Phenotypic Variations of Endophytic Bacteria Associated with Carob Tree (Ceratonia Siliqua L.)

Abstract

Abstract:We aimed to characterize 83 endophytic bacteria isolated from roots (73 isolates coded IRC) and epicotyls (11 isolates coded IEC) of young Carob (Ceratonia siliqua L.) seedlings. These seedlings were obtained from seeds collected in several regions in Morocco. 30 IRC and 4 IEC were selected on the basis of PCR-Pep for the further analyses. All the strains exhibited a wide tolerance to NaCl and 30 % tolerated well concentration up to 11 % NaCl. Strains showed also a wide tolerance to the variable pH. 60 % of strains grew well at pH4. Most of the strains were resistant to different antibiotics but were sensitive to kanamycin and tetracycline. The strains showed a resistance to heavy metals except mercury chloride that was toxic at a low concentration 50 µg.ml-1. According to their phenotypical features, the associative bacteria were very similar to eight symbiotic bacteria previously identified by Missbah in 1996 and used in this work.

Characterization of Indigenous Rhizobia Strains Associated to Soybean [Glycine max (L.) Merrill] in Benin

“…Strains exhibited a great tolerance to salinity since some of them were able to grow in 9% NaCl. This NaCl tolerance range agreed with previous reports [7,14]. According to Konate et al [14], salt tolerance strains can give to rhizobial strains advantages to survive, multiply in saline soil and efficiency infect their host plants.…”

“…Their resistance to metals is very similar to what it knows in general on Rhizobia. Tolerance to heavy metals could be exploited in the bioremediation trials aimed at improving the quality of soil contaminated with heavy metals sites [14,25].…”

“…All isolates were examined for their tolerance to salt on YEMA supplemented with 1, 2, 3, 4, 5, 7, 8 and 9% of NaCl (w/v) [14,1]). The medium YEMA was used as control.…”

“…The resistance of strains to heavy metals was also determined on solid YEM medium. The stock solutions of metals were filter-sterilized and added to sterile YEM medium as following concentrations: 500 µg/ml for MnCl 2 , 100 µg/ml for CuSO 4 , ZnCl 2 and HgCl 2 [14].…”

Plant Beneficial Endophytic Bacteria from the Ethnomedicinal Mussaenda roxburghii (Akshap) of Eastern Himalayan Province, India

“…The medium was buffered with HCl to set the desired pH values. The endophytic bacterial isolates were screened for tolerance to heavy metals, namely, Al +3 and Mn +2 , according to the modified method of Konate et al [16]. The tolerance of isolates to Al +3 and Mn +2 was determined on solid YEM medium.…”