Speakers - 2026

Title: Microbial consortia enhance tomato growth and phytoremediation related traits under copper stress and wastewater irrigation

Abstract

The increasing use of wastewater for agricultural irrigation and the accumulation of heavy metals in cultivated soils pose major challenges for sustainable horticultural production Copper Cu although an essential micronutrient becomes phytotoxic at elevated concentrations reducing seed germination root development and overall plant performance Plant growthpromoting rhizobacteria PGPR have emerged as an environmentally friendly strategy for mitigating abiotic stress and improving crop productivity However limited information is available regarding the combined effects of temperature copper stress wastewater irrigation and PGPR inoculation throughout the early developmental stages of tomato This study evaluated the effects of two PGPR consortia on germination seedling vigor vegetative growth root architecture leaf development and biomass accumulation in three tomato Solanum lycopersicum L genotypes RG22 RG19 and the native variety Rn22 The research combined laboratory germination assays with greenhouse experiments under cleanwater and wastewater irrigation allowing the evaluation of plant responses from seed germination through early vegetative growth Temperature was the principal factor regulating germination Germination increased from 86 at 18C to 97 at 28C but declined sharply at 33C and was completely inhibited at 35C Increasing CuSO concentrations significantly reduced germination percentage delayed the time required to reach 50 germination T and decreased seedling vigor with the strongest effects observed at 10 M CuSO RG22 showed the greatest tolerance to copper stress whereas the native variety Rn22 was the most sensitive PGPR inoculation substantially improved early plant development Root length increased by 447 and root dry biomass by 922 during the seedling stage Under greenhouse conditions plant responses were genotype dependent consortium 1 produced the greatest improvements in RG22 consortium 3 was more effective in RG19 and Rn22 responded positively to both consortia PGPR inoculation increased root length by up to 235 root volume by 411 leaf area by approximately 28 shoot dry biomass by 573 and root dry biomass by nearly 27 relative to uninoculated controls Although copper uptake and bioaccumulation were not quantified the improvements in root architecture biomass production and vegetative growth represent important phytoremediationrelated traits that favor plant establishment under contaminated conditions These findings demonstrate that carefully selected PGPR consortia constitute an effective biological strategy for improving tomato performance under copper stress and wastewater irrigation and provide a foundation for sustainable horticultural production and future phytoremediationoriented management systems