Isolasi dan Karakterisasi Gen Pto Asal 20 Aksesi Anggrek Phalaenopsis

Bacterial soft rot disease because of Dickeya sp. infection is the main problem in Phalaenopsis production in Indonesia, but the percentage of infected plants has never been recorded in detail. Isolation and characterization of Pto gene from Phalaenopsis could be useful to support breeding for resistance Phalaenopsis. Encoding serine-threonine kinase, Pto gene confers resistance to bacterial infection of Pseudomonas syringae in tomato. The objectives of this study were to isolate, sequence and characterize fragment of Pto gene from 20 genotypes of Phalaenopsis (16 species and 4 hybrids) and to evaluate their molecular diversity. Genomic fragments of Phalaenopsis were amplified using Pto specific degenerate primers; and the PCR amplicons were sequenced. Searching the identity of determined sequences was done using BLAST against all accessions in NCBI GenBank DNA database and in Conserve Domain Database. PCR amplification using Pto specific primers produced a single DNA fragment of ~500 bp. The determined nucleotide sequences from the amplicon were ~449 bp. The nucleotide sequences of the amplicons from 20 Phalaenopsis genotypes showed high sequence identity to Pto from Musa acuminata. Translation of the amplicon results in ~149 amino acid residues. Comparison of the translated polypeptides identify indicated there were low variations of Pto gene among accessions since they contain the PTO catalytic domain and the Serine/Threonine kinases, sub family of Interleukin-1 Receptor Associated Kinase (STK_IRAK) which are the conserved domains for PTO

Uji Ketahanan Anggrek Hibrida Phalaenopsis terhadap Penyakit Busuk Lunak yang Disebabkan oleh Dickeya Dadantii

One of the most popular orchids and cultivated by Indonesia and other countries is Phalaenopsis. The main disease of Phalaenopsis orchids in Indonesia is soft rot caused by bacteria Dickeya dadantii. The purpose of this study was to know the resistanctcy of Phalaenopsis hybrid to soft rot disease. The experiment was conducted at the Bacterial Plant Laboratory, Department of Plant Protection, the Greenhouse of Leuwikopo, Bogor Agricultural University, and the plastic house of Alam Sinar Sari Dramaga, Bogor from June 2014 to February 2015. The experimental design was randomized block design with three replications. Five genotypes of hybrid Phalaenopsis were tested, namely Phal. KHM 205, Phal. KHM 1126, Phal. KHM 1318, Phal. AMP 17, and Phal. KHM 2249. Phal. amabilis, Phal. esmeralda, Phal. amboinensis, and Phal. cornu-cervi were used as controls. The resistance testing was performed by inoculating bacteria D. dadantii on leaves of the orchids. The results showed all Phalaenopsis hybrid showed disease symptoms after inoculation. Phal. KHM 2249 had the lowest number of fallen leaves and the highest number of survive plants compared to the other hybrid Phalaenopsis. Survival rate was likely related to peroxidase activity and leaf thickness