Combined de novo transcriptomic and physiological analyses reveal RyALS3-mediated aluminum tolerance in Rhododendron yunnanense Franch

Abstract

Rhododendron (Ericaceae) not only has ornamental value, but also has great medicinal and edible values. Many Rhododendron species are native to acid soils where aluminum (Al) toxicity limits plant productivity and species distribution. However, it remains unknown how Rhododendron adapts to acid soils. Here, we investigated the physiological and molecular mechanisms of Al tolerance in Rhododendron yunnanense Franch. We found that the shoots of R. yunnanense Franch did not accumulate Al after exposure of seedlings to 50 μM Al for 7 days but predominantly accumulated in roots, suggesting that root Al immobilization contributes to its high Al tolerance. Whole-genome de novo transcriptome analysis was carried out for R. yunnanense Franch root apex in response to 6 h of 50 μM Al stress. A total of 443,639 unigenes were identified, among which 1,354 and 3,413 were up- and down-regulated, respectively, by 6 h of 50 μM Al treatment. Both Gene Ontology (GO) enrichment and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses revealed that genes involved in “ribosome” and “cytoskeleton” are overrepresented. Additionally, we identified Al-tolerance homologous genes including a tonoplast-localized ABC transporter RyALS3; 1. Overexpression of RyALS3; 1 in tobacco plants confers transgenic plants higher Al tolerance. However, root Al content was not different between wild-type plants and transgenic plants, suggesting that RyALS3; 1 is responsible for Al compartmentalization within vacuoles. Taken together, integrative transcriptome, physiological, and molecular analyses revealed that high Al tolerance in R. yunnanense Franch is associated with ALS3; 1-mediated Al immobilization in roots.

Strigolactones alleviate AlCl3 stress by vacuolar compartmentalization and cell wall blocking in apple

“…Al 3+ can be compartmentalized into vacuoles to reduce cytoplasmic Al 3+ content through a mechanism mainly controlled by the ABC transporter ALS. RyALS3 is located on the vacuole membrane in Rhododendron yunnanense and mediates Al partitioning into the vacuole (Xu, Lei, et al., 2022). AtALS1 is also located in the tonoplast and is responsible for transporting Al from the cytoplasm to vacuoles under Al toxicity (Larsen et al., 2007).…”

“…ALS3 participates in the Al tolerance mechanism of plants through interaction with cinnamyl alcohol deaminase (CAD) (Wu et al., 2019). RyALS3 also transports Al from the cytoplasm into vacuoles and mediates the fixation of Al in roots, thereby improving Al tolerance of plants (Xu, Lei, et al., 2022). Previous studies have also shown that sensitive to proton rhizotoxicity (STOP), the core transcription factor responding to AlCl 3 stress enhances compartmentalization of Al in vacuoles by regulating the expression of ALS3 .…”

A Genome-Wide Analysis and Expression Profile of Heat Shock Transcription Factor (Hsf) Gene Family in Rhododendron simsii

“…Each product was ligated into the binary vector (pCAMBIA1300-35S::GFP) to produce a Pro35S::RsHsf::GFP construct, which was then transformed into Agrobacterium tumefaciens strain EHA105. The transformed A. tumefaciens was used to infiltrate the leaves of 4-week-old tobacco plants [58]. At 48-72 h after infiltration, GFP signals were observed using Nikon Eclipse Ni-U microscope (Nikon, Tokyo, Japan).…”

Differences in gas exchange, chlorophyll fluorescence, and modulated reflection of light at 820 nm between two rhododendron cultivars under aluminum stress conditions

“…In China, rhododendrons are mainly distributed in the southwestern region, in which soil acidification is severe [ 38 ]. Rhododendrons can grow well in acidic soil with high Al concentrations, implying they may have evolved complex mechanisms that enable them to effectively cope with Al stress [ 39 ]. Due to the different genetic backgrounds, the morphology, traditional use, phytochemistry and pharmacology of different varieties of rhododendrons are very different, which may lead to the great differences in their physiology and biochemistry [ 40 ].…”