Understanding the Parasitic Variability of the Northern Root Knot Nematode (Meloidogyne Hapla) Through Multidisciplinary Approaches of Soil Biome and Environment PDF Download
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Author: Isaac Lartey Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 0
Book Description
Managing Meloidogyne hapla remains challenging due to the ban of broad-spectrum nematicides, lack of resistant crops and its broad host range. It also has parasitic variability (PV) where populations (pop) are morphologically and genetically similar but vary in pathogenicity and reproductive potential. Although PV in M. hapla appears to have some relationship to soil types, what soil conditions favor its PV and/or its distribution are unknown. The goal of my research was to understand the soil conditions where M. hapla PVexist by quantifying the biophysicochemical (BPC) conditions from the ecosystem down to microbiome level. I designed observational and experimental approaches and tested four objectives. First, was to evaluate the association between soil conditions and M. hapla distribution at the ecosystem level. My hypothesis was that the presence of M. hapla will be associated with degraded soil conditions. I selected 15 (6 muck and 9 mineral soil)agricultural fields with adjacent natural vegetation in southwest, northwest and eastern regions of the lower peninsula of Michigan as study sites. I collected a total of 75 (5 per field)georeferenced soil samples from agricultural fields and equal number from adjacent natural vegetation soils, quantified the soil food web (SFW) conditions using the Ferris SFW model, and screened for M. hapla presence or absence. The fields were described either as disturbed, degraded (worst-case) or maturing (best-case). Meloidogyne hapla was present in 3 mineral (2, 8 and 13) and 6 muck (4, 5, 6, 10, 14 15) agricultural fields with degraded and/or disturbed soil conditions and absent from maturing soils, partially supporting the hypothesis.Degraded soils had low nitrogen content in both soil groups. The second objective was to isolate and culture the 9 M. hapla populations to test a hypothesis that PV is related to specific SFW conditions. I found three categories of reproductive potential: the highest (Pop 13), medium (Pop 8), both from degraded mineral soils, and lowest from disturbed mineral (Pop 2) and disturbed (Pops 4, 6 and 10) and degraded (Pops 5, 14 and 15) muck soils. Thus, the hypothesis was not supported. The third objective, was to determine relationships between microbial community structure and M. hapla distribution. My working hypotheses were that there is a relationship among microbiome, soil health and M. hapla occurrence. Microbial community structure in the fields was determined from sub-samples of the same samples where the nematodes were isolated. I used 16S (bacteria) and ITS (fungi) rDNA analysis and characterized the microbial composition, core- and indicator-microbes co-existing with M. hapla pop in the field soils and soil conditions relative to the Ferris SFW model description. The results showed that bacterial and fungal community abundance and composition varied by soil group, SFW conditions and/or M. hapla occurrence. I found that a core of 39 bacterial and 44 fungal sub-operational taxonomic units (OTUs) were found variably, 25 bacterial OTUs associated with presence or absence of M. hapla, and 1,065 OTUs were associated SFW conditions. All three hypotheses were supported. The final objective was to determine the relationship between PV and the microbes associated with M. hapla pop. I compared bacteria present in M. hapla pop isolated from the field and greenhouse cultures. The hypothesis was that either presence and/or absence of specific bacteria are associated with M. hapla population. Population 8 shared more bacteria with the lowest reproductive potential pop than Population 13. Presence of several bacteria was unique to Population 8 as was the absence of other bacteria to Pop 13 in either field or greenhouse nematodes. Therefore, the hypothesis was supported. My research findings provide a foundation for: a) testing the relationship between M. hapla PV and the BPC conditions and b) designing soil health-based management strategies.
Author: Isaac Lartey Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 0
Book Description
Managing Meloidogyne hapla remains challenging due to the ban of broad-spectrum nematicides, lack of resistant crops and its broad host range. It also has parasitic variability (PV) where populations (pop) are morphologically and genetically similar but vary in pathogenicity and reproductive potential. Although PV in M. hapla appears to have some relationship to soil types, what soil conditions favor its PV and/or its distribution are unknown. The goal of my research was to understand the soil conditions where M. hapla PVexist by quantifying the biophysicochemical (BPC) conditions from the ecosystem down to microbiome level. I designed observational and experimental approaches and tested four objectives. First, was to evaluate the association between soil conditions and M. hapla distribution at the ecosystem level. My hypothesis was that the presence of M. hapla will be associated with degraded soil conditions. I selected 15 (6 muck and 9 mineral soil)agricultural fields with adjacent natural vegetation in southwest, northwest and eastern regions of the lower peninsula of Michigan as study sites. I collected a total of 75 (5 per field)georeferenced soil samples from agricultural fields and equal number from adjacent natural vegetation soils, quantified the soil food web (SFW) conditions using the Ferris SFW model, and screened for M. hapla presence or absence. The fields were described either as disturbed, degraded (worst-case) or maturing (best-case). Meloidogyne hapla was present in 3 mineral (2, 8 and 13) and 6 muck (4, 5, 6, 10, 14 15) agricultural fields with degraded and/or disturbed soil conditions and absent from maturing soils, partially supporting the hypothesis.Degraded soils had low nitrogen content in both soil groups. The second objective was to isolate and culture the 9 M. hapla populations to test a hypothesis that PV is related to specific SFW conditions. I found three categories of reproductive potential: the highest (Pop 13), medium (Pop 8), both from degraded mineral soils, and lowest from disturbed mineral (Pop 2) and disturbed (Pops 4, 6 and 10) and degraded (Pops 5, 14 and 15) muck soils. Thus, the hypothesis was not supported. The third objective, was to determine relationships between microbial community structure and M. hapla distribution. My working hypotheses were that there is a relationship among microbiome, soil health and M. hapla occurrence. Microbial community structure in the fields was determined from sub-samples of the same samples where the nematodes were isolated. I used 16S (bacteria) and ITS (fungi) rDNA analysis and characterized the microbial composition, core- and indicator-microbes co-existing with M. hapla pop in the field soils and soil conditions relative to the Ferris SFW model description. The results showed that bacterial and fungal community abundance and composition varied by soil group, SFW conditions and/or M. hapla occurrence. I found that a core of 39 bacterial and 44 fungal sub-operational taxonomic units (OTUs) were found variably, 25 bacterial OTUs associated with presence or absence of M. hapla, and 1,065 OTUs were associated SFW conditions. All three hypotheses were supported. The final objective was to determine the relationship between PV and the microbes associated with M. hapla pop. I compared bacteria present in M. hapla pop isolated from the field and greenhouse cultures. The hypothesis was that either presence and/or absence of specific bacteria are associated with M. hapla population. Population 8 shared more bacteria with the lowest reproductive potential pop than Population 13. Presence of several bacteria was unique to Population 8 as was the absence of other bacteria to Pop 13 in either field or greenhouse nematodes. Therefore, the hypothesis was supported. My research findings provide a foundation for: a) testing the relationship between M. hapla PV and the BPC conditions and b) designing soil health-based management strategies.
Author: Sergei A. Subbotin Publisher: Springer ISBN: 331999588X Category : Science Languages : en Pages : 458
Book Description
Plant-parasitic nematodes are recognized as one of the greatest threats to crop production throughout the world. Estimated annual crop losses of $8 billion in the United States and $78 billion worldwide are attributed to plant parasitic nematodes. Plant parasitic nematodes not only cause damage individually but form disease-complexes with other microorganisms thereby increasing crop loss. Nematode diseases of crops are difficult to control because of their insidious nature and lack of specific diagnostic symptoms which closely resemble those caused by other plant pathogens and abiotic diseases. Future developments of sustainable management systems for preventing major economical agricultural losses due to nematodes is focused on strategies that limit production costs, enhance crop yields, and protect the environment. This book presents a first compendium and overview for nematode problems and their management across North America. Each chapter provides essential information on the occurrence and distribution of plant parasitic nematodes, their major crop hosts, impact on crop production and sustainable management strategies for each region of the continent including, Canada, Mexico and all states of the USA. For each region, a thematic overview of changes in crop production affected by plant parasitic nematodes and their management strategies over time will provide invaluable information on the important role of plant parasitic nematodes in sustainable agriculture.
Author: M. Wajid Khan Publisher: Springer Science & Business Media ISBN: 9401114889 Category : Technology & Engineering Languages : en Pages : 388
Book Description
Nematode interactions are important biological phenomena and of great significance in agriculture. It is a fascinating subject which is multidisciplinary by nature, and concerns any scientist involved with plant health. There have been marked advances in our knowledge of various aspects of the subject in the last two decades. This study area has been the subject of several reviews, but there was no exclusive text on the subject. This has stressed the need to document the information, developing a unifying theme which treated nematode interactions in a holistic manner. This book is about the inter action of plant-parasitic nematodes with other plant pathogens or root symbionts, the nature of their associations, their impact on the host and con sequential interactive effects on the involved organisms. Since nematodes are at the centre of the theme, the responsibility of understanding of other plant pathogens dealt with in this book is largely delegated to the reader. I have limited the book content to interactions with biotic pathogens and root symbionts only, for various reasons. The book embodies 16 chapters, and attempts to present balanced infor mation on various aspects of nematode interactions with other plant pathogens and root symbionts. Some chapters describe general aspects of the subject. Interactions of nematodes with specific groups of organisms are addressed in the remaining chapters.
Author: F. Lamberti Publisher: Springer Science & Business Media ISBN: 1475790805 Category : Science Languages : en Pages : 303
Book Description
Plant parasitic nematodes are a main pest to crops. For ex am pie, the root-knot nematodes belonging to the genus Meloidogyne are worldwide in their distribution and attack almost every type of crop, causing considerable losses of yield and affecting quality of produce. The cyst nematodes within the genera Globodera and Heterodera constitute a major group of plant pathogens in many countries throughout the world, suppressing yields of potato, sugar beet, soybean and cereals. Several nematodes such as longidorids and trichodorids are implicated in the transmission of numerous plant viruses. Many others cause constraints to agricultural production either locally or on large areas. However, despite their economic importance (they account for worldwide crop reduction in excess of 10%), plant parasitic nematodes are still poorly understood, because most of them are obligate parasites of roots. Environmental concerns over the agricultural use of pesticides demand the development of alternative measures to control them. To achieve environmentally sound control, knowledge of the basic biology of nematodes must be expanded. Important research areas include understanding the molecular bases for pathogenicity, the molecular mechanisms of the host parasite interactions and the genetic bases for population fluctuations. The workshop has, for the first time, brought together an international group of researchers using molecular approaches to study plant parasitic nematodes and their host responses.
Author: Amanda D. Howland Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 0
Book Description
The United States floriculture industry was valued at $6.43 billion in 2021, with Michigan being the third largest producer, producing 10% of all ornamental plants in the United States. A major constraint to the production of bare-rooted ornamental plants grown in the field are plant-parasitic nematodes. In Michigan, plant-parasitic nematodes cause millions of dollars in economic loss each year in the state's $104.7 billion agriculture industry. In the northern United States and Canada, the northern root-knot nematode, Meloidogyne hapla, is the most economically important perennial ornamental pathogen. While this is a known major pathogen of daylily production, one of top commodities in ornamental plant production in Michigan, very little is known about its impact in daylily production fields or how to effectively manage this pest. There are only two main management strategies for M. hapla in ornamental plant fields: hot water dips and preplant fumigation, both of which do not control M. hapla the entire production cycle and are therefore only semi-effective. Therefore, research was conducted to determine alternative management strategies to manage M. hapla in daylily production fields, with the goal to prevent yield loss and exportation rejection, and reduce the economic burden of this pest. Three multi-year field trials at a commercial nursery in Zeeland, MI, and several greenhouse experiments at Michigan State University's Plant Greenhouses, East Lansing, MI, were conducted to test several different management options and combination of management options to find the best new management strategies to control M. hapla in ornamental plant fields. The results of these studies demonstrate that there are more effective solutions for M. hapla management in ornamental plant field production compared to current practices and highlight three new management options: Indemnify as a soil drench, Majestene 304, and TerraClean 5.0 have been shown to provide the best M. hapla management in daylily fields, with a reduction in M. hapla population levels by 39.5%, 34.7%, and 28.8%, respectively, compared to the control. Indemnify also reduced the number of galled roots by 80% compared to the control plants, which is considerable and can lead to less fields being quarantined and fewer shipment rejections, significantly increasing the profits of the ornamental plant industry. The Indemnify treatment was additionally shown to have a significant positive effect on plant growth, producing plants with some of the largest overall plant biomass, such as plant heights, shoot weights, crown widths, and, most importantly, yield. Plants where Indemnify was applied as a soil drench always had higher yields (on average 41.3% higher) compared to the control plants and higher yields (on average 40% higher) compared to Telone II fumigation. These experiments also show that the annual application of treatments throughout the production cycle is crucial and provides significantly better M. hapla management compared to current practices, which only focuses on managing nematodes at the beginning of the production cycle. Most importantly, these trials show that there was no impact on plant growth, health, and yield from annual treatment applications. Even though M. hapla is well established in these monoculture, long-term ornamental plant fields, a trial determining possible soil suppression showed that natural suppression may not be occurring in ornamental plant fields in Michigan, but more experiments are needed. Two greenhouse trials tested the damage potential and host status of Hemerocallis spp. to M. hapla and Paratylenchus spp., and determined the threshold level of M. hapla. These greenhouse experiments show that daylily is an excellent host to M. hapla, with a threshold level as low as 13 M. hapla/100 cm3 soil. The data also suggests that even though M. hapla affects plant growth, daylily plants may actually be tolerant to M. hapla; over the length of the daylily growth cycle, the plants became more tolerant of its feeding and grew to similar sizes of the nematode-free plants. Lastly, daylily was shown to not be a host to Paratylenchus spp., and therefore, these nematodes do not need to be included in management decisions. Through the application of the new alternative and more sustainable management strategies described in this dissertation, M. hapla can be effectively and efficiently managed in ornamental plant fields leading to a significant advancement in the floriculture industry in Michigan, the northern United States, and Canada.
Author: Don C. Norton Publisher: John Wiley & Sons ISBN: Category : Science Languages : en Pages : 296
Book Description
Aspects of geographical distribution; Dissemination; Habitants; Communities; Population change; The soil environment; Physical and chemical parameters; Survival; Parasitism of nematodes in biological control; Biological interactions; Effects of agricultural practices on nematode populations.
Author: Isaac Lartey
Author: Isaac Lartey
Author: William Morton Powell
Author: Nathaniel Aaron Mitkowski
Author: Sergei A. Subbotin
Author: M. Wajid Khan
Author: F. Lamberti
Author: D. L. Coyne
Author: Amanda D. Howland
Author: Franco Lamberti
Author: Don C. Norton