Overexpression of the Brassica rapa bZIP Transcription Factor, BrbZIP-S, Increases the Stress Tolerance in Nicotiana benthamiana
Department of Industrial Plant Science and Technology, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 28644, Republic of Korea
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Authors to whom correspondence should be addressed.
Biology 2023, 12(4), 517; https://doi.org/10.3390/biology12040517
Submission received: 28 February 2023
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Revised: 21 March 2023
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Accepted: 27 March 2023
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Published: 29 March 2023
(This article belongs to the Collection Abiotic Stress in Plants and Resilience: Recent Advances)
Simple Summary
Energy homeostasis plays a crucial role in regulating plant defense responses. In this study, we characterized BrbZIP-S (S1-bZIP from Brassica rapa) as a key modulator of energy metabolism, including sugar and proline metabolism. In addition, plants overexpressing BrbZIP-S exhibited increased tolerance to darkness and heat stress, suggesting that BrbZIP-S regulates plant stress responses through a complex network mediated by abscisic acid, sugar, and proline.
Abstract
In higher plants, S1-basic region-leucine zipper (S1-bZIP) transcription factors fulfill crucial roles in the physiological homeostasis of carbon and amino acid metabolisms and stress responses. However, very little is known about the physiological role of S1-bZIP in cruciferous vegetables. Here, we analyzed the physiological function of S1-bZIP from Brassica rapa (BrbZIP-S) in modulating proline and sugar metabolism. Overexpression of BrbZIP-S in Nicotiana benthamiana resulted in delayed chlorophyll degradation during the response to dark conditions. Under heat stress or recovery conditions, the transgenic lines exhibited a lower accumulation of H2O2, malondialdehyde, and protein carbonyls compared to the levels in transgenic control plants. These results strongly indicate that BrbZIP-S regulates plant tolerance against dark and heat stress. We propose that BrbZIP-S is a modulator of proline and sugar metabolism, which are required for energy homeostasis in response to environmental stress conditions.
