Efficacy of cadmium tolerant bacteria in combination with jasmonic acid to alleviate cd-toxicity in cauliflower

Abstract

Application of untreated wastewater for vegetable production in peri-urban areas enters into the food chain leading to compromised human health. The present study was planned to evaluate the potential of cadmium (Cd) tolerant bacterial strains in combination with foliar application of Jasmonic acid (JA) under Cd stress. The Cd tolerant bacterial strains were isolated from wastewater and characterized for the production of exopolysaccharides (EPS), siderophore, and indole acdetic acid (IAA) under in vitro studies. The four most efficient strains SS5, SS7, SS8, and SS10 were selected based on growth-promoting traits and further evaluated with different levels of JA (20 μmol L-1 and 40 μmol L-1) in jar trial. Cauliflower (hyperaccumulator) was used as a test crop with Cd levels (0 and 150 mg kg-1). Our results depicted that the use of consortium (SS7+SS8) along with a foliar application of JA (40 μmol L-1) significantly improved shoot dry weight (15.5%), root dry weight (28.4%), shoot length (23.7%), root length (37%), superoxide dismutase (29.8%), peroxidase dismutase (29.7%), catalase (31.7%) and POX (29.2%). However, 29 and 26% reduction in Cd concentration in shoots and roots was observed, respectively. It was concluded that the Klebsiella strains SS7 and SS8 with foliar application of JA is a potential biofertilizer and a phyto-stabilizer for metal-contaminated soils and recommended to reduce the Cd toxicity among crop plants.