Symbiotic System Establishment between Piriformospora indica and Glycine max and Its Effects on the Antioxidant Activity and Ion-Transporter-Related Gene Expression in Soybean under Salt Stress

Abstract

The utilization of symbiosis with beneficial microorganisms has considerable potential for increasing growth and resistance under abiotic stress. The endophytic root fungus Piriformospora indica has been shown to improve plant growth under salt and drought stress in diverse plant species, while there have been few reports of the interaction of P. indica with soybean under salt stress. In this study, the symbiotic system of P. indica and soybean (Glycine max L.) was established, and the effect of P. indica on soybean growth and salt tolerance was investigated. The colonized and non-colonized soybeans were subjected to salt stress (200 mmol/L NaCl), and the impairments in chlorophyll and increasing relative conductivity that can be caused by salt stress were alleviated in the P. indica-colonized plants. The accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anion (O2−) were lower than that in non-colonized plants under salt treatment, whereas the activities of antioxidant enzymes were significantly increased by P. indica colonization, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione reductase (GR). Importantly, without salt treatment, the Na+ concentration was lower, and the K+ concentration was higher in the roots compared with non-colonized plants. Differential expressions of ion transporter genes were found in soybean roots after P. indica colonization. The P. indica colonization positively regulated the transcription level of PM H+-ATPase, SOS1, and SOS2. The study shows that P. indica enhances the growth and salt tolerance of soybean, providing a strategy for the agricultural production of soybean plants in saline-alkali soils.

Exogenous Selenium Endows Salt-Tolerant and Salt-Sensitive Soybeans with Salt Tolerance through Plant-Microbial Coactions

“…In saline soil, the redox balance within soybean plants is disrupted, resulting in excessive production of reactive oxygen species and triggering oxidative stress responses that damage cell membranes and organelles [16]. Moreover, the imposition of salt stress disrupts the crucial processes of water and nutrient absorption in the intricate root architecture of soybeans, particularly concerning essential metal cations, thereby precipitating imbalances in nutrient distribution [17,18]. This disruption affects physiological metabolic processes in soybeans, inhibiting photosynthesis, respiration and nitrogen metabolism, thereby limiting plant growth and development [19].…”

The Influence of Piriformospora indica Colonization on the Root Development and Growth of Cerasus humilis Cuttings

“…Chlorophyll is a key photosynthetic pigment, and increasing its content helps improve the efficiency of plant photosynthesis, carbon fixation capacity, and stress resistance, thereby promoting plant growth [ 40 ]. Numerous studies have indicated that P. indica colonization can increase the chlorophyll content of plants such as Anthurium [ 41 ], soybeans [ 42 ], and Torreya grandis cuttings [ 43 ]. P. indica can enlarge the leaf area of Tartary buckwheat, thereby enhancing its photosynthesis [ 39 ].…”

Research Progress of Piriformospora indica in Improving Plant Growth and Stress Resistance to Plant

“…The transcription levels of genes such as OsNAC1, OsNAC6, OsBZIP23, and OsDREB2A are upregulated in rice seedling leaves colonized by P. indica, contributing to enhanced salt tolerance [51]. Moreover, P. indica colonization positively regulates the transcript levels of PMH + ATPase, SOS1, and SOS2, thereby improving soybean growth and salt tolerance [52]. Epigenetic studies have found that P. indica-colonization conferred maize greater salinity tolerance by increasing methylation levels in leaves and changing DNA methylation [53,54].…”