Funneliformis mosseae enhances drought tolerance in maize inbred lines through root transcriptomic reprogramming.

Area of Science:

• Plant Science
• Microbiology
• Genetics

Background:

• Drought significantly limits maize yield, necessitating enhanced stress tolerance strategies.
• Arbuscular mycorrhizal fungi (AMF) show potential for improving plant drought resilience.
• The intricate mechanisms of AMF-mediated drought tolerance involving root development, host gene regulation, and microbiome interactions are not fully understood.

Purpose of the Study:

• To investigate the integrated mechanisms of AMF-mediated drought tolerance in maize.
• To analyze genotype-specific responses to drought and AMF inoculation.
• To explore the interplay between host plant and root microbiome under stress.

Main Methods:

• Integrated phenotyping, transcriptomic (RNA-seq), and metatranscriptomic analyses were employed.
• Maize inbred lines (drought-tolerant and sensitive) and their hybrid were subjected to well-watered and drought conditions, with or without AMF (Funneliformis mosseae) inoculation.
• Differential gene expression and microbial functional activity patterns were analyzed.

Main Results:

• AMF colonization was effective, particularly under drought conditions.
• Genotype was the primary driver of transcriptional variation, with sensitive genotypes showing more differentially expressed genes.
• AMF induced genotype-specific reprogramming, with tolerant genotypes showing moderated stress responses and sensitive genotypes exhibiting compensatory metabolic activation.
• The hybrid displayed non-additive responses, including root remodeling and enhanced symbiosis functions.
• Metatranscriptomics revealed genotype-specific microbial functional activity.

Conclusions:

• AMF-mediated drought tolerance in maize is a complex trait arising from coordinated, genotype-dependent interactions between root development, host regulatory networks, and the root microbiome.
• This study provides a holobiont-level framework for understanding and improving crop adaptation to drought stress.
• Understanding these interactions is crucial for developing climate-resilient crops.