Endophytic fungal association via gibberellins and indole acetic acid can improve plant growth under abiotic stress: an example of Paecilomyces formosus LHL10

BMC Microbiology

Research Article

Muhammad Hamayun¹  Joong-Hwan Lee²  Hee-Young Jung³  Sang-Mo Kang⁴  Yoon-Ha Kim⁴  In-Jung Lee⁴  Abdul Latif Khan⁵ 

[1] Department of Botany, Abdul Wali Khan University, Mardan, Pakistan;Division of Agriculture Environment Research, Gyeongsangbuk- Do Agricultural Research and Extension Services, Daegu, Republic of Korea;Division of Applied Biology and Chemistry, College of Agriculture and Life Sciences, Kyungpook National University, Daegu, Republic of Korea;School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea;School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea;Department of Plant Sciences, Kohat University of Science & Technology, Kohat, Pakistan;

关键词: Paecilomyces formosus;    Salinity;    Cucumber plant growth;    Gibberellins and indole acetic acid;    Endogenous plant hormones;   

DOI  :  10.1186/1471-2180-12-3

 received in 2011-07-29, accepted in 2012-01-12,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundEndophytic 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.ResultsWe 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 (GA1, GA3, GA4, GA8, GA9, GA12, GA20 and GA24) 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 (GA3, GA4, GA12 and GA20) contents in endophyte-associated cucumber plants evidenced salinity stress modulation.ConclusionThe 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.

【 授权许可】

Unknown   
© Khan et al; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.