Trichoderma asperellum 22043: Inoculation Promotes Salt Tolerance of Tomato Seedlings Through Activating the...

Area of Science:

• Plant Science
• Agricultural Microbiology
• Stress Physiology

Background:

• Salt stress significantly hinders crop productivity, particularly in essential crops like tomatoes.
• Developing salt-tolerant varieties through traditional breeding methods presents considerable challenges.
• Microbial inoculants offer a promising alternative strategy for enhancing plant resilience to abiotic stresses.

Purpose of the Study:

• To investigate the efficacy of Trichoderma asperellum 22043 in improving salt tolerance in tomato plants.
• To elucidate the underlying physiological and molecular mechanisms by which T. asperellum enhances stress resistance.
• To assess the impact of T. asperellum on key growth parameters and stress indicators in salt-affected tomato seedlings.

Main Methods:

• Tomato seeds were subjected to salt stress (50 and 100 mM NaCl) with and without inoculation of T. asperellum 22043 spore suspension.
• Evaluated germination rates, seedling survival, plant height, and chlorophyll content.
• Measured malondialdehyde (MDA) and proline levels as indicators of oxidative stress and osmotic adjustment.
• Analyzed the transcriptional levels of genes involved in reactive oxygen species (ROS) scavenging, ion transport, and aquaporin activity.

Main Results:

• T. asperellum 22043 inoculation significantly increased seed germination and seedling survival rates under salt stress.
• Inoculated plants showed enhanced plant height and chlorophyll content compared to non-inoculated controls.
• Malondialdehyde and proline accumulation were reduced in T. asperellum-treated plants, indicating lower oxidative damage and osmotic stress.
• T. asperellum modulated the expression of ROS-scavenging enzyme genes and genes related to Na+ transporters and aquaporins.

Conclusions:

• Trichoderma asperellum 22043 effectively enhances the salt tolerance of tomato seedlings.
• The fungus confers stress resistance by activating the plant's antioxidant defense system.
• T. asperellum regulates the expression of stress-responsive genes, including those for transporters and aquaporins, to maintain cellular homeostasis under saline conditions.