scholarly journals Morphological, molecular and ecological characterization of a native isolate of Steinernema feltiae (Rhabditida: Steinernematidae) from southern Chile

2020 ◽  
Author(s):  
Patricia A Flores ◽  
Andrea Alvarado ◽  
Gabriela Lankin ◽  
Paola Lax ◽  
Simona Prodan ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Geographical Area ◽  
Nuclear Genes ◽  
Steinernema Feltiae ◽  
Rrna Gene ◽  
Chilean Isolate

Abstract Background: Steinernema feltiae is an entomopathogenic nematode used in biological control programs with a global distribution. Populations of this species show phenotypic plasticity derived from local adaptation, and vary in different traits, such as location and host penetration. The aim of this work was to describe a Chilean isolate of this nematode species, using integrative approaches.Methods: Nematode morphological and morphometric studies were conducted along with molecular analysis of nuclear genes. The symbiotic bacterium was also identified by sequencing the 16S rRNA gene. Some ecological characteristics were described, including the temperature requirements for nematode life cycle and the effect of soil water content for optimal reproduction. Results: Morphometric characterization revealed a large intra-specific variability. The isolate identity was also corroborated with the analysis of nuclear genes. Based on the 16S gene, its symbiont bacteria, Xenorhabdus bovienii, was identified. The lowest, optimal and highest temperatures found to limit the infestation and reproduction on Galleria mellonella were 10, 20 and 30 °C respectively; the emergence from the host larvae occurred approximately ten days after inoculation. Differences were observed in offspring, and 120 infective juveniles (IJ)/larva was the most prolific dose at 20 °C. The soil water content did not affect the number of IJ invaders, penetration efficacy and IJ emergence time or offspring per larva, but it caused a delay in achieving full mortality at the permanent wilting point with respect to saturation and field capacity.Conclusions: For the first time, a Chilean isolate of S. feltiae is described in detail considering morphological, molecular and ecological aspects. The isolate showed to be efficient in soil containing water, with optimal temperatures ranging from 15 to 25 °C for host infestation and production of an abundant offspring; these characteristics would allow its potential use as control agents in a wide geographical area of the country

scholarly journals Morphological, molecular and ecological characterization of a native isolate of Steinernema feltiae (Rhabditida: Steinernematidae) from southern Chile

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Patricia Flores ◽  
Andrea Alvarado ◽  
Gabriela Lankin ◽  
Paola Lax ◽  
Simona Prodan ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Geographical Area ◽  
Nuclear Genes ◽  
Steinernema Feltiae ◽  
Rrna Gene ◽  
Chilean Isolate

Abstract Background Steinernema feltiae is an entomopathogenic nematode used in biological control programs with a global distribution. Populations of this species show phenotypic plasticity derived from local adaptation and vary in different traits, such as location and host penetration. The aim of this work was to describe a Chilean isolate of this nematode species, using integrative approaches. Methods Nematode morphological and morphometric studies were conducted along with molecular analysis of nuclear genes. The symbiotic bacterium was also identified by sequencing the 16S rRNA gene. Some ecological characteristics were described, including the temperature requirements for the nematode life cycle and the effect of soil water content for optimal reproduction. Results Morphometric characterization revealed a large intra-specific variability. The isolate identity was also corroborated with the analysis of nuclear genes. Based on the 16S gene, its symbiont bacteria, Xenorhabdus bovienii, was identified. The lowest, optimal and highest temperatures found to limit the infestation and reproduction on Galleria mellonella were 10, 20 and 30 °C, respectively; the emergence from the host larvae occurred approximately 10 days after inoculation. Differences were observed in offspring, and 120 infective juveniles (IJ)/larva was the most prolific dose at 20 °C. The soil water content did not affect the number of IJ invaders, penetration efficacy and IJ emergence time or offspring per larva, but it caused a delay in achieving full mortality at the permanent wilting point with respect to saturation and field capacity. Conclusions For the first time, a Chilean isolate of S. feltiae is described in detail considering morphological, molecular and ecological aspects. The isolate was shown to be efficient in soil containing water, with optimal temperatures ranging from 15 to 25 °C for host infestation and production of an abundant offspring; these characteristics would allow its potential use as control agents in a wide geographical area of the country.

scholarly journals Detection of Soil Water Content Using Continuous Wave Ground Penetrating Radar

2018 ◽  
Vol 2 (1) ◽  
pp. 44 ◽  
Author(s):  
Sonal Oimbe ◽  
Rahul Ingle ◽  
Raval Awale
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Ground Penetrating Radar ◽  
Continuous Wave ◽  
Geographical Area ◽  
Time Signal ◽  
Data Sets ◽  
Ground Penetrating ◽  
Mumbai City

In this work, continuous wave ground-penetrating radar (CW-GPR) has been used for detecting the soil water content in context to farm management. It is here speculated that CW-GPR utilized to observe variations in Soil parameters in different geographical area where traditional methods fails such as reflection-based GPR method. An experiment was performed on different farms in and around Mumbai city locality in a 20 * 14 m section of natural grassland at the SAMEER- IIT BOMBAY Research Facility in Mumbai city, INDIA. Two survey methods such as velocity analysis and GPR reflection surveys of ground wave were inefficient at the experiment site due to the signal attenuation which is related with the clay-rich soil. CW-GPR data sets were collected on regular and daily basis during a 5-d period in February 2017. The samples of soil were collected for analysis purpose from the mentioned geographical area. The clear response has been observed for early time signal amplitude to changes in soil water content using CW-GPR data. The strong correlation has been observed between the GPR data sets with Soil water content, which is uniform with the CW-GPR dependence on relative permittivity. The outcome reveals that the CW-GPR method can be utilized to acquire spatially distributed information on subsurface moisture content in clay-rich soils.

Identification and ecological characterisation of three entomopathogenic nematode-bacterium complexes from Turkey

Nematology ◽  
2001 ◽  
Vol 3 (8) ◽  
pp. 833-841 ◽  
Author(s):  
Alper Susurluk ◽  
Urs Wyss ◽  
Ralf-Udo Ehlers ◽  
Olaf Strauch ◽  
Erko Stackebrandt ◽  
...  
Keyword(s):  
Water Content ◽  
Galleria Mellonella ◽  
Entomopathogenic Nematode ◽  
Its Region ◽  
Steinernema Feltiae ◽  
Bacterial Symbionts ◽  
Hybrid Strain ◽  
Cross Breeding ◽  
Length Analysis ◽  
The University

AbstractTwo heterorhabditid nematode strains (TUR-H1 and TUR-H2), and their bacterial symbionts isolated from soil samples taken at the campus of the Agriculture Faculty of the University of Ankara, Turkey, were identified by molecular methods and by cross-breeding with Heterorhabditis bacteriophora. The bacterial symbionts shared >99% similarity in the 16S rDNA sequence with Photorhabdus luminescens subsp. laumondii. Results of the restriction fragment length analysis of the ITS region assigned both nematode strains to the species H. bacteriophora. Cross-breeding confirmed the species designation for strain TUR-H2. Crosses of TUR-H1 with a hybrid strain of H. bacteriophora or with TUR-H2 resulted in infertile offspring. Both strains reproduced in monoxenic cultures of the symbionts P.luminescens isolated from H. bacteriophora and H. megidis and the resulting dauer juveniles retained cells of the bacteria. Reproduction on the symbionts isolated from H. indica failed. Infectivity at variable soil moisture and heat tolerance of the two heterorhabditid strains was compared with a Turkish isolate of Steinernema feltiae. Significantly more nematodes invaded the insect Galleria mellonella in a sandy soil assay at 10% water content than at lower values. A higher water content significantly reduced the invasion rate. Steinernema feltiae was better adapted to a temperature of 32°C than the heterorhabditid strains. Hardly any nematodes of all strains survived for longer than 4 h at 36°C.

SOIL WATER CONTENT AFFECTS THE AVAILABILITY OF PHOSPHATE

1985 ◽  
pp. 185-189
Author(s):  
M.C.H.Mouat Pieter Nes
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Solution ◽  
Equivalent Reduction

Reduction in water content of a soil increased the concentration of ammonium and nitrate in solution, but had no effect on the concentration of phosphate. The corresponding reduction in the quantity of phosphate in solution caused an equivalent reduction in the response of ryegrass to applied phosphate. Keywords: soil solution, soil water content, phosphate, ryegrass, nutrition.

Effect of inter-row cultivation on soil carbon dioxide emission in a peach plantation

2010 ◽  
Vol 59 (1) ◽  
pp. 157-164 ◽  
Author(s):  
E. Tóth ◽  
Cs. Farkas
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Carbon Dioxide Emission ◽  
Nutrient Content ◽  
Soil Disturbance ◽  
Biological Properties ◽  
Soil Tillage ◽  
Favourable Effect ◽  
Volumetric Soil Water Content

Soil biological properties and CO2emission were compared in undisturbed grass and regularly disked rows of a peach plantation. Higher nutrient content and biological activity were found in the undisturbed, grass-covered rows. Significantly higher CO2fluxes were measured in this treatment at almost all the measurement times, in all the soil water content ranges, except the one in which the volumetric soil water content was higher than 45%. The obtained results indicated that in addition to the favourable effect of soil tillage on soil aeration, regular soil disturbance reduces soil microbial activity and soil CO2emission.

Evaluation of a Multi-Rod Probe Performance for Accurate Measurements of Soil Water Content

2020 ◽  
Author(s):  
Justyna Szerement ◽  
Aleksandra Woszczyk ◽  
Agnieszka Szyplowska ◽  
Marcin Kafarski ◽  
Arkadiusz Lewandowski ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content

Effects of soil water content and temperature on Bt protein degradation in leaves at thinning stage and buds of Bt cotton

2014 ◽  
Vol 22 (3) ◽  
pp. 300-307
Author(s):  
Meijun ZHANG ◽  
Wude YANG ◽  
Meichen FENG ◽  
Yun DUAN ◽  
Mingming TANG ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Bt Cotton ◽  
Bt Protein

Evapotranspiration Measurement and Irrigation Scheduling for Several Tropical Fruit Crops Using the EnviroScan System

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 549f-550
Author(s):  
Mongi Zekri ◽  
Bruce Schaffer ◽  
Stephen K. O'Hair ◽  
Roberto Nunez-Elisea ◽  
Jonathan H. Crane
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Use ◽  
National Parks ◽  
Quantitative Information ◽  
Irrigation Scheduling ◽  
Management Tool ◽  
Fruit Crops ◽  
Tropical Fruit

In southern Florida, most tropical fruit crops between Biscayne and Everglades National Parks are irrigated at rates and frequencies based on experience and observations of tree growth and fruit yield rather than on reliable quantitative information of actual water use. This approach suggests that irrigation rates may be excessive and could lead to leaching of agricultural chemicals into the groundwater in this environmentally sensitive area. Therefore, a study is being conducted to increase water use efficiency and optimize irrigation by accurately scheduling irrigation using a very effective management tool (EnviroScan, Sentek Environmental Innovations, Pty., Kent, Australia) that continuously monitors soil water content with highly accurate capacitance multi-sensor probes installed at several depths within the soil profile. The system measures crop water use by monitoring soil water depletion rates and allows the maintenance of soil water content within the optimum range (below field capacity and well above the onset of plant water stress). The study is being conducted in growers' orchards with three tropical fruit crops (avocado, carambola, and `Tahiti' lime) to facilitate rapid adoption and utilization of research results.

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