Insights from the draft genome of Paenibacillus lentimorbus NRRL B-30488, a promising plant growth promoting bacterium

Detection of spore forming Paenibacillus macerans in raw milk

Paenibacillus macerans can cause spoilage of milk during extended storage. However, the natural milk microbiota interferes with the enumeration of Paenibacillus species in raw milk. In this study, a qualitative SYBR Green real-time PCR assay based on the groEL gene was developed for detecting P. macerans (PMassay) in raw milk and compared with one designed for total Paenibacillus detection (TPassay). The specificity of the PMassay was confirmed against a panel of dairy-related spore forming isolates. In the presence of background DNA substituted up to 95%, P. macerans DNA could still be detected by the PMassay although interference occurred as non-target DNA substitution increased. The PMassay was sensitive (detection limit of 2 log CFU/ml in milk) and specific as non-P. macerans isolates gave a Ct > 30. After enrichment of raw milk for 7 days at 37 °C in Reinforced Clostridial Medium with D-cycloserine (RCM-D) under anaerobiosis, Paenibacillus was detected in 10 of the 16 raw milk samples tested. Enrichment in RCM-D yielded about 0.5 to 5.8 log CFU/ml total Paenibacillus and 0.3 to 4.6 log CFU/ml P. macerans in the samples. The assay could be useful in commercial settings, allowing a sensitive detection of P. macerans.

A multifaceted rhizobacterium Paenibacillus lentimorbus alleviates nutrient deficiency-induced stress in Cicer arietinum L

Nutrient deficiency in soil is one of the limiting factors responsible for stunted growth and poor flowering/fruiting of crops which result in decline in overall agricultural productivity. However, one important strategy to overcome the problem of nutrient deficiency and to avoid use of chemical fertilizers is the use of plant growth promoting rhizobacteria (PGPR). Paenibacillus lentimorbus NRRL B-30488 (hereafter B-30488), an efficient PGPR has been reported to have various plant growth promoting traits that help crops to mitigate various environmental stresses. Therefore, the present work was designed to examine the application of B-30488 on chickpea growth under nutrient stress condition. Plants inoculated with B-30488 showed positive modulation in physio-biochemical behaviour and mineral nutrient uptake for better growth and development. Alteration in gene expression and metabolic profile under nutrient stress condition in chickpea also supported the stress amelioration capability of B-30488. Principal component analysis statistically proved that improved growth performance of chickpea plants under nutrient stress was mainly due to B-30488 induced modulation of metabolic pathways. To the best of our knowledge, this is the first study for analysis of growth promotion and stress alleviation in chickpea plants subjected to nutrient stress in presence of PGPR B-30488.