Comparative Transcriptome Analysis of Ectomycorrhizal Fungus Pisolithus albus in Response to Individual and Combined Stress of Copper and Cadmium
Eetika Chot1, Krishna Mohan Medicherla2, and Mondem Sudhakara Reddy1*
1Thapar Institute of Engineering and Technology, Bhadson Road, Patiala, Punjab,147004, India
2Birla Institute of Scientific Research, Statue Circle, Jaipur, 302001, India
In recent years, the increasing soil heavy metal (HM) pollution has gathered global awareness due to its critical threat to human health through food chain transfer. A symbiosis of an ectomycorrhizal fungus Pisolithus albus not only regulates the HM transportation from soil to host plant but also significantly improves their growth and survival on metal contaminated land. The successful utilization of P. albus in rehabilitation programs of HM-polluted barren lands requires a basic understanding of fungal key genes and mechanisms involved in metal tolerance. Therefore, the RNA Sequencing and transcriptome analysis of P. albus under individual and combined stress of copper and cadmium was performed in the current study. Among 11 differentially expressed pathways induced by metal stress, the carbohydrate, lipid, and amino acids pathways were highly impacted. The functional enrichment of differentially expressed genes (DEGs) showed the essential role of fungal folate, arginine, melanin, fatty acids, membrane phospholipids, metal chelating agents, and other antioxidant agent metabolism in HM stress. A significant differential expression of zinc, potassium, iron, and amino acid transportation related genes showed their crucial role in metal tolerance. The induction of antioxidant defense machinery, correct protein folding, and metal sequestration via chelating agents and further transportation to vacuoles; the regulation of cell wall adaptations and mineral influxes were found as top tolerance mechanisms of fungus against metal stress. The RT-qPCR analysis of selected DEGs showed the high credibility of the presented RNA-Sequencing analysis.