Disease resistance breeding of Phalaenopsis spp. for tropical environment and molecular marker development for plant selection
Phalaenopsis is one of the most important ornamental plants in Indonesia and the market demand for this ornamental crop tended to increase in the last five years. One constraint in Phalaenopsis cultures under tropical environment is soft rot disease caused by Dickeya dadantii infection, which spreads quickly because of the humid and warm environments. Therefore, development of disease resistant Phalaenopsis cultivars would be beneficial under tropical environment. Series of research activities have been developed to achieve the objectives. Resistance of various Phalaenopsis species against D. dadantii was evaluated. Moreover, molecular analysis for disease resistance and disease responsive genes (i.e., Pto and Chitinase [Chi]) have been evaluated for their nucleotide sequence diversity and were used to develop SNP based molecular markers for resistance screening of Phalaenopsis genotypes. Results of the evaluation indicated that most of the Phalaenopsis species and hybrids were susceptible to D. dadantii infection. However, a limited number of Phalaenopsis species are at least moderately resistant; for example, Phal. amboinensis and Phal. pantherina. Hybridization among resistant and susceptible Phalaenopsis species and their hybrids have been initiated. The Pto and Chi genes from resistant and suceptible genotypes have been isolated and their nucleotide diversity evaluated. A number of single nucleotide polymorphisms (SNPs) exist among the Pto and Chi genes. SNP specific primer pairs have been developed and used to generate SNAP markers. The developed SNAP markers are effective for genetic diversity analysis and predicting the resistance responses against D. dadantii of Phalaenopsis species and their hybrids. Comprehensive results of the evaluations were presented.
Sukma, D. and Elina, J. 2017. Disease resistance breeding of Phalaenopsis spp. for tropical environment and molecular marker development for plant selection. Acta Hort. (ISHS) 1167:237-244
Phalaenopsis species, resistance breeding, molecular markers, Pto gene, Chi gene, SNAP markers