Title Symbiotic Interaction of Endophytic Bacteria with Arbuscular Mycorrhizal Fungi and Its Antagonistic Effect on Ganoderma boninense
Author Shamala Sundram1,2*, Sariah Meon1, Idris Abu Seman2, and Radziah Othman1
Address 1Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia, 2No 6, Persiaran Institusi, Bdr Baru Bangi, 43000 Kajang, Selangor, Malaysia
Bibliography Journal of Microbiology, 49(4),551-557, 2011,
DOI
Key Words arbuscular mycorrhizal fungi, endophytic bacteria, Ganoderma boninense, Elaeis guineensis
Abstract Endophytic bacteria (Pseudomonas aeruginosa UPMP3 and Burkholderia cepacia UPMB3), isolated from within roots of oil palm (Elaeis guineensis Jacq.), were tested for their presymbiotic effects on two arbuscular mycorrhizal fungi, (Glomus intraradices UT126 and Glomus clarum BR152B). These endophytic bacteria were also tested for antagonistic effects on Ganoderma boninense PER 71, a white wood rot fungal pathogen that causes a serious disease in oil palm. Spore germination and hyphal length of each arbuscular mycorrhizal fungal (AMF) pairing with endophytic bacteria was found to be significantly higher than spores plated in the absence of bacteria. Scanning electron microscopy (SEM) showed that the endophytic bacteria were scattered, resting or embedded on the surface hyaline layer or on the degraded walls of AMF spores, possibly feeding on the outer hyaline spore wall. The antagonistic effect of the endophytic bacteria was expressed as severe morphological abnormalities in the hyphal structures of G. boninense PER 71. The effects of the endophytic bacteria on G. boninense PER 71 hyphal structures were observed clearly under SEM. Severe inter-twisting, distortion, lysis and shrivelling of the hyphal structures were observed. This study found that the effect of endophytic bacteria on G. intraradices UT126 and G. clarum BR152B resembled that of a mycorrhiza helper bacteria (MHB) association because the association significantly promoted AMF spore germination and hyphal length. However, the endophytic bacteria were extremely damaging to G. boninense PER 71.