Tomato growth and resistance promotion by Enterobacter hormaechei subsp. steigerwaltii EB8D

Fusarium wilt is an economically important disease of tomato crop (Solanum lycopersicum L). Plant growth-promoting rhizobacteria (PGPR) represent an alternative to improve plant growth and yield as well as to act as agent of biocontrol. In this study, antagonistic effects of four selected isolates (EB8D, EB20J, EB24L and EB26M) were evaluated against Fusarium oxysporum f.sp. radicis lycopersici (FORL) as potential biocontrol agents in vitro and in vivo. After 30?days of culture, dry weight, length of stem and root were significantly (p?≤?.05) higher compared with the non-inoculated control. Compared with the control plate (inoculated only with pathogen), EB8D had showed efficient antagonism against FORL (48.88%). The different strains have been screened for siderophore production, solubilisation of mineral phosphates, synthesis of indolic acetic acid (IAA) to show the plant growth-promoting potential. The experimental groups were compared with a control group that did not receive any treatment by FORL, and EB8D was the best isolate in terms of growth promotion with an improvement of 73.85% of the stem length, 110.86% of the root length and 118.85% of the dry weight comparing with the non-treated controls. Compared with a control group treated by FORL, biocontrol activity has shown that EB8D strain improved the stem length with 111.85%, the root length with 118.85% and the dry weight with 452.38%. 16S rRNA analysis has confirmed that this strain belongs to the genus Enterobacter and has high similarity with Enterobacter hormaechei subsp. steigerwaltii (99.71%). EB8D has a significant strong protective potential against FORL and lead to better tomato growth and might have biotechnological potential for controlling fusarium wilt in tomato plants.