Preliminary screening of indigenous bacterial isolates from soil and fish pond sediments for their beneficial effect on vegetables grown and health
2012
Tringovska, I. | Kostova, D. | Masheva, S. | Yankova, V. | Pasev, G.
Plants interaction with beneficial microorganisms could result in a significant growth response and also could increase the host tolerance to pathogens. In search of efficient for vegetables growing Plant Growth Promoting Rhizobacterial (PGPR) strains a number of isolates were separated from different soils and fish-pond sediments in Bulgaria. These isolates were screened initially in vitro for some plant growth promoting traits like production of siderophores, phosphate solubilization and antimicrobial activity. Pot experiments in growing chambers were carried out with some of the best performed after in vitro tests isolates, aiming further to screen their ability to improve plant growth as well as to improve the level of resistance against several economically important pests on tomato and cucumber. Seeds or plant’s roots were treated with bacterial suspensions. The plants were grown in sterile perlite or non-sterile mixture peat:perlite, supplemented with nutrient solution. Plant growth promotion was assessed by fresh shoot weight, while the efficacy against Cucumber mosaic virus (CMV) was assessed by index of depression, based on biometric data, and serologically by indirect ELISA; against Meloidogyne spp. – by root galling index and some biometric data; against Fusarium oxysporum f. sp. radicis cucumerinum and Pythium sp. – by index of infestation and biometric data. After screening of more than hundred isolates a few were selected for their multiply beneficial functions as positive influence on plant growth and health. In a time course study several isolates were selected for their ability to reduce disease severity and viral titer of CMV on susceptible cucumber cultivar. Some of the selected isolates confirmed their positive effects also against Meloidogyne spp., Fusarium oxysporum f. sp. radicis cucumerinum and Pythium spp. Further evaluation of the isolates exhibiting beneficial effect is needed to uncover their efficacy as PGPR that could be used in horticulture as low-input and multifunctional agents.
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