Aspergillus welwitschiae BK Isolate Ameliorates the Physicochemical Characteristics and Mineral Profile of Maize under Salt Stress

Humaira Gul; Raid Ali; Mamoona Rauf; Muhammad Hamayun; Muhammad Arif; Sumera Afzal Khan; Zahida Parveen; Abdulwahed Fahad Alrefaei; In-Jung Lee

doi:10.3390/plants12081703

Aspergillus welwitschiae BK Isolate Ameliorates the Physicochemical Characteristics and Mineral Profile of Maize under Salt Stress

Plants (Basel). 2023 Apr 19;12(8):1703. doi: 10.3390/plants12081703.

Authors

Humaira Gul¹, Raid Ali¹, Mamoona Rauf¹, Muhammad Hamayun¹, Muhammad Arif², Sumera Afzal Khan³, Zahida Parveen⁴, Abdulwahed Fahad Alrefaei⁵, In-Jung Lee⁶

Affiliations

¹ Department of Botany, Garden Campus, Abdul Wali Khan University Mardan, Khyber Pakhtunkhwa, Mardan 23200, Pakistan.
² Department of Biotechnology, Garden Campus, Abdul Wali Khan University Mardan, Khyber Pakhtunkhwa, Mardan 23200, Pakistan.
³ Center of Biotechnology and Microbiology, University of Peshawar, Peshawar 25120, Pakistan.
⁴ Department of Biochemistry, Garden Campus, Abdul Wali Khan University Mardan, Khyber Pakhtunkhwa, Mardan 23200, Pakistan.
⁵ Department of Zoology, College of Science, King Saud University, Riyadh 2455, Saudi Arabia.
⁶ Department of Applied Biosciences, Kyungpook National University, Daegu 41566, Republic of Korea.

Abstract

Abiotic stressors are global limiting constraints for plant growth and development. The most severe abiotic factor for plant growth suppression is salt. Among many field crops, maize is more vulnerable to salt, which inhibits the growth and development of plants and results in low productivity or even crop loss under extreme salinity. Consequently, comprehending the effects of salt stress on maize crop improvement, while retaining high productivity and applying mitigation strategies, is essential for achieving the long-term objective of sustainable food security. This study aimed to exploit the endophytic fungal microbe; Aspergillus welwitschiae BK isolate for the growth promotion of maize under severe salinity stress. Current findings showed that salt stress (200 mM) negatively affected chlorophyll a and b, total chlorophyll, and endogenous IAA, with enhanced values of chlorophyll a/b ratio, carotenoids, total protein, total sugars, total lipids, secondary metabolites (phenol, flavonoids, tannins), antioxidant enzyme activity (catalase, ascorbate peroxidase), proline content, and lipid peroxidation in maize plants. However, BK inoculation reversed the negative impact of salt stress by rebalancing the chlorophyll a/b ratio, carotenoids, total protein, total sugars, total lipids, secondary metabolites (phenol, flavonoids, tannins), antioxidant enzyme activity (catalase, ascorbate peroxidase), and proline content to optimal levels suitable for growth promotion and ameliorating salt stress in maize plants. Furthermore, maize plants inoculated with BK under salt stress had lower Na⁺, Cl^- concentrations, lower Na^+/K⁺ and Na⁺/Ca²⁺ ratios, and higher N, P, Ca²⁺, K⁺, and Mg²⁺ content than non-inoculated plants. The BK isolate improved the salt tolerance by modulating physiochemical attributes, and the root-to-shoot translocation of ions and mineral elements, thereby rebalancing the Na⁺/K⁺, Na⁺/Ca²⁺ ratio of maize plants under salt stress.

Keywords: endogenous hormones; endophytic fungi; maize; potassium; proline; salinity; sodium.

Abstract

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