Characterization of Trichoderma isolates from Philippine rice fields by UP-PCR and rDNA-ITS1 analysis:: Identification of UP-PCR markers

Forty-two isolates of Trichoderma from rice fields in four provinces in the Philippines were characterized using rDNA-ITS1 analysis and universally primed polymerase chain reaction (UP-PCR). Two groups were clearly distinguishable on the basis of length and restriction pattern of the internal transcribed spacer (ITS) region of the ribosomal DNA and UP-PCR banding profiles using UP primer, L45. The 40 isolates comprising the largest group were very similar with respect to their UP-PCR banding profiles and were assigned to Trichoderma harzianum Rifai following morphological identification of four of the isolates. The two isolates belonging to the second group were identified as Trichoderma viride Pers. ex. Gray on the basis of their morphology, rDNA-ITS1 analysis and distinct UP-PCR banding profiles. One of the T. harzianum isolates with good cellulolytic and competitive saprophytic abilities was analysed using single and pairwise combinations of UP primers in order to distinguish it from the remaining 41 isolates. A suitable diagnostic marker was identified and this marker will be valuable for monitoring the isolate in field tests.