Isolation and characterization of endophytic bacteria from endorhizosphere of sugarcane and ryegrass
M Gangwar, G Kaur
bacterial diversity, diazotroph, endophyte, endorhizosphere, pgpr
M Gangwar, G Kaur. Isolation and characterization of endophytic bacteria from endorhizosphere of sugarcane and ryegrass. The Internet Journal of Microbiology. 2008 Volume 7 Number 1.
The present study was conducted with a view to isolate and characterize endophytic bacterial diversity from endorhizosphere of sugarcane (
Endophytes are of agronomic interest as they can enhance plant growth in non-leguminous crops and improve their nutrition through nitrogen fixation (Boddey
Thus, study was conducted with a view to isolate endophytic bacteria and to asses functional potentialities in relation to plant growth promoting activities i.e. IAA, phosphate solubilizer, nitrogenase activity and siderophore production. These can be recommended as bioinoculants for non-leguminous crops, which can help to reduce dependence on chemical fertilizers and provide a step forward towards sustainable agriculture.
Materials And Methods
Sugarcane and ryegrass root samples (eight each) were collected from different areas of Ludhiana i.e Jagraon, Gujjarwal, Laddowal, Samrala and Punjab Agricultural University. Isolation of bacterial diversity was done by using Reis method (Reis
Results And Discussion
Morphological and biochemical characterization
Eight isolates from sugarcane (S1-S8) and seven isolates from ryegrass (R1-R7) were obtained from endorhizosphere of both the crops. The growth of cultures S3, S4 (sugarcane) and R1, R2 (rye grass) on respective media was recorded to be circular and transparent in colour. Morphologically, the cells appeared to be gram negative, motile vibroids. Sugarcane (S1) and rye grass isolate (R6) exhibited formation of yellow colored irregular colonies and cells were motile, gram negative rods as observed under microscope. Lindberg and Granhall (1984) reported similar morphological characteristics in dinitrogen fixing bacteria from rhizosphere of temperate cereals and forage grasses.
Another kind of cultural characters were also observed for (S2) sugarcane and (R7) ryegrass isolates that appeared to have greyish white irregular colonies and morphologically were gram positive motile coccobacilli. (Table 1) These findings are similar to morphological characteristics of
Three sugarcane isolates S4, S7 and S8 and four ryegrass isolates R1, R2, R6 and R7 showed acid production in sugar fermentation broth supplemented with mannitol which indicates mannitol utilization as carbon source (Table2). Isolate S3 (sugarcane) and isolates R1, R2, R3, R4 (ryegrass) were able to utilize lactose. Galactose was utilized by sugarcane isolates (S5, S6) and ryegrass isolates (R1, R2, R3). Two ryegrass isolates i.e. R1 and R2 and two sugarcane isolates S2 and S3 were able to utilize xylose, which is a ketopentose. Majority of isolates among sugarcane isolates (S1, S2, S3, S5, S7) and ryegrass (R1, R3, R5, R6, R7) were able to utilize glucose indicating glucose to be a preferred carbon source. Lindberg and Granhall (1984) reported that
Antibiotic resistance spectra
All sugarcane isolates were sensitive to gentamycin, amikacin and streptomycin. Isolate S5 (
Out of all fifteen isolates only sugarcane isolate S6 (
Nitrogen fixation ability (ARA)
The range of nitrogenase ativity in case of sugarcane isolates was 217.3 -1221.0 nM C2H4h -1 g -1 protein with maximum value recorded by isolate S3 (
All the isolates produced siderophore in range of 0.7-3.0 mg l -1 . Out of eight isolates of sugarcane only six were observed to produce siderophore. S6 isolate (
Indole acetic acid production (IAA)
All the isolates were observed to produce the phytohormone IAA, which ranged from 4-19.3 g ml -1 among sugarcane isolates. Isolate S5 (
The isolates were identified as