Ameliorative symbiosis of endophyte (Penicillium funiculosum LHL06) under salt stress elevated plant growth of Glycine max L.
ABSTRACT Experiments were conducted to investigate the role of a newly isolated endophytic fungus GMC-2A on physiology of host plant (Glycine max. L cv. Hwangkeum-kong) growing under salinity stress. GMC-2A was identified as a new strain of Penicillium funiculosum on the basis of sequence homology and phylogenetic analysis of D1/D2 regions of 28S rDNA. Preliminary screening experiment showed that the culture filtrate (CF) of GMC-2A promoted the growth of Waito-C, a dwarf gibberellin (GA) biosynthesis mutant rice cultivar. Analysis of fungal CF revealed the presence of GAs (GA₁ 1.53 ng/ml; GA₄ 9.34 ng/ml; GA₈ 1.21 ng/ml; GA₉ 37.87 ng/ml) and indole acetic acid (14.85 μg/ml). GMC-2A also showed high phosphate solubilization of tricalcium phosphate. Besides that, GMC-2A application enhanced soybean seed germination as compared to control. Under salinity stress (70 and 140 mM), GMC-2A significantly promoted the soybean growth attributes (shoot length, shoot fresh/dry biomass, chlorophyll content, photosynthesis rate and leaf area) in comparison to control treatments. We also observed low endogenous abscisic acid and elevated jasmonic acid contents in GMC-2A treated plants under salt stress. GMC-2A treatment significantly enhanced levels of isoflavones (34.22% and 75.37%) under salinity stress as compared to control. In conclusion, P. funiculosum LHL06 has significantly ameliorated the adverse effects of salinity induced abiotic stress, and re-programmed soybean to higher growth and isoflavone biosynthesis.
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ABSTRACT: Soybean seeds have high amount of isoflavones but its germination is often confronted with a variety of environmental problems resulting in low germination rate and growth. To overcome this in eco-friendly manner, we investigated the influence of cultural filtrate (CF) of gibberellins-producing endophytic fungi on soybean seed germination. Three endophytic fungi namely: Chrysosporium pseudomerdarium, Aspergillus fumigatus and Paecilomyces sp. were previously isolated from the roots of soybean plants. The culture filtrate application of the three endophyte resulted in significantly higher rate of soybean seed germination, germination percentage, relative seed germination percentage, peak value, germination value, shoot and root length, germination index and vigour index. Among the endophytes, A. fumigatus significantly increased the rate of germination, shoot and root length and vigour index. Same trend was noted in germination percentage and relative seed germination percentage for all the endophytic fungi. However, C. pseudomerdarium was the only one that enhanced germination index. The enhanced soybean seed germination by endophytes can be used for seed priming and hence improved crop plant growth under extreme environmental conditions.AFRICAN JOURNAL OF BIOTECHNOLOGY 11/2012; 11:15135-15143. · 0.57 Impact Factor
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ABSTRACT: Background: Endophytic fungi are little known for exogenous secretion of phytohormones and mitigation of salinity stress, which is a major limiting factor for agriculture production worldwide. Current study was designed to isolate phytohormone producing endophytic fungus from the roots of cucumber plant and identify its role in plant growth and stress tolerance under saline conditions. Results: We isolated nine endophytic fungi from the roots of cucumber plant and screened their culture filtrates (CF) on gibberellins (GAs) deficient mutant rice cultivar Waito-C and normal GAs biosynthesis rice cultivar Dongjin-byeo. The CF of a fungal isolate CSH-6H significantly increased the growth of Waito-C and Dongjin-byeo seedlings as compared to control. Analysis of the CF showed presence of GAs (GA 1 , GA 3 , GA 4 , GA 8 , GA 9 , GA 12 , GA 20 and GA 24) and indole acetic acid. The endophyte CSH-6H was identified as a strain of Paecilomyces formosus LHL10 on the basis of phylogenetic analysis of ITS sequence similarity. Under salinity stress, P. formosus inoculation significantly enhanced cucumber shoot length and allied growth characteristics as compared to non-inoculated control plants. The hypha of P. formosus was also observed in the cortical and pericycle regions of the host-plant roots and was successfully re-isolated using PCR techniques. P. formosus association counteracted the adverse effects of salinity by accumulating proline and antioxidants and maintaining plant water potential. Thus the electrolytic leakage and membrane damage to the cucumber plants was reduced in the association of endophyte. Reduced content of stress responsive abscisic acid suggest lesser stress convened to endophyte-associated plants. On contrary, elevated endogenous GAs (GA 3 , GA 4 , GA 12 and GA 20) contents in endophyte-associated cucumber plants evidenced salinity stress modulation. Conclusion: The results reveal that mutualistic interactions of phytohormones secreting endophytic fungi can ameliorate host plant growth and alleviate adverse effects of salt stress. Such fungal strain could be used for further field trials to improve agricultural productivity under saline conditions.BMC Microbiology 02/2012; · 3.10 Impact Factor