 were significantly affected by ARD. ARD significantly reduced nitrogen (October), phosphorus (September–October), and zinc (July) contents of M26 and potassium (June) content of T337. The above physiological indices were not affected by ARD in 12-2. (4) Conclusions: 12-2 could be useful as an important rootstock to relieve ARD due to strong resistance.

scholarly journals Arbuscular mycorrhiza improve apple rootstock growth in soil conducive to specific apple replant disease

2008 ◽  
Vol 61 ◽  
pp. 48-53
Author(s):  
H.J. Ridgway ◽  
J. Kandula ◽  
A. Stewart
Keyword(s):  
Beneficial Effect ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Dry Weight ◽  
Shoot Length ◽  
Apple Rootstock ◽  
Apple Replant Disease ◽  
Beneficial Effects ◽  
Replant Disease ◽  
Species Specific

Specific apple replant disease (SARD) impairs the growth and establishment of trees in replanted apple orchards Apple roots are normally colonised by arbuscular mycorrhizal fungi (AMF) which may have beneficial effects on plant growth Four AMF inoculation treatments (three species of AMF Glomus mosseae Acaulospora laevis and Scutellospora calospora and an uninoculated control) were applied to M26 apple rootstock seedlings in SARD and nonSARD soil Of the fungi inoculated S calospora had the greatest beneficial effect in improving shoot and root dry weight and shoot length in SARD soil More disease symptoms occurred on main and feeder roots in SARD soil and none of the inoculated AMF fungi reduced these Both A laevis and S calospora significantly increased shoot length and gave a higher percentage of AMFcolonised roots in nonSARD soil These results showed that AMF improve tolerance of apple to SARD and indicate that the beneficial effect is species specific Characterisation of endogenous mycorrhizae in the soil identified S pellucida This is a new species record for New Zealand and provides the opportunity to determine whether the beneficial effect is specific to the genus Scutellospora

Apple rootstock evaluation for apple replant disease

2016 ◽  
pp. 425-430 ◽  
Author(s):  
D. Kviklys ◽  
T.L. Robinson ◽  
G. Fazio
Keyword(s):  
Apple Rootstock ◽  
Apple Replant Disease ◽  
Replant Disease

scholarly journals Interaction of Brassicaceous Seed Meal and Apple Rootstock on Recovery of Pythium spp. and Pratylenchus penetrans from Roots Grown in Replant Soils

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Mark Mazzola ◽  
Jack Brown ◽  
Xiaowen Zhao ◽  
Antonio D. Izzo ◽  
Gennaro Fazio
Keyword(s):  
Disease Suppression ◽  
Seed Meal ◽  
Pratylenchus Penetrans ◽  
Root Infection ◽  
Apple Rootstock ◽  
Apple Rootstocks ◽  
Apple Replant Disease ◽  
Pythium Irregulare ◽  
Replant Disease ◽  
Lesion Nematode

Pythium spp. and Pratylenchus penetrans are significant components of the diverse pathogen complex that incites apple replant disease in Washington State. The structure of the Pythium population differs among orchard soils but is composed of multiple pathogenic species. Studies were conducted to determine the effect of brassicaceous seed meals and apple rootstock on the activity and composition of these pathogen populations. Brassicaceous seed meals differed in capacity to suppress Pythium numbers and apple root infection, as well as differentially transformed composition of the population recovered from apple roots. Brassica juncea seed meal (SM) was the sole seed meal examined to suppress Pythium numbers and root infection; however, a persisting population was always detected in which Pythium irregulare existed as the dominant or co-dominant species. In general, the Geneva series rootstocks were less susceptible to root infection by native populations of Pythium, whereas M26, MM106, and MM111 were highly susceptible. Apple rootstocks from the Geneva series consistently supported lower populations of P. penetrans than did Malling or Malling-Merton rootstocks. B. juncea SM was superior to Brassica napus SM or Sinapis alba SM in suppressing lesion nematode populations. Significant rootstock × seed meal interaction was detected, and nematode suppression in response to B. napus or S. alba SM was only observed when used in concert with a tolerant rootstock, while B. juncea SM suppressed lesion nematode root populations irrespective of rootstock. These findings demonstrate that utilization of brassicaceous seed meal amendments for replant disease suppression must employ an appropriate rootstock in order to achieve optimal disease control.

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

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