Transcriptome Analysis Reveals Cotton (Gossypium hirsutum) Genes That Are Differentially Expressed in Cadmium Stress Tolerance

Abstract

High concentrations of heavy metals in the soil should be removed for environmental safety. Cadmium (Cd) is a heavy metal that pollutes the soil when its concentration exceeds 3.4 mg/kg. Although the potential use of cotton to remediate heavy Cd-polluted soils is known, little is understood about the molecular mechanisms of Cd tolerance. In this study, transcriptome analysis was used to identify Cd tolerance genes and their potential mechanisms in cotton. We exposed cotton plants to excess Cd and identified 4627 differentially expressed genes (DEGs) in the root, 3022 DEGs in the stem and 3854 DEGs in the leaves through RNA-Seq analysis. Among these genes were heavy metal transporter coding genes (ABC, CDF, HMA, etc.), annexin genes and heat shock genes (HSP), amongst others. Gene ontology (GO) analysis showed that the DEGs were mainly involved in the oxidation–reduction process and metal ion binding. The DEGs were mainly enriched in two pathways, the influenza A and pyruvate pathway. GhHMAD5, a protein containing a heavy-metal binding domain, was identified in the pathway to transport or to detoxify heavy metal ions. We constructed a GhHMAD5 overexpression system in Arabidopsis thaliana that showed longer roots compared to control plants. GhHMAD5-silenced cotton plants showed more sensitivity to Cd stress. The results indicate that GhHMAD5 is involved in Cd tolerance, which gives a preliminary understanding of the Cd tolerance mechanism in upland cotton. Overall, this study provides valuable information for the use of cotton to remediate soils polluted with Cd and potentially other heavy metals.

Transcriptome Analysis Unravels Key Factors Involved in Response to Potassium Deficiency and Feedback Regulation of K+ Uptake in Cotton Roots

“…Some reports showed that the quantity of DEGs under salt stress varied from 3800 to 22,000 in cotton [ 51 , 52 ]. Han et al identified 4627 DEGs in cotton under cadmium (Cd) toxicity [ 53 ]. In the present study, around 2000 and 2500 DEGs ( p -value < 0.05, and |log 2 (Fold Change) | ≥ 1.)…”

Genome-wide Identification and Function Analysis of HMAD&nbsp;Gene Family in Cotton (Gossypium Spp.)

“…For example, on the one hand, gene expression in ROS way and ion balance maintenance, such as Ca 2+ signaling pathway and MAPK, MYB transcription factor [62,63,64], programmed cell death [65,66,67]. And then the GSH, as the main way to remove ROS under the condition of high concentration, can not only response to heavy metal ions [68], also can response to salt stress ion [69]. At last, the balance of ions, such as anthocyanins were associated with the salt stress [58,59].…”

Transcriptome analysis of the impact of exogenous methyl jasmonate on the opening of sorghum florets

“…Then the GUS gene was replaced with two target gene LOC-1 and LOC-2 , which were added CaMV35s promoter and Nos terminator at 5’ and 3’ end, respectively. The constructed plasmid was transformed into Arabidopsis thaliana to verify its functions [ 31 ].…”