22 Endophytes have also been shown to influence photosynthesis rate in host
plants as seen in tall fescue plants infected by N. coenophialum photosynthesised faster and flowered earlier than the non-infected ones Newman et al. 2003, also
endophyte infected tall fescue plants exhibited higher survival and flowering frequency Hill et al. 1991. Such attributes of endophyte infection confer an
ecological advantage to the endophyte infected plants, enabling their survival and dorminance over endophyte free plants.
2.13.3 Induced resistance: Induction of systemic resistance by non-
pathogenic microorganisms against pests and diseases is well documented phenomenon Rammamorthy et al. 2001; Compant 2005a. For example non-
pathogenic F. oxysporum isolates induced resistance in tomato plants to F. oxysporum
f.sp. lycopersici Jarvis et Shoem, when inoculated prior to infection by the pathogen. Induced systemic resistance ISR can be defined as the
resistance in plants induced by localized infection or treatment with microbial components
or their
products, or
chemicals compounds
Rammamorthy et al. 2001. ISR can be differed from systemic acquired resistance SAR. SAR develops in plants in response to both biotic pathogen
attack and abiotic factors Chemicals and depends on the accumulation of the salicylic acid Van Loon et al. 1998, the onset of SAR is characterized by the
expression of the genes for the PR-proteins such as PR-1, PR-2, Chitinase and peroxidase M’Piga et al. 1987; Rammamorthy et al. 2001; Jeun et al. 2004.
ISR on the other hand is dependent on the jasmonic acid and phenylpropanoid pathways Pieterse et al. 1998; Van Loon et al. 1998; Rammamorthy et al.
2001 ISR leads to the synthesis of plant defence products including peroxidases, polyphenol oxidases and phenylalanine ammonia-lyases PAL. Polyphenol
oxydase catalyses the formation of lignin through polymerization of phenols while PAL are involved in synthesis of phytoalexins and phenolic compounds.
2.13.4 Competition : Competition for plant space and resources may occur
between resident endophytes and incoming plant pathogens this could eventually lead to the reduction of various pathogens in plants by the endophytes.
23
III. MATERIALS AND METHODS
3.1 Time and Location of Study
This research was conducted in Nematology Laboratory Department of Plant Protection, Faculty of Agriculture and in greenhouse at Cikabayan, Bogor
Agricultural University, Bogor West Java Province, Indonesia from February to August 2009.
3.2 Exploration of Endophytic Fungi 3.2.1 Isolation and identification of endophytic fungi
Healthy and nematode infected tomato plant samples were collected for isolation of endophytic fungi from tomato plant roots in highland and lowland
areas. The method used for isolation of endophytic fungi was that proposed by Rodrigues 1994 that has already been modified. Tomato plant roots were
washed thoroughly using flowing water to remove all the soil particles from the roots. Sterilization of the root surface was done by dipping the roots in 70
ethanol for one minute, and then to 1 NaOCl for three minutes after which the roots were rinsed three times with sterile water then dried on dry sterile blotting
paper. The roots were then cut into small pieces and placed on petri dishes already filled with PDA under laminar airflow, in each petri dish three root pieces
were placed and replicated three times then incubated at room temperature and observed for a period of one week, after which the fungal colonies that developed
from the cut root tissues were purified on new PDA media and the isolates that developed were tested for their pathogenicity potential then identified based on
colony colour and morphology as well as observation of microscopic features using identification keys according to Watanabe 2002.
3.2.2 Selection of endophytic fungi based on pathogenicity test
To ensure that the isolated endophytic fungi were not pathogenic and produce disease symptoms to the host plants later after inoculation then there was
high need to test for the pathogenicity potential of the isolates to be used, this was
