Molecular characterization of soft-rot disease pathogen from Phalaenopsis and intraspecific response differences to its infection

I Putu Wahyu Sanjaya is currently a second-year PhD student in the Plant Breeding and Biotechnology Study Program at IPB University, Bogor, Indonesia, working on his dissertation entitled “Molecular analysis of Phalaenopsis resistance to soft-rot pathogen (Dickeya dadantii).” He has been working on the Phalaenopsis resistance studies since 2018. He obtained his MSi (Master of Science, Indonesia) degree working on similar topics from the same study program at IPB University. His interest is in molecular biology, plant-pathogen interaction, plant tissue culture, plant physiology, and plant breeding. All of his studies and research were sponsored by the Indonesian Ministry of Research and Technology for Higher Education under the Master Program of Education Leading to Doctoral Degree for Excellent Graduates (PMDSU) supervised by Dr. Dewi Sukma and Prof. Sudarsono from IPB University, and Prof. Ming-Tsair Chan from Academia Sinica Biotechnology Center in Southern Taiwan. Phalaenopsis is an important ornamental plant in Indonesia and in the world. The distribution of Phalenopsis species is mainly in tropical to subtropical areas, which have high temperature and humidity. These plants are easier to grow In Indonesia than in some subtropical areas because only a minimum of environment control is required. Small to medium scale nurseries usually use shading or net houses to grow their Phalaenopsis. Unfortunately, the shading/net house does not protect Phalaenopsis from pathogen infection and pest infestation. One of the most devastating Phalaenopsis diseases in Indonesia is soft-rot disease (SRD). Wahyu screened Phalaenopsis species using Dickeya dadantii, the pathogen that causes SRD. He determined resistance classes. He validated that Phalaenopsis amboinensis is the most resistant species as compared with P. pantherina, P. bellina, P. cornu-cervi, P. mentawaiensis, P. amabilis, and P. schilleriana. He also found higher defense enzyme activities including peroxydase and phenylalanine ammonia-lyase in more susceptible species. He found a varied level of responses to D. dadantii infection within the intraspecific populations of P. amboinensis and P. amabilis. For a population of P. amboinensis, at least 2.1% were either very susceptible or susceptible, 4.3% – moderate resistant, and 91.5% – resistant, while for P. amabilis, 20.7% were very susceptible, 3.5% – susceptible, 13.8% – moderately susceptible, and 62.1% – resistant. The data indicated that Phalaenopsis breeders who want soft-rot resistant plants could screen intra-specific populations of Phalenopsis. Wayhu also obtained progeny arrays for interspecific Phalaenopsis hybrids to study genetic inheritance of soft-rot resistance and evaluate molecular mechanisms associated with that resistance.

I Putu Wahyu Sanjaya won the ISHS Young Minds Award for the best oral presentation at the II International Symposium on Tropical and Subtropical Ornamentals, which was held virtually in Indonesia in July 2021.

I Putu Wahyu Sanjaya, Plant Breeding and Biotechnology Study Program, Department of Agronomy and Horticulture, Faculty of Agriculture, IPB University, Bogor, Indonesia, e-mail: putuw87@ymail.com

The article is available in Chronica Horticulturae