Unlocking the Mysteries of Science
PGPB: Biodiversity and Multifunctional Attributes for Sustainable Agriculture
August 24, 2017
The use of plant growth promoting bacteria may prove useful in developing strategies to facilitate plant growth under normal as well as diverse abiotic stress conditions. The application of microbes with the aim of improving nutrients availability for plants is an important practice and necessary for sustainable agriculture. During the past couple of decades, the use of microbial inoculants for sustainable agriculture has increased tremendously in various parts of the world. Significant increases in growth and yield of agronomically important crops in response to inoculation with plant growth promoting (PGP) microbes have been repeatedly reported. The actual biodiversity of PGP microbes belong to different groups including Actinobacteria, Bacteroidetes, Balneolaeota Firmicutes, Proteobacteria and Spirochaetes. PGP bacteria are naturally occurring soil bacteria that aggressively colonize plant roots and benefit plants by providing growth promotion either directly by solubilization of phosphorus, potassium and zinc; production of indole acetic acids, gibberellic acid, cytokinin; biological nitrogen fixation or in-directly by production of ammonia, hydrogen cyanide, siderophore and biocontrol against different plant pathogens. In this review, we have discussed method of isolation, characterization, identification and biodiversity of bacteria associated with crops and further mechanisms of plant growth promotion under the normal as well as diverse abiotic stress conditions.
Ajar Nath Yadav, Priyanka Verma, Bhanumati Singh, Vinay Singh Chauahan, Archna Suman, Anil Kumar Saxena.
Plant Growth Promoting Bacteria: Biodiversity and Multifunctional Attributes for Sustainable Agriculture. Adv Biotech & Micro. 2017; 5(5): 555671. DOI: 10.19080/
Bacterial Modes of Action for Enhancing of Plant Growth
August 02, 2016
The greatest issue affecting the sustainability of broad acre cropping both environmentally and economically is
the requirement of fertilizers. These are based on mined phosphorous or other mineral ores, ammonia produced
through the Harbour-Bosch process and industrially manufactured potash. As global demand for fertilizers increases,
the costs associated with the production for each of these major nutrients increases. Biofertilizers such as plant
growth promoting bacteria (PGPB) are possible biotechnology that could alleviate the need for the addition of increasing amounts of fertilizers.
Premachandra D1,2, Hudek L1 and Brau L1*
1Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3125, Australia
2Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3125, Australia
Enhanced Iron and Selenium Uptake in Plants by Volatile Emissions of Bacillus amyloliquefaciens (BF06)
January 17, 2017
Abstract: Volatile organic compounds (VOCs) released by plant growth-promoting rhizobacteria
(PGPR) are involved in promoting growth and triggering systemic resistance (ISR) in plants.
Importantly, the release of VOCs by some PGPR strains confers improved plant uptake of nutrient
elements from the soil. However, the underlying mechanisms of VOCs-regulated nutrient acquisition
remain elusive. In this study, VOCs were extracted and identified from Bacillus amyloliquefaciens (strain
BF06) using gas chromatography–mass spectrometry (GC–MS). BF06 VOCs exposure significantly
promoted the growth and photosynthesis of Arabidopsis plants. To explore how microbial VOCs
stimulate growth in plants, gene expression profiles of Arabidopsis seedlings exposed to BF06 VOCs
were examined using transcriptomic analyses. In screening differentially expressed genes (DEGs),
most upregulated DEGs were found to be related to amino acid transport, iron (Fe) uptake and
homeostasis, and sulfate transport. Furthermore, BF06 VOCs significantly enhanced Fe absorption in
plants under Fe-limited conditions. However, when nitric oxide (NO) synthesis was inhibited,
BF06 VOCs exposure could not substantially augment Fe acquisition in plants under alkaline
stress, indicating that VOCs-mediated plant uptake of Fe was required for induction of root NO
accumulation. In addition, BF06 VOCs exposure led to a marked increase in some genes encoding for
sulfate transporters, and further increased Se accumulation in plants. Intriguingly, BF06 VOCs
exposure failed to increase Se uptake in sultr1;2 mutants, which may indicate that high-level
transcription of these sulfate transporters induced by BF06 VOCs was essential for enhancing Se
absorption by plants. Taken together, our results demonstrated the potential of VOCs released by this
strain BF06 to increase Fe and Se uptake in plants.
JianfeiWang 1,*, Cheng Zhou 1,*, Xin Xiao 1, Yue Xie 1, Lin Zhu 2 and Zhongyou Ma 1
1 Key Laboratory of Bio-organic Fertilizer Creation, Ministry of Agriculture,
Anhui Science and Technology University, Bengbu 233100, China; firstname.lastname@example.org (X.X.);
email@example.com (Y.X.); firstname.lastname@example.org (Z.M.)
2 School of Life Science and Technology, Tongji University, Shanghai 200092, China;
* Correspondence: email@example.com (J.W.); firstname.lastname@example.org (C.Z.);
Tel.: +86-550-673-2024 (J.W. & C.Z.)
Rhizobacterial Strain Bacillus megaterium BOFC15 Induces Cellular Polyamine Changes that Improve Plant Growth and Drought Resistance
June 21, 2016
Abstract: Plant-growth-promoting rhizobacteria can improve plant growth, development, and stress adaptation. However, the underlying mechanisms are still largely unclear. We investigated the effects of Bacillus megaterium BOFC15 on Arabidopsis plants. BOFC15 produced and secreted spermidine (Spd), a type of polyamine (PA) that plays an important role in plant growth. Moreover, BOFC15 induced changes in the cellular PAs of plants that promoted an increase of free Spd and spermine levels. However, these effects were remarkably abolished by the addition of dicyclohexylamine (DCHA), a Spd biosynthetic inhibitor. Additionally, the inoculation with BOFC15 remarkably increased plant biomass, improved root system architecture, and augmented photosynthetic capacity. Inoculated plants also displayed stronger ability to tolerate drought stress than non-inoculated (control) plants. Abscisic acid (ABA) content was notably higher in the inoculated plants than in the control plants under drought stress and polyethylene glycol (PEG)-induced stress conditions. However, the BOFC15-induced ABA synthesis was markedly inhibited by DCHA. Thus, microbial Spd participated in the modulation of the ABA levels. The Spd-producing BOFC15 improved plant drought tolerance, which was associated with altered cellular ABA levels and activated adaptive responses.
Cheng Zhou 1,2,†, Zhongyou Ma 2,†, Lin Zhu 1, Xin Xiao 2, Yue Xie 2, Jian Zhu 1,* and Jianfei Wang 2,*
School of Life Science and Technology, Tongji University, Shanghai 200092, China
Key Laboratory of Bio-Organic Fertilizer Creation, Ministry of Agriculture, Anhui Science and Technology University, Bengbu 233100, China
Phosphorus Solubilizing Bacteria: Occurrence, Mechanisms and Their role in Crop Production.
Plants acquire phosphorus from soil solution as phosphate anion. It is the least mobile element in plant and soil contrary to other macronutrients. It precipitates in soil as orthophosphate or is adsorbed by Fe and Al oxides through legend exchange. Phosphorus solubilizing bacteria play role in phosphorus nutrition by enhancing its availability to plants through release from inorganic and organic soil P pools by solubilization and mineralization. Principal mechanism in soil for mineral phosphate solubilization is lowering of soil pH by microbial production of organic acids and mineralization of organic P by acid phosphatases. Use of phosphorus solubilizing bacteria as inoculants increases P uptake. These bacteria also increase prospects of using phosphatic rocks in crop production. Greater efficiency of P solubilizing bacteria has been shown through co-inoculation with other beneficial bacteria and mycorrhiza. This article incorporates the recent developments on microbial P solubilization into classical knowledge on the subject.
Department of Agronomy, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran
Isolation and characterization of drought resistance bacteria for plant growth promoting properties and their effect on chilli (Capsicum annuum) seedling under salt stress
Abstract: The search for efficient drought resistant bacteria from unexplored environments is worldwide to alleviate the negative effects in plant growth. Thus, 67 bacteria were isolated from Commiphora wightii rhizosphere soil collected in the desert region. Initial screening for drought tolerance revealed that 29 (43.0%) isolates were able to grow in the presence of 15 g NaCl (w/v), 40 (58.20%) isolates were shown thermo tolerance capacity up to 70 °C and 32 (47.8%) isolates were shown maximum tolerance for polyethylene glycolconcentration (13 g/100 ml). A subset of 10 strains was identified based on 16 S rRNA genesequencing and belonged to four genera (Bacillus spp, Alcaligenes spp, Proteus sp. and Aneurinibacillus aneurinilyticus). All strains could produce siderophore and showed indole-3-acetic acid production ranged from 120 to 520 µg/ml. The drought resistant bacterized seeds of chilli were evaluated in the pot soil supplemented with 50 mM NaCl, the isolates showed 23.3–114.6% and 44.2–125.9% higher root and shoot lengths, respectively, compared with control. Our results demonstrated that drought resistant bacteria isolated from the rhizosphere of C. wightii grown on desert lands could be used for alleviating salinity stress in crop plants.
C. G. Bhakta Institute of Biotechnology, Uka Tarsadia University, Maliba Campus, Bardoli, Surat 394350, Gujarat, India