Agricultural Sciences in China 2010, 9(8): 101-105 August 2010 © 2010, CAAS. All rights reserved. Published by Elsevier Ltd. doi: Induction of Tolerance to Fusarium Wilt and Defense-Related Mechanisms in the Plantlets of Susceptible Berangan Banana Pre-Inoculated with Pseudomonas sp. (UPMP3) and Burkholderia sp. (UPMB3) Elya Masya Mohd Fishal, Sariah Meon and Wong Mui Yun Laboratory of Food Crops and Floriculture, Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, D.E., Malaysia Abstract This study is aimed at assessing the ability of two endophytic bacteria originally isolated from healthy oil palm roots, Pseudomonas sp (UPMP3) and Burkholderia sp (UPMB3) to induce resistance in susceptible Berangan banana against Fusarium oxysporum race 4 (FocR4). Increased accumulation of resistance-related enzymes such as peroxidase (PO), phenylalanine ammonia lyase (PAL), lignithioglycolic acid (LTGA) and pathogenesis-related (PR) proteins (chitinase and β-1, 3-glucanase) has been observed in plantlets treated with endophytic bacteria UPMP3 and UPMB3 singly or as mixture under glasshouse conditions. Pre-inoculation of banana plantlets with UPMP3 showed a significant reduction in Fusarium wilt incidence 72 days after challenged inoculation with FocR4. UPMB3 was less effective in suppressing Fusarium wilt compared to UPMP3, whereas, the mixture of both endophytes showed an intermediate effect. Based on these results, it is concluded that UPMP3 could be a promising biological control agent that can trigger resistance against Fusarium wilt in susceptible Berangan banana. Key words: banana, Pseudomonas sp., Burkholderia sp., induce resistance, Fusarium wilt INTRODUCTION Banana production world-wide is under severe threat due to fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) (Ploetz et al . 2003). Fusarium wilt has destroyed thousand hectares of Cavendish bananas in many tropical countries including Indo- nesia and Malaysia (Hwang and Ko 2004). Once established in an area, Fusarium cannot be controlled chemically or through cultural practices, thus the only long-term option for continuing banana production is replacement of a susceptible variety with a resis- tant one (Hwang and Ko 2004). Since the control of Fusarium wilt is limited by ineffectiveness of chemi- cal methods and lack of commercially suitable resis- tant cultivars, biological control by using endophytic microorganisms is, therefore considered a viable strat- egy to induce resistance in susceptible cultivar for controlling Fusarium wilt. Endophytes offer a wide range of benefits to plants such as promoting growth (Kang et al. 2007), reduc- ing disease severity (Senthilkumar et al. 2007), and in- ducing plant defense mechanisms (Bakker et al. 2007). Recently a lot of researches have been carried out fo- cusing at re-introduction of naturally occurring endo- phytes into banana plantlets before the plants are sold to farmers (Dubois et al. 2006). Effectiveness of endophytes as a biological control agent depends largely on factors including host Received 16 November, 2009 Accepted 11 February, 2010 Elya Masya Mohd Fishal, MSc, Tel: +60-1250-66292, E-mail: masya_brywest@hotmail.com; Correspondence Sariah Meon, Professor, Tel:+60-3894-68966, Fax: +60- 3894-68968, E-mail: sariahm@putra.upm.edu.my