Pseudomonas stutzeri improves the tolerance of Lemna minor to Cu(OH)2 nanopesticide by regulating the uptake of copper, antioxidant defense mechanisms, and the expression of metacaspase-1, chlorophyllase, and stress-responsive genes

• Published in: Plant physiology and biochemistry 2023-10, Vol.203, p.108002-108002, Article 108002
• Main Authors: Gulmez, Ozlem, Aksakal, Ozkan, Baris, Ozlem, Bayram, Emrah
• Format: Article
• Language: English
• Subjects: Antioxidant system; Chlorophyllase; Cu(OH)2 nanopesticide; Lemna minor; Metacaspase-1; Pseudomonas stutzeri
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2023.108002

This study investigated the effect of Pseudomonas stutzeri inoculation on Lemna minor treated with Cu(OH)2 nanopesticide (NP). The results showed that P. stutzeri inoculation increased the relative growth rate (RGR) in NP-treated plants. Although chlorophyll and carotenoid contents decreased significantly in NP-treated plants, P. stutzeri inoculation led to an increase in chlorophyll and carotenoid contents in NP-treated plants. Copper (Cu) content increased with increasing NP concentration, but it decreased significantly in the presence of P. stutzeri. NP treatment caused increased H2O2 and TBARS levels, as well as proline levels. However, P. stutzeri inoculation led to decreased H2O2 and TBARS levels and increased SOD, POX, GST, GR, GPX, and DHAR activities. The expression of genes encoding SOD, GST, metacaspase-1, and chlorophyllase was upregulated by NP treatment alone. Additionally, when plants were inoculated with P. stutzeri, the expression of these genes was further enhanced. In conclusion, P. stutzeri inoculation had a positive effect on the growth and antioxidant system of L. minor treated with NP as it enhanced RGR, increased chlorophyll and carotenoid contents, and decreased Cu content and oxidative stress. These findings suggested that P. stutzeri has the potential to promote aquatic plant growth and counteract the negative impacts of NP on these plants. •Cu(OH)2 NP treatment negatively affected photosynthetic pigments, caused lipid peroxidation, and decreased growth in L. minor.•Under Cu(OH)2 NP stress, Pseudomonas stutzeri inoculation reduced Cu content, H2O2 and TBARS levels, enhanced antioxidant enzyme activities in L. minor.•Inoculation of P. stutzeri under Cu(OH)2 NP stress alleviated oxidative stress by up-regulating the expression of genes related to antioxidant system.•Under Cu(OH)2 NP stress, P. stutzeri inoculation reduced NP-induced cytotoxicity by down-regulating the expression of metacaspase-1 and chlorophyllase genes.