Humus bacteria of Norway spruce stands: plant growth promoting properties and birch, red fescue and alder colonizing capacity

Abstract

We studied the potential of the humus layer of the Norway spruce stands to supply beneficial rhizobacteria to birch (Betula pendula), alder (Alnus incana) and fescue grass (Festuca rubra), representatives of pioneer vegetation after clear-cutting of the coniferous forest. Axenically grown seedlings of these species were inoculated with the acid spruce humus, pH 3.7^5.3. Actinorhizal propagules, capable of nodulating alder, were present in high density (10 3 g 31 ) in humus of long-term limed plots, whereas plots with nitrogen fertilization contained almost none (910 g 31 ). The genera most frequently found in the humus were Bacillus, Paenibacillus, Arthrobacter, Nocardia, Rhodococcus and Pseudomonas, independently of prior liming or fertilization of the plots. The taxa found in the seedling roots differed from that in humus by the prevalence of the Gram-negative genera Pseudomonas, Alcaligenes and Comamonas. Enrichment cultures of the roots on nitrogen-free media yielded Paenibacillus and Rhodococcus species. Nitrogen-fixing R. erythropolis and a novel Paenibacillus, closest by full sequence of 16S rDNA to P. durus, represented new classes of nitrogen-fixing rhizosphere bacteria. In addition, nitrogen-fixing R. fascians was found in the humus. The rhizoflora and humus contained high proportions of bacteria antagonistic towards plant pathogenic Rhizoctonia sp., Botrytis cinerea and Fusarium culmorum. The antagonistic isolates also commonly produced siderophores and/or cell wall degrading enzymes. ß

Application of spent Agaricus subrufescens compost in integrated production of seedlings and plants of tomato

“…In addition to fertility and plant nutrition, SMC that is produced using the appropriate technology also has the advantage of containing a rich microbiota that can ensure the necessary balance to guarantee the phytosanitary requirements of plant cultures (Elo et al 2000;Viji et al 2003). It is also possible that some species of microorganisms have the potential to induce resistance in seedlings pre-grown on this substrate.…”

Psychrotolerant Paenibacillus tundrae Isolates from Barley Grains Produce New Cereulide-Like Depsipeptides (Paenilide and Homopaenilide) That Are Highly Toxic to Mammalian Cells

“…Paenibacilli utilize starch and other plant-related carbohydrates and also proteins such as gelatin (40) and milk (10). They grow at chilled temperatures of Ͻ10°C (21,30), which explains why they appear frequently in harvested vegetables and grains (19), chilled foods (8,21,23,31), natural wood, as well as humus (18,34). Secondary metabolites of paenibacilli have been investigated for antimicrobial properties with the aim to improve the microbiological safety of foods with extended shelf lives (22,26,47,64,66,67).…”

Comparative genome analysis reveals genetic adaptation to versatile environmental conditions and importance of biofilm lifestyle in Comamonas testosteroni

“…At low iron levels, siderophores are secreted by bacteria to scavenge iron ions from natural environments (Neilands 1995). Previous studies showed that several Comamonas strains isolated from agricultural soil and root surfaces were capable of producing siderophores (Das et al 2014;Elo et al 2000). However, no significant siderophore production could be observed for C. testosteroni (Mampel et al 2004;Patel et al 2007) although genetic analysis identified one inner membrane transport system for siderophores in the genome of C. testosteroni CNB-1 ).…”