Pseudomonas isolates have frequently been isolated from the rhizosphere of plants, and several of them have been reported as plant growth-promoting rhizobacteria. In the present work, tomato (Solanum lycopersicum) seeds were germinated in greenhouse conditions, and the seedling height, length of plants, collar diameter and number of leaves were measured from plants grown in soil inoculated by bacterial isolates. Pseudomonas isolates were isolated from the rhizosphere. We used the Newman-Keuls test to ascertain pairwise differences. Isolates were identified as a new Pseudomonas species by rpoD gene sequencing. The results showed that isolates of Pseudomonas sp. (Q6B) increased seed germination (P = 0.01); Pseudomonas sp. (Q6B, Q14B, Q7B, Q1B and Q13B) also promoted seedling height (P = 0.01). All five isolates promoted plant length and enlarged the collar diameter (P = 0.01). Pseudomonas sp. (Q1B) also increased leaf number (P = 0.01). The investigation found that Pseudomonas isolates were able to solubilize phosphate, produce siderophores, ammonia, and indole-3-acetic acid and colonize the roots of tomato plants. This study shows that these five novel Pseudomonas sp. isolates can be effective new plant growth-promoting rhizobacteria.
As the most abundant animals on earth, nematodes are a dominant component of the soil community. They play critical roles in regulating biogeochemical cycles and vegetation dynamics within and across landscapes and are an indicator of soil biological activity. Here, we present a comprehensive global dataset of soil nematode abundance and functional group composition. This dataset includes 6,825 georeferenced soil samples from all continents and biomes. For geospatial mapping purposes these samples are aggregated into 1,933 unique 1-km pixels, each of which is linked to 73 global environmental covariate data layers. Altogether, this dataset can help to gain insight into the spatial distribution patterns of soil nematode abundance and community composition, and the environmental drivers shaping these patterns.
8 January 2020 in International Journal of Pest Management
Plants are often subject to attack by fungi, nematodes and insects, which generate immense yield losses. Hence, the quest for crop protection solutions is ongoing, concurrent with greater awareness towards the use of synthetic chemicals in agricultural practice. Scientific research has shifted towards the use of natural products, which possess good efficacy and are environment friendly. This review details two classes of natural products. The first one is the plant essential oils with their volatile constituents, which have been proven to possess antifungal, nematicidal and insecticidal activities. The second class is the lipopeptides produced by antagonistic microorganisms. Their biological activities are discussed, as they have been shown effective against plant fungi and pests. Essential oils and lipopeptides have huge potential to be used as biopesticides. The combinatorial approach between essential oils, antagonistic microorganisms and lipopeptides for crop protection is discussed, potentially both can produce a synergistic effect, resulting from their combination against plant fungi, nematodes and pests.