Screening of five mulberry (Morus spp.) cultivars for safe utilization of arsenic-contaminated tailings

Mulberry cultivation for sericulture provides both ecological and economic benefits, supporting green mining strategies. This study evaluated the safety and suitability of five mulberry cultivars (G62, Y120, G12, J, F) from two species Morus atropurpurea and Morus alba, grown in arsenic (As)-contaminated tailing soils for silkworm rearing. After six months of cultivation, all cultivars exhibited reduced growth, with Y120 showing the highest tolerance and minimal growth inhibition, while F was the most sensitive. Arsenic accumulation followed the order root > leaf > stem, with J and F displaying 2.0-3.9 times higher root As concentrations than Y120 and G62. All cultivars reduced rhizosphere soil As through phytoremediation, with F achieving the highest reduction (38.38%). Silkworms fed As-contaminated leaves showed delayed development, increased leaf consumption, and decreased survival rates, particularly in the 5th instar. Y120-fed silkworms had the highest survival (86.11%) and cocooning rates (83.33%), while F-fed silkworms had the lowest (50.56% survival, 26.67% cocooning). Gut microbiota analyses revealed cultivar-specific shifts in bacterial diversity. Importantly, As levels in silkworm products remained within safety limits, with bioaccumulation highest in feces and lowest in cocoons. Based on 26 safety indicators, Y120 ranked as the most suitable cultivar for sericulture in As-contaminated soils, ensuring safe and sustainable mulberry-silkworm production.