Draft Genome Sequence of Phosphate-Solubilizing Bacterium Paraburkholderia tropica Strain P-31 Isolated from Pomegranate (Punica granatum) Rhizosphere.

We report the 8.9 Mb draft genome sequence of phosphate-solubilizing bacterium Paraburkholderia tropica strain P-31, isolated from pomegranate (Punica granatum) rhizosphere. The draft genome sequence of Paraburkholderia tropica strain P-31 consists of 8,881,246 bp with a G+C content of 64.7%, 8,039 protein-coding genes, and 49 RNAs.

Citricoccus zhacaiensis B-4 (MTCC 12119) a novel osmotolerant plant growth promoting actinobacterium enhances onion (Allium cepa L.) seed germination under osmotic stress conditions.

The water potential of rhizospheric soil is a key parameter that determines the availability of water, oxygen, and nutrients to plants and microbes. Recent global warming trends and erratic precipitation patterns have resulted in the emergence of drought as a major constraint of agricultural productivity. Though several strategies are being evaluated to address this issue, a novel approach is the utilization of microbes for alleviation of drought stress effects in crops. Citricoccus zhacaiensis B-4 is an osmotolerant actinobacterium isolated from banana rhizosphere on mannitol supplemented medium (-2.92 MPa osmotic potential). This isolate expressed plant growth promotion traits viz, IAA, GA3 production, phosphate, zinc solubilization, ACC deaminase activity and ammonia production under PEG induced osmotic stress and non-stress conditions. Under in vitro osmotic conditions, biopriming with the actinobacterium improved the percent germination, seedling vigour and germination rate of onion seeds (cv. Arka Kalyan) at osmotic potentials up to -0.8 MPa. Considering its novelty, osmotolerance and plant growth promoting traits, biopriming with C. zhacaiensis is suggested as a viable option for the promotion of onion seed germination under drought stressed environments.

Alleviation of cold stress in inoculated wheat (Triticum aestivum L.) seedlings with psychrotolerant Pseudomonads from NW Himalayas.

Twelve psychrotolerant Pseudomonad strains were selected on the basis of various plant growth-promoting (PGP) activities at cold temperature (4°C). The effect of inoculation with Pseudomonad strains on cold alleviation and growth of wheat seedling at cold temperature (8°C) was investigated under greenhouse condition. Inoculation with Pseudomonad strains significantly enhanced root/shoot biomass and nutrients uptake as compared to non-bacterized control at 60 days of plant growth. Bacterization significantly improved the level of cellular metabolites like chlorophyll, anthocyanin, free proline, total phenolics, starch content, physiologically available iron, proteins, and amino acids that are sign of alleviation of cold stress in wheat plants. Increased relative water content, reduced membrane injury (electrolyte leakage), and Na(+)/K(+) ratio were also recorded in bacterized wheat plants. Electrolyte leakage and Na(+)/K(+) were found inversely proportional to plant growth at cold temperature. Statistical analysis of twenty-three measured parameters revealed that uninoculated control was under cold stress while eight bacterial strains were positively alleviating cold stress in wheat plants. Thus, the psychrotrophic Pseudomonad strains could effectively provide a promising solution to overcome cold stress, which is major factor hindering wheat productivity under cold climatic condition.

Mountain aspect influences the genetic clustering of psychrotolerant phosphate solubilizing Pseudomonads in the Uttarakhand Himalayas.

Fourteen cold tolerant phosphate solubilizing bacteria isolated from high altitude representative locations of the two major mountain aspects of the Uttarakhand Himalayas (cooler north and warmer south facing slopes) were selected for this study. The tricalcium phosphate (TCP) solubilizing abilities of the isolates were estimated at three different incubation temperatures viz., 4, 15, and 30 degrees C under in vitro conditions. Irrespective of their geographical origin, all the isolates recorded maximum P release values at 30 degrees C. At 4 degrees C, the isolates from the north facing slope were found to release significantly higher levels of P, as compared to the isolates from the south facing slopes. Alternatively at 15 degrees C, the isolates from the south facing slope were found to release significantly higher levels of P. Initial confirmation of their genus level identity as Pseudomonads was arrived by amplification of a 990 bp fragment of the 16S rRNA gene using genus specific primers. Further putative species level identification was arrived by sequencing of the 16S rRNA gene. The diversity among the isolates was determined by rep-PCR using the primers BOX, ERIC, and ERIC2. A composite dendrogram constructed using the rep-PCR profiles revealed that the isolates from the north and south mountain aspects formed separate major clusters. The extent of diversity was greater among the isolates from the south mountain aspect. This study reveals the potential of rep-PCR in determining the genetic diversity among Pseudomonads selected for a single functional trait, but varying in their geographical origin.

Differential toxicity of Bacillus thuringiensis strains and their crystal toxins against high-altitude Himalayan populations of diamondback moth, Plutella xylostella L.

BACKGROUND: Diamondback moth, Plutella xylostella (L.), is a major insect pest of crucifers in the biodiversity-rich north-western Indian Himalayan hills. The present investigation was aimed at determining the susceptibility pattern of P. xylostella populations collected from different locations of this region to autochthonous and standard Bacillus thuringiensis strains. RESULTS: Among the reference as well as indigenous B. thuringiensis strains tested, sub spp. kurstaki HD-1, kurstaki HD-73, galleriae HD-8, local galleriae/colmeri strain BtOa1 and some of their Cry1 class toxins were found to be highly toxic. Surprisingly, the sub sp. tolworthi HD-125, local tolworthi strain BtHa1 and Cry9 class toxins were found to be non-toxic. Midgut homogenate from fourth-instar larvae was found to activate 130 kDa protoxin from the local tolworthi strain BtHa1 into 68 kDa toxin, but failed to exert any larval mortality, probably owing to lack of receptor binding. CONCLUSION: The present study provides valuable baseline susceptibility data for the deployment of B. thuringiensis-based control methods, as well as for future monitoring of development of resistance in P. xylostella to B. thuringiensis in this ecologically sensitive region.