Molecular Mechanisms of Growth and Salt Tolerance in Diverse Rice Cultivars Balanced by Rhodobium marinum RH-AZ

Area of Science:

• Plant Science
• Microbiology
• Genetics

Background:

• Salt stress significantly hinders rice (Oryza sativa) yield, necessitating sustainable solutions.
• Plant-microbial interactions offer a promising avenue for improving crop resilience to abiotic stresses like salinity.
• Understanding the molecular basis of microbial-mediated stress tolerance is crucial for agricultural advancement.

Purpose of the Study:

• To elucidate the molecular mechanisms underlying salt tolerance enhancement in rice by Afifella marina RH-AZ.
• To compare the cultivar-dependent responses of salt-sensitive (9311) and moderately salt-tolerant (3931) rice to RH-AZ treatment under salt stress.
• To identify conserved pathways and regulatory networks modulated by RH-AZ treatment.

Main Methods:

• Integrated transcriptomic and physiological analyses were performed on rice cultivars 9311 and 3931.
• Weighted Gene Co-expression Network Analysis (WGCNA) was employed to identify key gene modules.
• Hormonal profiling (IAA/ABA, JA/SA signaling) was conducted to assess regulatory network modulation.

Main Results:

• RH-AZ treatment alleviated salt-induced growth inhibition and oxidative damage in both rice cultivars.
• Cultivar 3931 exhibited a broader transcriptional response and more effective hormonal regulation (IAA/ABA, JA/SA) compared to cultivar 9311.
• A conserved module related to diterpenoid biosynthesis was identified as significantly enhanced by RH-AZ treatment.

Conclusions:

• Afifella marina RH-AZ enhances rice salt stress adaptation through potentiation of basal defense, hormonal homeostasis, and secondary metabolism.
• Cultivar 3931 demonstrated superior genetic plasticity in leveraging RH-AZ stimuli for enhanced salt tolerance.
• Microbial treatments represent a viable strategy for improving rice productivity in saline environments.