Lang Pan, Hongwei Zhao, Qin Yu, Lianyang Bai, Liyao Dong
Abstract
Herbicide resistance can be either target-site or non-target-site based. The molecular mechanisms underlying non-target-site resistance (NTSR) are poorly understood, especially at the level of gene expression regulation. MicroRNAs (miRNAs) represent key post-transcriptional regulators of eukaryotic gene expression and play important roles in stress responses. In this study, the miR397 gene from Beckmannia syzigachne (referred to as bsy-miR397) was functionally characterized to determine its role in regulating fenoxaprop-P-ethyl resistance. We showed that (1) bsy-miR397 transcript level is constitutively higher in resistant than in sensitive B. syzigachne plants, whereas bsy-Laccase expression and activity show the opposite trend, and (2) bsy-miR397 suppresses the expression of bsy-Laccase in tobacco, indicating that it negatively regulates bsy-Laccase at the transcriptional level. We found evidences that miR397/laccase regulation might be involved in fenoxaprop-P-ethyl NTSR. First, the rice transgenic line overexpressing OXmiR397 showed improved fenoxaprop-P-ethyl tolerance. Second, following activation of bsy-Laccase gene expression by CuSO4 treatment, fenoxaprop resistance in B. syzigachne tended to decrease. Therefore, we suggest that bsy-miR397 might play a role in fenoxaprop-P-ethyl NTSR in B. syzigachne by down-regulating laccase expression, potentially leading to the enhanced expression of three oxidases/peroxidases genes to introduce an active moiety into herbicide molecules in Phase-2 metabolism. Bsy-miR397, bsy-Laccase, and other regulatory components might form a regulatory network to detoxify fenoxaprop-P-ethyl in B. syzigachne, supported by the differential expression of transcription factors and oxidases/peroxidases in the rice transgenic line overexpressing OXmiR397. This implies how down-regulation of a gene (laccase) can enhance NTSR. Our findings shed light on the daunting task of understanding and managing complex NTSR in weedy plant species.
This research output has an Altmetric Attention Score of 1. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 08 June 2017.
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#18,554,389
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#13,915
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#238,988
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#465
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