Phenotypic diversity and amylolytic activity of fast growing rhizobia from pigeonpea [Cajanus cajan (L.) Millsp.]

Abstract

This study evaluated 26 pigeonpea rhizobial isolates according to their cultural characteristics, intrinsic antibiotic resistance, salt and temperature tolerance, carbon source utilization and amylolytic activity. The cultural characterization showed that the majority of them presented the ability to acidify the YMA. Among the 27 isolates evaluated, 25 were able to grow when incubated at 42° C and 11 showed tolerance to 3% (w/v) of NaCl in YMA medium. The patterns of carbon sources utilization was very diverse among the isolates. It was observed the capacity of three strains to metabolize all the carbon sources evaluated and a total of 42% of the bacterial isolates was able to grow in the culture medium supplemented with at least, six carbon sources. The carbon sources mannitol (control) and sucrose were metabilized by all isolates evaluated. The profile of intrinsic resistance to antibiotics showed that the isolates were mostly resistant to streptomycin and ampicillin, but susceptible to kanamycin and chloranphenicol. High amylolytic activity of, at least, four isolates was also demonstrated, especially for isolated 47.3b, which showed the highest enzymatic index. These results indicate the metabolic versatility of the pigeonpea rhizobia, and indicates the isolate 47.3b to further studies regarding the amylase production and characterization.

The Resurrection Plant Tripogon Spicatus (Poaceae) Harbors a Diversity of Plant Growth Promoting Bacteria in Northeastern Brazilian Caatinga

“…Combining all physiological results, the data suggest that the isolates are able to persist in the soil or in the desiccated tissues of t. spicatus due to their tolerance to harsh environments and metabolic versatility in regard to the ability to metabolize different C sources and tolerance to antibiotics that may be produced by other soil micro-organisms (Fernandes Júnior et al, 2012b;Jha et al, 2012).…”

Phenotypic and molecular fingerprinting of fast growing rhizobia of field-grown pigeonpea from the eastern edge of the Brazilian Pantanal

“…In spite of the great number of isolates that presented high or intermediate resistance to chloramphenicol (17 isolates in all), this is a very uncommon characteristic for pigeonpea nodulating rhizobia (Anand and Dogra, 1991;Fernandes et al, 2003;Fernandes Jr. et al, 2012). The isolates also showed a generally low IAR for kanamycin, which is a very common characteristic for tropical rhizobia.…”

“…The slow and fast growing pigeonpea rhizobia present great genetic and metabolic diversity and are likely to have new species among the culture collections worldwide (Ramsubhag et al, 2002;Fernandes Jr. et al, 2012). In addition to being efficient in fixing nitrogen in field conditions, pigeonpea rhizobia also present other biotechnological applications, such as biopolymer production and enzymatic activity (Fernandes Jr. et al, 2010.…”

Morphophysiological diversity of rhizobia nodulating pigeon pea (Cajanus cajan L. Millsp.) growing in Ethiopia

“…To exploit the biological nitrogen fixation (BNF) potential of this crop, the selection and evaluation of new rhizobial strains from different areas where pigeon pea is cropped must be carried out. The slow and fast growing pigeon pea rhizobia present great genetic and metabolic diversity and are likely to have new species among the culture collections worldwide (Fernandes et al, 2012;Ramsubhag et al, 2002). In addition to being efficient in fixing nitrogen in field conditions, pigeon pea rhizobia also present other biotechnological applications, such as biopolymer production and enzymatic activity (Fernandes et al, 2012;Júnior et al, 2011).…”

“…The slow and fast growing pigeon pea rhizobia present great genetic and metabolic diversity and are likely to have new species among the culture collections worldwide (Fernandes et al, 2012;Ramsubhag et al, 2002). In addition to being efficient in fixing nitrogen in field conditions, pigeon pea rhizobia also present other biotechnological applications, such as biopolymer production and enzymatic activity (Fernandes et al, 2012;Júnior et al, 2011). Nevertheless, it should be noted that for Ethiopia, information is scarce about indigenous rhizobia that nodulate grain legumes such as pigeon pea.…”