Arbuscular Mycorrhizas Regulate Photosynthetic Capacity and Antioxidant Defense Systems to Mediate Salt Tolerance in Maize

Abstract

Salt stress inhibits photosynthetic process and triggers excessive formation of reactive oxygen species (ROS). This study examined the role of arbuscular mycorrhizal (AM) association in regulating photosynthetic capacity and antioxidant activity in leaves of two maize genotypes (salt-tolerant JD52 and salt-sensitive FSY1) exposed to salt stress (100 mM NaCl) in soils for 21 days. The leaf water content, chlorophyll content, and photosynthetic capacity in non-mycorrhizal (NM) plants were decreased by salt stress, especially in FSY1, with less reduction in AM plants than NM plants. Salinity increased the activities of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR)) in both genotypes regardless of AM inoculation, but decreased the contents of non-enzymatic antioxidants (reduced glutathione (GSH) and ascorbate (AsA)), especially in FSY1, with less decrease in AM plants than NM plants. The AM plants, especially JD52, maintained higher photosynthetic capacity, CO2 fixation efficiency, and ability to preserve membrane integrity than NM plants under salt stress, as also indicated by the higher antioxidant contents and lower malondialdehyde (MDA)/electrolyte leakage in leaves. To conclude, the higher salt tolerance in AM plants correlates with the alleviation of salinity-induced oxidative stress and membrane damage, and the better performance of photosynthesis could have also contributed to this effect through reduced ROS formation. The greater improvements in photosynthetic processes and antioxidant defense systems by AM fungi in FSY1 than JD52 under salinity demonstrate genotypic variation in antioxidant defenses for mycorrhizal amelioration of salt stress.

Does co-inoculation of mycorrhiza and Piriformospora indica fungi enhance the efficiency of chlorophyll fluorescence and essential oil composition in peppermint under irrigation with saline water from the Caspian Sea?

“…Similar findings were reported in other plants in which salinity induced changes [ 44 , 45 ]. It is known that reduction in the chlorophyll content under salt stress reduces light reactions and electron transport in PS II from primary to secondary acceptor [ 46 ].…”

Effectiveness of gypsum application and arbuscular mycorrhizal fungi inoculation on ameliorating saline-sodic soil characteristics and their productivity.

“…AMF is considered to promote plant growth and salinity tolerance (Evelin et al, 2019). The AMF improved antioxidant systems in stress plants have been reported in Wheat (Abdel Latef, 2010) and Maize (Wang et al, 2020). Additionally, it can alleviate salt stress by decreasing oxidative stress in plants and improved concentrations of osmolytes such as proline, polyamines, and glycine betaine (Frosi et al, 2018); enhancing lipids and proteins, quenching free radicals, and buffering cellular redox potential under salinity stress (Yang et al, 2008); improving in photosynthetic activity (Wang et al, 2022) due to mycorrhizal colonization in plants are limited the Na + transport (Zhu et al, 2010), energizing carbohydrate transport and metabolism (Kaschuk et al, 2009), increasing the leaf area and higher stomatal conductance and consequently better assimilation CO 2 due to improving water situation in plants (Chen et al, 2017).…”

Physiological and Enzymatic Antioxidant Responses of Solanum tuberosum Leaves to Arbuscular Mycorrhizal Fungal Inoculation under Water Stress

“…Moreover, Cayún et al [ 18 ] reported similarities between potato plants inoculated with AMF and control plants with respect to the photosynthetic rate and an increase in the concentration of chlorophyll in AMF-inoculated samples. AMF inoculation reportedly increases enzymatic antioxidant activity in corn, olive, and potato leaves and roots [ 19 , 20 , 21 ]. AMF root colonisation also causes changes in root exudates, increasing the contents of low-molecular-weight organic acids (LMWOAs) secreted by maize and potato plants [ 18 , 22 ].…”