Plant Growth and Drought Tolerance-Promoting Bacterium for Bioremediation of Paraquat Pesticide Residues in Agriculture Soils

Abstract

Thailand is an agricultural country. However, agricultural productivity relies on the heavy use of herbicides, especially paraquat. Paraquat accumulation is emerging as a problem in an ever-growing portion of agricultural land. Paraquat residues are toxic to plants, animals, and aquatic organisms in the environment. Biological remediation is a process that can mitigate agricultural chemical contaminants. One of the interesting bioremediators is bacteria. Not only do certain soil bacteria remediate paraquat, but some of them also possess plant growth-promoting properties, which provide advantages in field application. Thus, this study aimed to screen soil bacteria that could degrade paraquat and, at the same time, promote plant growth. Bacteria were isolated from paraquat-treated agricultural soil in Mueang Kaen Pattana municipality, Chiang Mai province, Thailand. On the basis of morphological and 16S rDNA sequence analyses, the selected bacterium was identified as Bacillus aryabhattai strain MoB09. It is capable of growing in nitrogen-free media. B. aryabhattai growth and paraquat degradation were found to be optimum at pH 7 and 30°C. This selected strain also possessed plant growth-promoting abilities, including indole production, siderophore production, phosphate solubilization, and 1-aminocyclopropane-1-carboxylic acid deaminase activity. Paraquat degradation was also evaluated in pot experiments of cowpea (Vigna unguiculata). It was found that this strain could remediate the paraquat residue in both sterilized and non-sterilized soils. The cowpea plants grown in paraquat-contaminated soil with B. aryabhattai showed longer root and shoot lengths than those grown in soil without bacterial inoculation. In addition, B. aryabhattai also promoted the growth of cowpea under induced drought stress. These results suggested that B. aryabhattai could be applied to mitigate paraquat residue in soil and also to promote plant productivity for the organic crop production.

Characterization of Morganella sp. for its Paraquat Degradation Potential

“…showed that the bacteria can grow best at pH of 6.5 with an optimum temperature of 30 ºC. Similar optimum temperatures and slightly higher pH of 7.0 have been reported on paraquat degradation by Bacillus aryabhattai [27].…”

Tolerance of pesticides and antibiotics among beneficial soil microbes recovered from contaminated rhizosphere of edible crops

“…Contrarily, some chemicals pesticides may induce toxicity to beneficial rhizospheric microorganisms even at extremely low doses ( Shahid et al., 2021d ). Likewise our study, Bacillus aryabhattai strain MoB09, recovered from agricultural soils contaminated with paraquat herbicide, utilized herbicide as carbon source under controlled condition and grew well ( Inthama et al., 2021 ). In addition, a similar study conducted by Aroua et al.…”

El Hologenoma, una herramienta para el estudio de los problemas ambientales ocasionados por xenobióticos.

“…Las bacterias y los hongos son los principales degradadores. Entre los aislados bacterianos destacan Bacillus, Pseudomonas, Flavobacterium, Arthrobacter, Diaphorobacter, Klebsiella, Ochrobactrum, Agrobacterium, Burkholderia, Kocuria, Archromobacter, Sphingomonas, Chromohalobacter, entre otros que han sido reportados como degradadores de plaguicidas (Ataikiru et al, 2020;Inthama et al, 2021). Las condiciones ambientales, en particular la presencia o ausencia de oxígeno tiene una influencia notable en la degradación de plaguicidas (Reineke, 2001).…”