MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China; Department of Agroecology, Faculty of Technical Sciences, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark.
MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
Sci Total Environ. 2020 Jul 15;726:138554. doi: 10.1016/j.scitotenv.2020.138554. Epub 2020 Apr 8.
Plant growth-promoting bacteria (PGPB) can promote photosynthesis and biomass production of hyperaccumulators, achieving enhanced phytoremediation efficiency of cadmium (Cd). A better understanding of the mechanisms controlling photosynthesis of hyperaccumulating plants by PGPB is necessary for developing strategies that promote the practical phytoextraction of Cd-polluted soils. In this study, chlorophyll fluorescence, gas exchange, and transcriptome sequencing were conducted to evaluate the physiological and transcriptional changes on photosynthesis and carbon fixation in hyperaccumulator Sedum alfredii after inoculation with PGPB Pseudomonas fluorescens. The results showed that bacterial inoculation significantly enhanced maximum quantum yield of PS II (Fv/Fm), effective quantum yield of PS II (ΦPSII), photochemical quenching (qP) and chlorophyll concentration, while reduced non-photochemical quenching (NPQ) of S. alfredii. Further, inoculation resulted in an increased net photosynthetic rates (Pn), intercellular CO concentration (Ci), transpiration rate (Tr) and stomatal conductance (Gs) of the studied plant. At the transcriptional level, 70 photosynthetic genes and 42 C4-pathway carbon fixation related genes were significantly up-regulated in response to inoculation, which could be the reason for enhanced photosynthesis and dry biomass. To sum up, this P. fluorescens strain can simultaneously promote growth and Cd uptake of S. alfredii, which can be a promising bacterial agent applied to Cd phytoremediation practices.
植物促生菌（PGPB）可以促进超积累植物的光合作用和生物量生产，从而提高镉（Cd）的植物修复效率。为了开发促进 Cd 污染土壤实际植物提取的策略，有必要更好地了解 PGPB 控制超积累植物光合作用的机制。在这项研究中，通过接种植物促生菌荧光假单胞菌，进行叶绿素荧光、气体交换和转录组测序，以评估超积累植物垂盆草光合作用和碳固定的生理和转录变化。结果表明，细菌接种显著提高了 PSII 的最大量子产量（Fv/Fm）、PSII 的有效量子产量（ΦPSII）、光化学猝灭（qP）和叶绿素浓度，同时降低了垂盆草的非光化学猝灭（NPQ）。此外，接种还导致研究植物的净光合速率（Pn）、胞间 CO 浓度（Ci）、蒸腾速率（Tr）和气孔导度（Gs）增加。在转录水平上，70 个光合作用基因和 42 个 C4 途径碳固定相关基因对接种有显著上调反应，这可能是光合作用和干生物量增强的原因。总之，这种荧光假单胞菌菌株可以同时促进垂盆草的生长和 Cd 吸收，这可能是一种有前途的细菌剂，可应用于 Cd 植物修复实践。
