Global leaf and root transcriptome in response to cadmium reveals tolerance mechanisms in Arundo donax L

Abstract

The expected increase of sustainable energy demand has shifted the attention towards bioenergy crops. Due to their know tolerance against abiotic stress and relatively low nutritional requirements, they have been proposed as election crops to be cultivated in marginal lands without disturbing the part of lands employed for agricultural purposes. Arundo donax L. is a promising bioenergy crop whose behaviour under water and salt stress has been recently studied at transcriptomic levels. As the anthropogenic activities produced in the last years a worrying increase of cadmium contamination worldwide, the aim of our work was to decipher the global transcriptomic response of A. donax leaf and root in the perspective of its cultivation in contaminated soil. In our study, RNA-seq libraries yielded a total of 416 million clean reads and 10.4 Gb per sample. De novo assembly of clean reads resulted in 378,521 transcripts and 126,668 unigenes with N50 length of 1812 bp and 1555 bp, respectively. Differential gene expression analysis revealed 5,303 deregulated transcripts (3,206 up- and 2,097 down regulated) specifically observed in the Cd-treated roots compared to Cd-treated leaves. Among them, we identified genes related to “Protein biosynthesis”, “Phytohormone action”, “Nutrient uptake”, “Cell wall organisation”, “Polyamine metabolism”, “Reactive oxygen species metabolism” and “Ion membrane transport”. Globally, our results indicate that ethylene biosynthesis and the downstream signal cascade are strongly induced by cadmium stress. In accordance to ethylene role in the interaction with the ROS generation and scavenging machinery, the transcription of several genes (NADPH oxidase 1, superoxide dismutase, ascorbate peroxidase, different glutathione S-transferases and catalase) devoted to cope the oxidative stress is strongly activated. Several small signal peptides belonging to ROTUNDIFOLIA, CLAVATA3, and C-TERMINALLY ENCODED PEPTIDE 1 (CEP) are also among the up-regulated genes in Cd-treated roots functioning as messenger molecules from root to shoot in order to communicate the stressful status to the upper part of the plants. Finally, the main finding of our work is that genes involved in cell wall remodelling and lignification are decisively up-regulated in giant reed roots. This probably represents a mechanism to avoid cadmium uptake which strongly supports the possibility to cultivate giant cane in contaminated soils in the perspective to reserve agricultural soil for food and feed crops.

Physiological and Productive Responses of Two Vitis vinifera L. Cultivars across Three Sites in Central-South Italy

“…Our results were strengthened by the evidence of the different canopy expansions observed at each site and the morphological architecture of the leaves of the studied cultivars [23,57]. It was observed that a vine with a smaller canopy would use less water than one with a larger canopy, affecting grapevine water use [58][59][60]. Cabernet Sauvignon generally showed a higher compact canopy throughout Molise, Campania, and Sicily (in this site, the training system also contributed to reducing the canopy expansion) and smallest leaves (mainly for laterals) together with the surface that, at maturity, is highly sclerotic compared to the Aglianico leaves.…”

Cadmium Phytotoxicity on Seed Germination, Early Growth and the Differential Antioxidant Response of Guaiacol Peroxidase in <i>Phragmites australis</i> Seedling Organs

“…The enzymatic antioxidant defense response differs between plant species, stage of development, organ, and duration of exposure, as well as between various stress conditions and their frequencies [67,15]. In the present study, the leaf/root GpOx activity ratio was >1 in control and [73,74,75]. According to Barceló et al (2004) [68], lignification may negatively affect root elongation by reducing cell wall extensibility, which minimizes nutrient uptake and plant growth.…”

Transcriptomic, cytological, and physiological analyses reveal the potential regulatory mechanism in Tartary buckwheat under cadmium stress

“…As reported by Lux et al (2011), the physical barriers like Casparian strip and lignification can limit Cd translocation to the shoots. Santoro et al (2022) believed that the up-regulated gene involved in cell wall remodeling and lignification had the function of avoiding cadmium uptake. It's probably another way for Tartary buckwheat to respond to Cd stress (El Rasafi et al, 2020).…”

“…The cell wall is the first barrier for Cd to get into the cell and the major site to immobilize Cd by ion binding, which is an important strategy to detoxify Cd in plants ( Shanmugaraj et al., 2019 ; Santoro et al., 2022 ). The GMGT1 gene (Gene ID: FtPinG0100416000.01 ) is involved in galactomannan biosynthesis ( Edwards et al., 2004 ).…”