Zinc highly potentiates the plant defense responses against Macrophominaphaseolina in mungbean

Macrophomina phaseolina , is widely considered to be amongst the most important threatening fungal pathogen of over 750 plant species including mungbean. Synthetic chemical fungicides are not an appropriate option due to the robust nature of the fungal sclerotia. Zinc (Zn) is indispensable for the healthy development of plants, nontoxic in appropriate amount and display a broad-spectrum of strong antifungal activity at low concentration. In the current study, antimycotic and disease managing potential of ZnSO 4 was assessed in vitro and in vivo. Results indicated that in vitro, the fungal activity as growth, reproduction, biochemical, metal accumulation, and motility attributes were negatively affected by high levels of Zn ions (2.50–8.50 mM) in the growth medium. Complete growth inhibition was achieved at 16.50 mM. In planta , the pathogen caused 100% charcoal rot disease index, considerably reduced biophysical (growth and dry biomass) and biochemical traits (photosynthetic pigment, total protein content, catalase/CAT, peroxidase/POX, polyphenol oxidase/PPO and phenylalanine ammonia lyase /PAL) in the mungbean plants. However, the disease was noticeably suppressed (65, 40 and 15%) when exposed in vivo to foliar Zn concentrations (0.013, 0.025 and 0.037 Mm, respectively), along with noticeable improvement in the plant’s biophysical and biochemical traits. It was concluded that mungbean is metal non-accumulator species, where non-phytotoxic Zn concentration induced positive impact on plant resistance to M. phaseolina infection, hence well-qualify Zn to be applied directly to accomplish significant disease management in mungbean.