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Kushwaha AS, Ahmad I, Lata S, Padalia K, Yadav AK, Kumar M. Mycorrhizal fungus Serendipita indica-associated acid phosphatase rescues the phosphate nutrition with reduced arsenic uptake in the host plant under arsenic stress. Ecotoxicol Environ Saf 2024; 269:115783. [PMID: 38061081 DOI: 10.1016/j.ecoenv.2023.115783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 01/12/2024]
Abstract
Symbiotic interactions play a vital role in maintaining the phosphate (Pi) nutrient status of host plants and providing resilience during biotic and abiotic stresses. Serendipita indica, a mycorrhiza-like fungus, supports plant growth by transporting Pi to the plant. Despite the competitive behaviour of arsenate (AsV) with Pi, the association with S. indica promotes plant growth under arsenic (As) stress by reducing As bioavailability through adsorption, accumulation, and precipitation within the fungus. However, the capacity of S. indica to enhance Pi accumulation and utilization under As stress remains unexplored. Axenic studies revealed that As supply significantly reduces intracellular ACPase activity in S. indica, while extracellular ACPase remains unaffected. Further investigations using Native PAGE and gene expression studies confirmed that intracellular ACPase (isoform2) is sensitive to As, whereas extracellular ACPase (isoform1) is As-insensitive. Biochemical analysis showed that ACPase (isoform1) has a Km of 0.5977 µM and Vmax of 0.1945 Unit/min. In hydroponically cultured tomato seedlings, simultaneous inoculation of S. indica with As on the 14thday after seed germination led to hyper-colonization, increased root/shoot length, biomass, and induction of ACPase expression and secretion under As stress. Arsenic-treated S. indica colonized groups (13.33 µM As+Si and 26.67 µM As+Si) exhibited 8.28-19.14 and 1.71-3.45-fold activation of ACPase in both rhizospheric media and root samples, respectively, thereby enhancing Pi availability in the surrounding medium under As stress. Moreover, S. indica (13.33 µM As+Si and 26.67 µM As+Si) significantly improved Pi accumulation in roots by 7.26 and 9.46 times and in shoots by 4.36 and 8.85 times compared to the control. Additionally, S. indica induced the expression of SiPT under As stress, further improving Pi mobilization. Notably, fungal colonization also restricted As mobilization from the hydroponic medium to the shoot, with a higher amount of As (191.01 ppm As in the 26.67 µM As+Si group) accumulating in the plant's roots. The study demonstrates the performance of S. indica under As stress in enhancing Pi mobilization while limiting As uptake in the host plant. These findings provide the first evidence of the As-Pi interaction in the AM-like fungus S. indica, indicating reduced As uptake and regulation of PHO genes (ACPase and SiPT genes) to increase Pi acquisition. These data also lay the foundation for the rational use of S. indica in agricultural practices.
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Affiliation(s)
- Aparna Singh Kushwaha
- Environmental Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Imran Ahmad
- Environmental Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Sneh Lata
- Analytical Chemistry Laboratory, Regulatory Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Kalpana Padalia
- Analytical Chemistry Laboratory, Regulatory Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India
| | - Akhilesh Kumar Yadav
- Analytical Chemistry Laboratory, Regulatory Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India
| | - Manoj Kumar
- Environmental Toxicology Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh 201002, India.
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