Comparative analysis of Cd-responsive maize and rice transcriptomes highlights Cd co-modulated orthologs

Area of Science:

• Plant Biology
• Genomics
• Environmental Stress Response

Background:

• Metal tolerance in plants is regulated by complex networks of metal uptake, distribution, signaling cascades, and transporters.
• Understanding these homeostatic mechanisms is crucial for improving crop resilience to heavy metal stress.

Purpose of the Study:

• To perform a comparative transcriptome analysis of maize roots under cadmium (Cd) stress.
• To identify conserved, differentially expressed genes (DEGs) in maize and rice in response to Cd.
• To advance the molecular understanding of Cd tolerance mechanisms in plants.

Main Methods:

• Comparative RNA sequencing (RNAseq) based transcriptome analysis of maize roots exposed to Cd stress.
• Identification and comparison of differentially expressed genes (DEGs) between maize and rice under Cd stress.
• Bioinformatic analysis to identify conserved orthologous groups and co-expression patterns.

Main Results:

• Identified 880 universal Cd-responsive orthologous groups between maize and rice, comprising 1074 maize DEGs and 981 rice counterparts.
• Discovered coordinated expression patterns in orthologous DEGs, including PDR-type ABC transporters, amino acid transporters, MATE efflux family transporters, HIPPs, and ZIPs.
• Identified novel Cd-responsive genes in maize (e.g., ZmHIPP27, ZmSNAC1, NCED) and demonstrated that ZmGAD1 confers Cd tolerance via heterologous expression.

Conclusions:

• Novel findings highlight conserved functions of Cd-responsive orthologs and paralogs in plants.
• These results are valuable for elucidating the genetic basis of plant responses to Cd stress.
• The study provides insights into potential Cd tolerance genes for crop improvement.