Characterization of the plant growth promoting bacterium, Enterobacter cloacae MSR1, isolated from roots of non-nodulating Medicago sativa

Abstract

The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future.

Influences of Climate on Phyllosphere Endophytic Bacterial Communities of Wild Poplar

“…Enterobacteriaceae and Pseudomonadaceae are capable of secreting secondary metabolites or produce enzymes that enhance drought tolerance. For instance, volatile organic compounds such as acetoin and butanediol elicits stomatal closure, helping the plant prevent water loss from transpiration (Cho et al, 2008) and improving drought tolerance (Saha and Bothast, 1999;Celińska and Grajek, 2009;Ji et al, 2011;Khalifa et al, 2016). In addition, Pseudomonas, Klebsiella, Erwinia, Serratia and Pantoea species are known to be ACC deaminase-producing bacteria and therefore able to regulate plant ethylene levels inducing tolerance to drought stress (Li et al, 2015;Saikia et al, 2018;Danish and Zafar-ul-Hye, 2019).…”

Cloning and characterization of short‐chain N‐acyl homoserine lactone‐producing Enterobacter asburiae strain L1 from lettuce leaves

“…This isolate was found to secrete N-butanoyl homoserine lactone (C4-HSL) and N-hexanoyl homoserine lactone (C6-HSL) (Lau, Sulaiman, Chen, Yin, & Chan, 2013;Lau, Yin, & Chan, 2014). Previous studies have shown that E. asburiae strains have been isolated from water, soil, food, and human sources, that is, blood culture, wounds, and exudates as well as from respiratory sources (Brenner, McWhorter, Kai, Steigerwalt, & Farmer, 1986; Castellanos-Arévalo, Castellanos-Arévalo, Camarena-Pozos, Colli-Mull, & Maldonado-Vega, 2015; Khalifa, Alsyeeh, Almalki, & Saleh, 2015;Shin et al, 2007). Although its exact clinical value is yet to be discovered and very little is known about its pathogenicity and virulence, these findings suggested the clinical significance of E. asburiae.…”

Identification and determination of characteristics of endophytes from rice plants and their role in biocontrol of bacterial blight caused by Xanthomonas oryzae pv. oryzae

“…Of Enterobacter spp., Enterobacter radicincitans in cereals (Witzel et al, 2012), Enterobacter sp. SP1 in sugar cane (Zhu et al, 2012) and Enterobacter cloacae MSR1 in alfalfa (Khalifa et al, 2016) have shown an ability to increase production in plants. The production of plant hormones by the Enterobacter sp.…”