Pseudomonas fluorescens promote photosynthesis, carbon fixation and cadmium phytoremediation of hyperaccumulator Sedum alfredii

• Published in: The Science of the total environment 2020-07, Vol.726, p.138554-138554, Article 138554
• Main Authors: Wu, Yingjie, Ma, Luyao, Liu, Qizhen, Sikder, Md Maniruzzaman, Vestergård, Mette, Zhou, Kaiyue, Wang, Qiong, Yang, Xiaoe, Feng, Ying
• Format: Article
• Language: English
• Subjects: Carbon fixation; Heavy metal; Photosynthesis; Plant growth-promoting bacteria; Transcriptome
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.138554

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 CO2 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. [Display omitted] •Enhanced Cd phytoremediation can be achieved by PGPB inoculation.•PGPB can promote photosynthesis of S. alfredii by inducing physiological and transcriptional changes.•PGPB can promote CO2 assimilation of S. alfredii by upregulating gene expression of related enzymes.•S. alfredii is a C4 plant, or a potential facultative CAM plant.