What is it about?

We previously generated Brassica juncea lines overexpressing either glyoxalase I (gly I) or γ-tocopherol methyltransferase (γ-TMT) involved in the glyoxalase system and tocopherol biosynthesis, respectively. These transgenic plants showed tolerance to multiple abiotic stresses. As tolerance is a complex trait that can be improved by pyramiding of several characteristics in a single genotype, we generated in this study B. juncea plants coexpressing gly I and γ-TMT by crossing the previously generated stable transgenic lines. The performance of the newly generated B. juncea lines coexpressing gly I and γ-TMT was compared with that of wild-type and the single transgenic lines under non-stressed and NaCl and mannitol stress conditions. Our results show a more robust antioxidant response of B. juncea plants coexpressing gly I and γ-TMT compared to the other lines in terms of higher chlorophyll retention, relative water content, antioxidant enzyme and proline levels, and photosynthetic efficiency and lower oxidative damage. The differences in response to the stress of the different lines were reflected in their yield parameters. Overall, we demonstrate that the pyramiding of multiple genes involved in antioxidant pathways could be a viable and useful approach for achieving higher abiotic stress tolerance in crop plants.

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Why is it important?

We previously reported the efficacy of overexpressing γ-tocopherol methyl transferase (γ-TMT) (Kumar et al., 2013a; Yusuf et al., 2010) and glyoxylase I (gly I) (Rajwanshi et al., 2016) in conferring abiotic stress tolerance in Brassica juncea (the Indian mustard). This study was conducted to investigate the effects of simultaneous expression of γ-TMT and gly I in B. juncea. Herein, we report the synergistic effects of expressing these genes together on abiotic stress tolerance in B. juncea plants.


We show that the γ-TMT and the gly I genes from different metabolic pathways act in a synergistic manner to modulate the antioxidant machinery for combating NaCl and mannitol stress. Pyramiding of multiple genes involved in ROS detoxification pathway could be a viable and useful approach for achieving higher abiotic stress tolerance in crop plants. Future studies evaluating the performance of homozygous crossbred lines overexpressing γ-TMT and the gly I under containment facilities would further validate the approach.

Dr. Deepak Kumar
Banaras Hindu University

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This page is a summary of: Pyramiding of γ‐TMT and gly I transgenes in Brassica juncea enhances salinity and drought stress tolerance, Physiologia Plantarum, January 2022, Wiley, DOI: 10.1111/ppl.13618.
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