作者：Mahmoud, Lamiaa M., Stanton, Daniel, Amin, Basma H., Grosser, Jude W. and Dutt, Manjul
摘要：The Non-Expresser of Pathogenesis-Related Genes 1 (NPR1) is a principal regulator of plant responses to biotic and abiotic stresses. In this study, the response of 'Hamlin' (Citrus sinensis L.) sweet orange clones overexpressing the Arabidopsis thaliana NPR1 (AtNPR1; AT1G64280) were investigated under salt stress. Selected transgenic and non-transgenic lines were clonally propagated onto US-942 rootstock ('Sunki' (Citrus reticulata) x 'Flying Dragon' (Poncirus trifoliata)). One-year-old budded plants were irrigated three times per week with 0, 100, or 200 mM sodium chloride (NaCl) solution. Our results showed low sensitivity in response to 200 mM NaCl in AtNPR1 transgenic plants compared to non transgenic (WT) control plants. The malondialdehyde (MDA) content significantly decreased in response to NaCl levels in the WT plants when compared with the transgenic line. Likewise, the scavenging activity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical significantly decreased in the WT control. However the DPPH activity in the AtNPR1 transgenic plants did not vary significantly even under increased salt stress. The transcript levels of the antioxidants CsSOD1, CsGST, CsCAT and CsAPX1, as well as the sodium transporters CsSOS3 and CsNHX1, were significantly increased in the AtNPR1 transgenic plants under salt stress conditions compared to the WT plants. The ultrastructural analysis of leaf mesophyll cells in wild type control plants showed high accumulation of starch granules in the chloroplasts under increased salt stress (200 mM NaCl); however, this was not observed in the AtNPR1 transgenic plants. These findings suggest that the NPR1 signaling pathway is associated with photosynthesis improvement, ROS scavengers, and cell membrane integrity: main mechanisms that are involved in salt and oxidative stress tolerance in citrus. Accordingly, our findings suggest that NPR1 has a protective role following salt stress and can be a potential candidate gene for improving the abiotic stress tolerance of citrus. Key message The Arabidopsis derived AtNPR1 overexpression confer enhanced salt tolerance in transgenic citrus plants.
文献注录：Mahmoud, Lamiaa M., Stanton, Daniel, Amin, Basma H., Grosser, Jude W. and Dutt, Manjul. Overexpression of the Arabidopsis NPR1 gene confers enhanced salt tolerance by regulating antioxidant and starch accumulation in citrus [J]. . 2022, 3.
报/刊名：《》，发表于2022 / 第 3 期。
文献类型： [J]
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