Effects of pesticides on plant growth promoting traits of Mesorhizobium strain MRC4
By M. Ahemad, M. S. Khan. 2012
113 citations recorded by the source corpus.
Abstract The objective of this study was to assess the effect of selected pesticides [herbicides (metribuzin and glyphosate), insecticides (imidacloprid and thiamethoxam) and fungicides (hexaconazole, metalaxyl and kitazin)] at recommended and higher dose rates on plant growth promoting activities of the Mesorhizobium sp. isolated from chickpea-nodules. A total of 50 rhizobial strains recovered from the nodules of chickpea root systems were identified following morphological, biochemical and host-specificity tests and tested for pesticide-tolerance. Among these strains, the Mesorhizobium sp. strain MRC4 was specifically selected due to the highest tolerance levels for all selected pesticides and the maximum production of plant growth promoting substances. Strain MRC4 produced indole acetic acid (44 μg ml −1 ), siderophores [salicylic acid (35 μg ml −1 ) and 2,3-dihydroxy benzoic acid (19 μg ml −1 )], exo-polysaccharides (21 μg ml −1 ), HCN and ammonia. Under pesticide-stress, pesticide-concentration dependent progressive-decline in all plant growth promoting traits of the Mesorhizobium sp. strain MRC4 exposed was observed except for exo-polysaccharides which consistently increased with exceeding the concentration of each pesticide from recommended dose. For instance, hexaconazole at three times the recommended dose elicited the maximum stress on siderophore-biosynthesis by the Mesorhizobium sp. strain MRC4 and decreased salicylic acid and DHBA by 40% and 47%, respectively and the greatest stimulatory effect on exo-polysaccharides secretion was shown by imidacloprid which stimulated the Mesorhizobium sp. strain MRC4 to secrete EPS by 38%, compared to control. Generally, the maximum toxicity to plant growth promoting traits of Mesorhizobium was shown by glyphosate, thiamethoxam and hexaconazole, at three times the recommended rate among herbicides, insecticides and fungicides, respectively. This study revealed an additional aspect of the toxicological mechanisms of the pesticides through which they suppress the plant growth.
Subfields: Plant Science
View Paper: https://www.semanticscholar.org/paper/a55a735a21823c23f4be841fc290439044ec3715
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Citations in the corpus
- Remediation of metalliferous soils through the heavy metal resistant plant growth promoting bacteria: Paradigms and prospects (2014, background): “Furthermore, numerous bacteria exhibit efflux trans- porters (e.g. ATPase pumps or chemiosmotic ion/proton pumps) with high substrate affinity by which they expel high concentration of toxic metals outside the cell (Haferburg and Kothe, 2007; Ahemad, 2012).”
- Mechanisms and applications of plant growth promoting rhizobacteria: Current perspective (2014, background): “…2008; Russo et al., 2008; Joo et al., 2005; Murphy et al., 2000) along with the normal plant growth promoting properties such as, phytohor-mone (Ahemad and Khan, 2012c Tank and Saraf, 2010), siderophore (Jahanian et al., 2012; Tian et al., 2009), 1-amino-cyclopropane-1-carboxylate, hydrogen…”
- A review on plant growth promoting rhizobacteria acting as bioinoculants and their biological approach towards the production of sustainable agriculture (2015, background): “…as (a) symbiotic N2 fixing bacteria including members of the family rhizobiaceae which forms symbiosis with leguminous plants (e.g. rhizobia) (Ahemad and Khan, 2012) and non-leguminous trees (e.g. Frankia) and (b) non-symbiotic (free living, associative and endophytes) nitrogen fixing forms…”