Evaluation of rhizosphere Streptomyces for zinc solubilizing and plant growth promoting properties

2021 ◽  
pp. 36-47
Author(s):  
K. Balakrishnan ◽  
Manikkam Radhakrishnan ◽  
Venugopal Gopikrishnan ◽  
J. Thirumalairaj ◽  
Ramasamy Balagurunathan

Actinobacteria were isolated from rhizosphere soil and its plant growth-promoting ability was tested. Actinobacteria were screened for promoting plant growth by phosphate and zinc solubilization, gibberellin, siderophore, HCN and indole-3-acetic acid production. The abiotic stresses of all the isolates were tested for parameters such as pH, temperature and NaCl. Upon screening, a potent actinobacteria named Streptomyces sp. ZS-18 was isolated and identified based on the colony characteristics. The potent strain solubilized both the zinc oxide (26 ± 0.75mm) and zinc carbonate (22 ± 0.88mm). The utilization of gibberellic acid (80μg/ml) by the potential strain ZS-18 showed maximum production measured by optical density value of 0.179. The growth of the green gram plant was determined by shoot, root, total length, number of leaves and chlorophyll estimation of the leaves. Streptomyces sp. ZS-18 showed good growth on ISP 1, ISP 2, ISP 3, ISP 5 and ISP 7 medium and moderate growth was observed in ISP 4 and ISP 6 medium. In addition, Actinobacteria were tested for antagonistic activity against plant pathogens. The isolate ZS-18 in the pot trial experiment showed increased growth in comparison with control and cow dung manure.

Author(s):  
Cun Yu ◽  
Ying Yao

Endophytic fungi were isolated from Phoebe bournei and their diversity and antimicrobial and plant growth-promoting activities were investigated. Of the 389 isolated endophytic fungi, 88.90% belonged to phylum Ascomycota and 11.10% to phylum Basidiomycota. The isolates were grouped into four taxonomic classes, 11 orders, 30 genera, and 45 species based on internal transcribed spacer sequencing and morphologic analysis. The host showed a strong affinity for the genera Diaporthe and Phyllosticta. The diversity of the fungi was highest in autumn, followed by spring and summer, and was lowest in winter. The fungi exhibited notable tissue specificity in P. bournei, and the species richness and diversity were highest in the root across all seasons. Five isolates showed antimicrobial activity against eight plant pathogens, and reduced the incidence of leaf spot disease in P. bournei. Additionally, 9 biocontrol isolates showed plant growth-promoting activity, with five significantly promoting P. bournei seedling growth. This is the first report on the endophytic fungi of P. bournei and their potential applicability to plant disease control and growth promotion.


2005 ◽  
Vol 82 (3) ◽  
pp. 85-102 ◽  
Author(s):  
C.L. Doumbou ◽  
M.K. Hamby Salove ◽  
D.L. Crawford ◽  
C. Beaulieu

Actinomycetes represent a high proportion of the soil microbial biomass and have the capacity to produce a wide variety of antibiotics and of extracellular enzymes. Several strains of actinomycetes have been found to protect plants against plant diseases. This review focuses on the potential of actinomycetes as (a) source of agroactive compounds, (b) plant growth promoting organisms, and (c) biocontrol tools of plant diseases. This review also addresses examples of biological control of fungal and bacterial plant pathogens by actinomycetes species which have already reached the market or are likely to be exploited commercially within the next few years.


PLoS ONE ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. e0194665 ◽  
Author(s):  
Alfonso Méndez-Bravo ◽  
Elvis Marian Cortazar-Murillo ◽  
Edgar Guevara-Avendaño ◽  
Oscar Ceballos-Luna ◽  
Benjamín Rodríguez-Haas ◽  
...  

2020 ◽  
Vol 35 (1-2) ◽  
Author(s):  
Tabish Akhtar ◽  
Shubham Kumar ◽  
Sukhdeo Kumar ◽  
M. R. Meena

The growth of plants promoting rhizobacteria (PGPR) has gained widespread importance in agriculture. These are beneficial bacteria found in nature that live actively in plant roots and improve plant growth and increase agricultural productivity.. (PGPR) promoting plant growth shows an important role in the sustainable agricultural industry. The increasing demand for crop production is a major challenge nowadays, with a significant lack of use of synthetic chemical fertilizers and pesticides. The use of PGPR has proven to be an environmentally sound way of increasing crop yields by facilitating plant growth through direct or indirect mechanisms. The mechanisms of PGPR include regulating hormonal and nutritional balance, inducing resistance against plant pathogens, and dissolving nutrients for easy uptake by plants. Furthermore, PGPRs show synergistic and antagonistic interactions with microorganisms within the rhizosphere and in bulk soils, which indirectly increases plant growth rates. There are several bacteria species that act as PGPR. This review summarizes the methodology of PGPR as a bio-fertilizer in agriculture.


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