PHYTOREMEDIATION OF PARTS CONTAMINATED WITH ISOPROTURONE, TRANSGENIC OILY BEANS

The widespread use of isoproturon [IPU] can lead to severe environmental pollution and threats to environmental functions. In this study, the PDMAB IPU bacterial n-demethylase gene was transported and expressed in fat pea chloroplast [Glycine Max L. 'Zhonghuang13']. Transgenic fat bean pods showed significant resistance to PPU and demethylated PPU to the phytotoxic 3-[4 - isopropylphenyl]-1-methylurea [MDIPU] metabolite in vivo. Transgenic fat bean pods removed 98% and 84% MPU from water and soil in 5 and 14 days respectively, accumulating fewer MPU in plant tissues compared to wild type [WT]. MPs showed higher rates of symbiotic nitrogen fixation in transgenic fat peas under stress [total biomass o f nodules and higher nitrogenase activity] and a more stable community of rhizosphere bacteria than WT. However, intensive use and accumulation of toxic herbicides can negatively affect the symbiosis of legumes. Thirty different herbicides and environmental pollutants have affected signaling between plants and rhizobias, delayed node formation, and reduced biological nitrogen fixation in vitro [Fox et al., 2007]. This study developed a transgenic [TS] oil bean that is capable of effectively removing PPU from the growing environment and restoring the high symbiotic ability to fix nitrogen under PPU stress, and provides new insight into the interaction between rhizospheric microorganisms and legumes under herbicidal stress.

1. Dellacioppa, G., Bauer, S.C., Klein, B.K., Shah, D.M., Fraley, R.T. and Kishore, G.M. [1986] Translocation of the precursor of 5-enolpyruvylshikimate-3-phosphate snthase into chloroplasts of higher plants in vitro. Proc. Natl Acad. Sci. USA, 83, 6873- 6877.Aktar, M.W., Sengupta, D. and Chowdhury, A. [2009] Impact of pesticides use in agriculture: their benefits and hazards. Interdiscip. Toxicol. 2, 1-12.

2. Arpaia, S., Christiaens, O., Giddings, K., Jones, H., Mezzetti, B., Moronta-Barrios, F., Perry, J.N. et al [2020] Biosafety of GM crop plants expressing dsRNA: data requirements and EU regulatory considerations. Front. Plant Sci. 11, 13.

3. Chu, C.W., Liu, B., Liu, J.W., He, J., Lv, L.J., Wang, H.M., Xie, X.T. et al. [2020] Phytoremediation of acetochlor residue by transgenic Arabidopsis expressing the acetochlor N-dealkylase from Sphingomonas wittichii DC-6. Sci. Total Environ. 728, 138687.Baho, D.L., Rizzuto, S., Nizzetto, L., Hessen, D.O., Norberg, J., Skjelbred, B., Jones, K.C. et al. [2021] Ecological memory of historical contamination influences the response of phytoplankton communities. Ecosystems, 24, 1591-1607.

4. Cary, T.J., Rylott, E.L., Zhang, L., Routsong, R.M., Palazzo, A.J., Strand, S.E. and Bruce, N.C. [2021] Field trial demonstrating phytoremediation of the military explosive RDX by XplA/XplB-expressing switchgrass. Nat. Biotechnol. 39, 1216-1219.

5. Chauhan, L.K., Kumar, M., Paul, B.N., Goel, S.K. and Gupta, S.K. [2007] Cytogenetic effects of commercial formulations of deltamethrin and/or isoproturon on human peripheral lymphocytes and mouse bone marrow cells. Environ. Mol. Mutagen. 48, 636-643.

6. Daubech, B., Remigi, P., de Moura, G.D., Marchetti, M., Pouzet, C., Auriac, M.C., Gokhale, C.S. et al. [2017] Spatio-temporal control of mutualism in legumes helps spread symbiotic nitrogen fixation. Elife, 6, e28683.