Synergistic Effects of Rhizobacteria and Salicylic Acid on Maize Salt-Stress Tolerance

Qasim Ali; Maqshoof Ahmad; Muhammad Kamran; Sana Ashraf; Muhammad Shabaan; Babar Hussain Babar; Usman Zulfiqar; Fasih Ullah Haider; M Ajmal Ali; Mohamed S Elshikh

doi:10.3390/plants12132519

Synergistic Effects of Rhizobacteria and Salicylic Acid on Maize Salt-Stress Tolerance

Plants (Basel). 2023 Jun 30;12(13):2519. doi: 10.3390/plants12132519.

Authors

Affiliations

¹ Department of Soil Science, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan.
² Pakistan Council for Science and Technology, Ministry of Science and Technology, Islamabad 44000, Pakistan.
³ College of Earth and Environmental Sciences, Quaid-e-Azam Campus, University of the Punjab, Lahore 54590, Pakistan.
⁴ Land Resources Research Institute (LRRI), National Agricultural Research Centre (NARC), Islamabad 44000, Pakistan.
⁵ Vegetable and Oilseed Section, Agronomic Research Institute, Faisalabad 38850, Pakistan.
⁶ Department of Agronomy, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan.
⁷ Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
⁸ University of Chinese Academy of Sciences, Beijing 100039, China.
⁹ Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.

Abstract

Maize (Zea mays L.) is a salt-sensitive plant that experiences stunted growth and development during early seedling stages under salt stress. Salicylic acid (SA) is a major growth hormone that has been observed to induce resistance in plants against different abiotic stresses. Furthermore, plant growth-promoting rhizobacteria (PGPR) have shown considerable potential in conferring salinity tolerance to crops via facilitating growth promotion, yield improvement, and regulation of various physiological processes. In this regard, combined application of PGPR and SA can have wide applicability in supporting plant growth under salt stress. We investigated the impact of salinity on the growth and yield attributes of maize and explored the combined role of PGPR and SA in mitigating the effect of salt stress. Three different levels of salinity were developed (original, 4 and 8 dS m^-1) in pots using NaCl. Maize seeds were inoculated with salt-tolerant Pseudomonas aeruginosa strain, whereas foliar application of SA was given at the three-leaf stage. We observed that salinity stress adversely affected maize growth, yield, and physiological attributes compared to the control. However, both individual and combined applications of PGPR and SA alleviated the negative effects of salinity and improved all the measured plant attributes. The response of PGPR + SA was significant in enhancing the shoot and root dry weights (41 and 56%), relative water contents (32%), chlorophyll a and b contents (25 and 27%), and grain yield (41%) of maize under higher salinity level (i.e., 8 dS m^-1) as compared to untreated unstressed control. Moreover, significant alterations in ascorbate peroxidase (53%), catalase (47%), superoxide dismutase (21%), MDA contents (40%), Na⁺ (25%), and K⁺ (30%) concentration of leaves were pragmatic under combined application of PGPR and SA. We concluded that integration of PGPR and SA can efficiently induce salinity tolerance and improve plant growth under stressed conditions.

Keywords: PGPR; ascorbate peroxidase; malondialdehyde; relative water contents; salicylic acid.

Grants and funding

This research received no external funding.