Paenibacillus dendritiformis UJA2219 isolated from carrot produces broad-spectrum antibacterial activity. The aim of the present study was to determine the impact of partially-purified cell-culture extracts of strain UJA2219 on the microbial load and bacterial diversity of a home-made vegetable puree. The puree was challenged with an overnight culture of strain UJA2219 or with cultured broth extracts partially purified by cation exchange (CE) chromatog-raphy or reversed-phase (RP) chromatography and incubated for 7 days at temperatures of 4 °C or 25 °C. Best results were obtained at 25 °C with the RP extract, decreasing counts of presump-tive Enterobacteriaceae below detectable levels. The bacterial diversity of control and treated puree was studied by Illumina paired-end sequencing using DNA extracted from the puree samples incubated at 25 °C for 24 h. The controls and the puree inoculated with the UJA2219 strain showed an almost-identical bacterial diversity profile, with Proteobacteria (mainly Fam. Pseudo-monadaceae -gen. Pseudomonas- and Enterobacteriace as most abundant groups). Greatest differences in bacterial diversity were obtained in the puree treated with RP extract, showing a decrease in the relative abundance of Proteobacteria (especially gen. Pseudomonas) and an increase of Firmicutes (mainly of the genera Bacillus, Enterococcus and Lactococcus). Results from the study suggest that the antimicrobial preparations from strain UJA2219 have a potential for application in food bio-preservation.

The application of quantitative PCR (qPCR) as a routine method to detect and enumerate Paenibacillus larvae in honey and hive debris could greatly speed up the estimation of prevalence and outbreak risk of the American foulbrood (AFB) disease of Apis mellifera. However, none of the qPCR tests described so far has been officially proposed as a standard procedure for P. larvae detection and enumeration for surveillance purposes. Therefore, in this study inclusivity, exclusivity and sensitivity in detection of P. larvae spores directly in samples of honey and hive debris were re-evaluated for the previously published qPCR methods. To this aim recently acquired P. larvae sequence data were considered to assess inclusivity in silico and more appropriate non-target species were used to verify exclusivity experimentally. This led to the modification of one of the previously described methods resulting in a new test capable to allow the detection of P. larvae spores in honey and hive debris down to 1 CFU/g. The application of the qPCR test optimized in this study can allow to reliably detect and quantify P. larvae in honey and hive debris, thus circumventing the disadvantages of late AFB diagnosis based on clinical symptoms and possible underestimation of spore numbers that is the main drawback of culture-dependent procedures.

The loose and porous structure and abundant pores of biochar provide conditions for being a suitable fertilizer carrier. Biochar loaded with beneficial microorganisms will greatly promote plant growth and soil improvement. In this work, an environmentally friendly Paenibacillus mucilaginosus loaded biochar-based fertilizer (B@PM) with high nutrient content, good slow-release effect and increased biological activity was prepared. The released mechanism of P-K-Ca from B@PM and the synergistic effect on the soil nutrients and plant growth were also analyzed. The experimental results showed that the release behavior of P, K and Ca from B@PM was diffusive and dissolved, which conforms to the Power function and Parabolic diffusion models, respectively. The potting experiment showed that the root length (30.77%), leaf width (71.67%), and plant height (81.08%) of Chinese cabbage were enhanced after the application of B@PM, and the organic matter, available phosphorus, available potassium, and total calcium in the soil were also substantially enhanced. In addition, the abundance of the Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes in the in the rhizosphere soil was increased, as well as the activities of catalase (82.84%) and alkaline phosphatase (39.64%). The results of RDA analyses showed that B@PM increased the content of the environmental factors, such as OM, URE, EC, TCa, AK, CAT, AP and ALP, thus improving soil quality and plant length.

Paenibacillus sp. tmac-D7 was isolated from coastline growing Trifolium macraei (double-head clover) root nodules from Bodega Bay, California. The draft genome is 5,567,337 bp with a G+C% of 52.4%, an N50 of 114,261 bp, and 5,282 predicted protein-coding genes. Paenibacillus, while found in many other environments, is frequently isolated from root nodules, with many acting as plant pathogen antagonists. Paenibacillus sp. tmac-D7 is the first genome of a non-rhizobial endophyte isolate from wild Trifolium macraei (double-head clover).