Performance of Actinobacteria isolated from rhizosphere soils on plant growth promotion under cadmium toxicity

Abstract

This work aimed to evaluate the potential use of plant growth-promoting actinobacteria (PGPA) for enhanced cadmium (Cd) phytoremediation and plant growth. Forty-two actinobacteria were isolated from rhizosphere soils in Thailand. Among isolates tested, only Streptomyces phaeogriseichromatogenes isolate COS4, showed the high ability to produce siderophores as a plant growth stimulant and had a strong Cd tolerance potential. The significance of siderophores production and Cd tolerance ability under different Cd concentrations suggests the potential of isolate COS4 to work effectively. Plant culture revealed that the significant increase in root length, root to tip length, and total dried weight of sunflower were obtained after 2 h incubation of sunflower seeds with isolate COS4. The efficiency of Cd uptake was found to range between 42.3 and 61.3%. Translocation factor results confirmed that plant growth promoting S. phaeogriseichromatogenes isolate COS4-assisted phytoremediation can be considered as Cd absorbents for the restoration of polluted sites due to high translocation values.

Graphical Abstract

Novelty statement To the best of our knowledge, this is the first report on the use of Streptomyces phaeogriseichromatogenes for cadmium (Cd) phytoremediation and sunflower growth promotion potentials. More than 42% of Cd was effectively removed using Cd tolerant plant growth promoting S. phaeogriseichromatogenes isolate COS4-assisted phytoremediation. These data indicated that S. phaeogriseichromatogenes isolate COS4 and sunflower could be considered as high-efficient heavy metal accumulator in accordance with world standards for promoting environmentally sustainable agriculture.

Keywords:

• Actinobacteria
• cadmium
• plant growth promotion
• remediation
• siderophore
• Streptomyces
• sunflower

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was supported by CMU Mid-Career Research Fellowship program from Chiang Mai University, Thailand.