Articles
Molecular characterization of soft-rot disease pathogen from Phalaenopsis and differences in genotype response to its infection
Article number
1334_14
Pages
111 – 118
Language
English
Abstract
Soft-rot disease (SRD) is found in many horticulture plants including Phalaenopsis. Several bacteria species were reported as the causal agent of SRD. Most Phalaenopsis species and hybrids are susceptible to SRD. Previous studies suggested Phalaenopsis amboinensis is the most resistant to SRD compared to other species of Phalaenopsis including P. amabilis. The goals of this research were to identify the SRD pathogen, observe genotypes resistant variation in the species, and provide progenies from the crossing of resistant and susceptible species for the further resistant breeding program and resistant mechanisms studies to SRD. Screening of the species which have stable resistant responses to SRD pathogen is important in selecting the resistant parents.
We isolated the SRD pathogen from the infected P. amabilis leaf and performed molecular characterization using the 16S rRNA marker gene.
The sequencing data of the bacteria confirmed the isolate as be Dickeya dadantii with 98.37% of sequence identity matching as Dickeya sp. on NCBI. In the next experiment, we tested the responses of 47 P. amboinensis and 29 P. amabilis plants against D. dadantii using the detached leaf inoculation method.
Soft-rot symptom diameter was measured at 6 to 42 h post-inoculation (HPI) for disease assessment.
We found that from 47 P. amboinensis plants, 2.13% are very susceptible, 2.12% are susceptible, 4.25% are moderate resistant, and 91.49% are resistant.
Conversely from 29 P. amabilis plants tested, 20.69% are very susceptible, 3.45% are susceptible, 13.78% are moderately susceptible, and 62.08% are resistant.
We conclude that the resistance trait in P. amboinensis is more stable compared to the P. amabilis. The crossing between resistant plant (P. amboinensis) × susceptible plant (P. amabilis) has been conducted and produced protocorm for further studies.
We isolated the SRD pathogen from the infected P. amabilis leaf and performed molecular characterization using the 16S rRNA marker gene.
The sequencing data of the bacteria confirmed the isolate as be Dickeya dadantii with 98.37% of sequence identity matching as Dickeya sp. on NCBI. In the next experiment, we tested the responses of 47 P. amboinensis and 29 P. amabilis plants against D. dadantii using the detached leaf inoculation method.
Soft-rot symptom diameter was measured at 6 to 42 h post-inoculation (HPI) for disease assessment.
We found that from 47 P. amboinensis plants, 2.13% are very susceptible, 2.12% are susceptible, 4.25% are moderate resistant, and 91.49% are resistant.
Conversely from 29 P. amabilis plants tested, 20.69% are very susceptible, 3.45% are susceptible, 13.78% are moderately susceptible, and 62.08% are resistant.
We conclude that the resistance trait in P. amboinensis is more stable compared to the P. amabilis. The crossing between resistant plant (P. amboinensis) × susceptible plant (P. amabilis) has been conducted and produced protocorm for further studies.
Authors
I.P.W. Sanjaya, S. Sudarsono, M.T. Chan, D. Sukma
Keywords
16S rRNA, breeding, Dickeya dadantii, orchid, resistance, susceptible
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