Limits...
Concilience in Entomopathogenic Nematode Responses to Water Potential and Their Geospatial Patterns in Florida.

El-Borai F, Killiny N, Duncan LW - Front Microbiol (2016)

Bottom Line: When rehydrated after 24 h on filter paper at 90% RH, 50% of Sd survived compared to no Sx.Two isolates of Sd also survived better than two isolates of Sx during up to 24 h in a hypertonic solution (30% glycerol).Similarly, these particular behavioral traits are likely to be useful in guiding the selection or engineering of EPN species for use in different ecoregions.

View Article: PubMed Central - PubMed

Affiliation: Citrus Research and Education Center, University of FloridaLake Alfred, FL, USA; Plant Protection Department, Faculty of Agriculture, Zagazig UniversityZagazig, Egypt.

ABSTRACT
The geospatial patterns of four species of native entomopathogenic nematodes in Florida were previously shown to be related to soil properties that affect soil water potential. Here we compared the responses to water potential of third stage, infective juvenile (IJ), Steinernema sp. (Sx), and Steinernema diaprepesi (Sd) in controlled conditions. The two species were selected because they are closely related (Steinernema glaseri-group), but tend to occupy different habitats. In columns of sandy soil with moisture gradients ranging from field capacity (6% w:w) to saturated (18%), Sx migrated toward wetter soil whereas Sd migrated toward drier soil. Survival of two isolates each of Sx and Sd for 7 days in the absence of food was greatest at 18 and 6% soil moisture, respectively. After three cycles of migration through soil to infect insect larvae 10 cm distant, Sd dominated EPN communities when soil columns were maintained at 6% moisture, whereas Sx was dominant in soil maintained at 18% moisture. When rehydrated after 24 h on filter paper at 90% RH, 50% of Sd survived compared to no Sx. Two isolates of Sd also survived better than two isolates of Sx during up to 24 h in a hypertonic solution (30% glycerol). The behavioral responses of both species to water potential and osmotic gradients were consistent with surveys in which Sx was recovered only from flatwoods ecoregions with shallow water tables and poorly drained soils, whereas Sd most frequently inhabited the central ridge ecoregion comprising well-drained soils and deeper water tables. Comparative proteomic analysis revealed differential expression of proteins involved in thermo-sensation (guanylyl cyclase and F13E6-4) and mechano-sensation and movement (paramyosin, Actin 3, LET-99, CCT-2), depending on whether Sd was in soil at 6 or 18% moisture. Proteins involved in metabolism, lectin detoxification, gene regulation, and cell division also differed between the two conditions. Our data suggest the plausibility of modifying soil moisture conditions in flatwoods orchards in ways that favor more desirable (effective) EPN species. Similarly, these particular behavioral traits are likely to be useful in guiding the selection or engineering of EPN species for use in different ecoregions.

No MeSH data available.


Related in: MedlinePlus

Recovery of two isolates each of infective juvenile Steinernema sp. and S. diaprepesi recovered following 7 d of storage in field capacity (6%) or saturated (18%) sand that originated from a citrus orchard. Proportions were calculated as numbers of nematodes recovered from sand at field capacity divided by the total number of nematodes recovered from soil at both soil moistures. Sd = Steinernema diaprepesi, Sx = Steinernema sp.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4814458&req=5

Figure 3: Recovery of two isolates each of infective juvenile Steinernema sp. and S. diaprepesi recovered following 7 d of storage in field capacity (6%) or saturated (18%) sand that originated from a citrus orchard. Proportions were calculated as numbers of nematodes recovered from sand at field capacity divided by the total number of nematodes recovered from soil at both soil moistures. Sd = Steinernema diaprepesi, Sx = Steinernema sp.

Mentions: Two isolates each of Sd and Sx responded consistently to maintenance at 6% or 18% soil moisture (Figure 3). Approximately two-thirds of the total Sd IJs were recovered from the dryer soil and a similar proportion of Sx IJs were recovered from the wetter soil. The proportion recovery of each species from the two soil conditions differed from 50% (P < 0.001) and there were no significant differences in response to moisture between the two isolates of either species.


Concilience in Entomopathogenic Nematode Responses to Water Potential and Their Geospatial Patterns in Florida.

El-Borai F, Killiny N, Duncan LW - Front Microbiol (2016)

Recovery of two isolates each of infective juvenile Steinernema sp. and S. diaprepesi recovered following 7 d of storage in field capacity (6%) or saturated (18%) sand that originated from a citrus orchard. Proportions were calculated as numbers of nematodes recovered from sand at field capacity divided by the total number of nematodes recovered from soil at both soil moistures. Sd = Steinernema diaprepesi, Sx = Steinernema sp.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814458&req=5

Figure 3: Recovery of two isolates each of infective juvenile Steinernema sp. and S. diaprepesi recovered following 7 d of storage in field capacity (6%) or saturated (18%) sand that originated from a citrus orchard. Proportions were calculated as numbers of nematodes recovered from sand at field capacity divided by the total number of nematodes recovered from soil at both soil moistures. Sd = Steinernema diaprepesi, Sx = Steinernema sp.
Mentions: Two isolates each of Sd and Sx responded consistently to maintenance at 6% or 18% soil moisture (Figure 3). Approximately two-thirds of the total Sd IJs were recovered from the dryer soil and a similar proportion of Sx IJs were recovered from the wetter soil. The proportion recovery of each species from the two soil conditions differed from 50% (P < 0.001) and there were no significant differences in response to moisture between the two isolates of either species.

Bottom Line: When rehydrated after 24 h on filter paper at 90% RH, 50% of Sd survived compared to no Sx.Two isolates of Sd also survived better than two isolates of Sx during up to 24 h in a hypertonic solution (30% glycerol).Similarly, these particular behavioral traits are likely to be useful in guiding the selection or engineering of EPN species for use in different ecoregions.

View Article: PubMed Central - PubMed

Affiliation: Citrus Research and Education Center, University of FloridaLake Alfred, FL, USA; Plant Protection Department, Faculty of Agriculture, Zagazig UniversityZagazig, Egypt.

ABSTRACT
The geospatial patterns of four species of native entomopathogenic nematodes in Florida were previously shown to be related to soil properties that affect soil water potential. Here we compared the responses to water potential of third stage, infective juvenile (IJ), Steinernema sp. (Sx), and Steinernema diaprepesi (Sd) in controlled conditions. The two species were selected because they are closely related (Steinernema glaseri-group), but tend to occupy different habitats. In columns of sandy soil with moisture gradients ranging from field capacity (6% w:w) to saturated (18%), Sx migrated toward wetter soil whereas Sd migrated toward drier soil. Survival of two isolates each of Sx and Sd for 7 days in the absence of food was greatest at 18 and 6% soil moisture, respectively. After three cycles of migration through soil to infect insect larvae 10 cm distant, Sd dominated EPN communities when soil columns were maintained at 6% moisture, whereas Sx was dominant in soil maintained at 18% moisture. When rehydrated after 24 h on filter paper at 90% RH, 50% of Sd survived compared to no Sx. Two isolates of Sd also survived better than two isolates of Sx during up to 24 h in a hypertonic solution (30% glycerol). The behavioral responses of both species to water potential and osmotic gradients were consistent with surveys in which Sx was recovered only from flatwoods ecoregions with shallow water tables and poorly drained soils, whereas Sd most frequently inhabited the central ridge ecoregion comprising well-drained soils and deeper water tables. Comparative proteomic analysis revealed differential expression of proteins involved in thermo-sensation (guanylyl cyclase and F13E6-4) and mechano-sensation and movement (paramyosin, Actin 3, LET-99, CCT-2), depending on whether Sd was in soil at 6 or 18% moisture. Proteins involved in metabolism, lectin detoxification, gene regulation, and cell division also differed between the two conditions. Our data suggest the plausibility of modifying soil moisture conditions in flatwoods orchards in ways that favor more desirable (effective) EPN species. Similarly, these particular behavioral traits are likely to be useful in guiding the selection or engineering of EPN species for use in different ecoregions.

No MeSH data available.


Related in: MedlinePlus