Harnessing chickpea (Cicer arietinum L.) seed endophytes for enhancing plant growth attributes and bio-controlling against Fusarium sp.

A seed microbiome is likely to have important impacts on plant fitness and productivity but functional potentials of seed microbiome remain poorly understood. It is also suggested that bio-inoculants developed from or compatible with seed microbiome are more likely to produce desired outcomes of sustainable increase in agriculture productivity but few empirical evidences are available. The aim of this study was to identify culturable endophytes of the germinating and dry seeds of chickpea (Cicer arietinum L.), and their functional attributes. We isolated 29 bacterial strains from chickpea seeds (8 strains from dry and 21 strains from germinating seeds). Phylogenetic analysis based on 16S rDNA showed that the seed endophytic bacteria belong to Enterobacter sp., Bacillus sp., Pseudomonas sp., Staphylococcus sp., Pantoea sp. and Mixta sp. Isolates produced significant amount of Indole-3-acetic acid (IAA) (Enterobacter hormaechei BHUJPCS-15; 58.91 μg/ml), solubilised phosphate (Bacillus subtilis BHUJPCS-24; 999.85 μg/ml) and potassium, ammonia (Bacillus subtilis BHUJPCS-12; 148.73 μg/ml), and also inhibited the growth of chickpea pathogen (Pseudomonas aeruginosa BHUJPCS-7 against Fusarium oxysporum f.sp. ciceris) under laboratory conditions. Several seed endophytes induced significant increase in plant growth and increased tolerance of chickpea plants to the pathogen (Fusarium oxysporum f.sp. ciceris) when tested in vitro. Re-introduction of these isolates, resulted in significant increase in plant length, biomass and chlorophyll contents and bio-controlling activity against Fusarium oxysporum f.sp. ciceris. These results provide a direct evidence for the presence of beneficial seed microbiome and suggest these isolates could be further developed into potential bio-inoculants for improving diseases management and sustainable increase in agriculture productivity.