Seed coating with novel sodium alumino silicate margosa composite – A proficient technique to reduce mycotoxins of Fusarium fujikuroi species complex inciting discoloration of rice

Abstract

Infestation of fungi during storage of grains causes about 4.6–6% wastage of cereal grains. Among other fungi Fusarium fujikuroi speciescomplex (FFSC) is one of the major causes of grain discoloration of rice. Due to the negative impacts of toxicgenic FFSC complex on seed health and quality metrics, it significantly reduces the market value of rice seeds. Apart from nutrient losses to rice seeds toxic fungal metabolites like fumonisin B1, fumonisin B2, fusaric acid, and gibberellic acid produced by FFSC complex interacts with physiological parameters influencing the integrity of seeds during storage. Due to the detrimental effects on seed germination and vitality, chemical seed treatments are usually avoided while the seeds are in storage. This paper presents the efficacy of novel sodium alumino silicate (SAS)-Margosa composite against toxigenic FFSC complex viz., F. fujikuroi, F. verticillioides, and F. proliferatum during storage of rice seeds with augemented antitoxin and seed invigorating potential. The novel SAS-Margosa composite was chemically and morphologically characterized using XRD, FTIR, TEM, and EDS analysis. The antifungal potential of margosa leaf extract adsorbed nanosilicate material (SAS) was examined using SEM, Flourescence microscopy and poison food technique. The toxin quantification of FFSC complex inoculated seeds treated with SAS-Margosa composite was carried out at monthly intervals upto a period of six months of storage along with control on two rice varieties viz., PR114 and Pusa Basmati 1121 respectively. The study revealed that SAS-Margosa composite coated seeds of PR114 and Pusa Basmati 1121 exhibited significanlty higher seed germination (87.63 & 83.57%) and minimum seed rot (5.70 & 5.24%) after 6 months of storage as compare to control. There was a significant decrease in levels of fusaric acid, fumonisins B1, B2 and gibberellic acid after six months as compare to control in both the varieties. The SAS-Margosa composite has been proved to be effective against toxigenic FFSC complex during rice seed storage without compromising the seed quality metrics.