Mitigation of Extreme Salinity Stress at Flowering Stage by Piriformospora indica in Contrasting Rice Genotypes
摘要
Rice (Oryza sativa L.), the principal staple food for a large portion of the global population, faces severe productivity challenges due to salinity stress, an increasingly prevalent problem aggravated by climate change. Salinity adversely affects rice growth and yield, particularly at critical developmental stages. This study assessed the potential of the root-colonizing endophytic fungus Piriformospora indica as a biological strategy to enhance salinity tolerance in rice plants. Two contrasting genotypes, Manu Ratna (salinity-sensitive) and Vyttila‑6 (salinity-tolerant), were evaluated under controlled, high (200 mM NaCl) and extreme (300 mM NaCl) salinity conditions to examine morpho-physiological and biochemical responses at the flowering stage because damage at flowering is largely irreversible, making this stage more decisive for stress tolerance evaluation. P. indica-colonized plants exhibited superior performance compared with uninoculated controls, showing improvements in specific leaf area (14.22%), chlorophyll content (22.19%), membrane stability (28.45%), and proline accumulation (59%), with reductions in malondialdehyde (55.84%) and Na+/K+ ratio (11.6%). P. indica significantly enhanced root development, essential for water and nutrient uptake under saline conditions. Our results showed the prospect of P. indica colonization as an effective approach to enhance rice resilience to salinity stress. This study highlights P. indica as a promising bioinoculant for improving rice resilience and sustainable cultivation in salt-affected soils.