Characterization of Fusarium spp. Associated to Fusarium Wilt Symptom on Piper nigrum L. in North-western Region of Sarawak
Fusarium wilt is one of the major diseases in Sarawak pepper plantation. Fusarium spp. had been identified as the causal agent for the disease. Hence, further understanding on the causal agent, Fusarium spp. is essential in the initial step to design a sustainable disease control strategies such...
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| Format: | Thesis |
| Language: | English |
| Published: |
University Malaysia Sarawak
2023
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| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/41856/3/Tan%20Wan%20Joo.pdf http://ir.unimas.my/id/eprint/41856/ |
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| Summary: | Fusarium wilt is one of the major diseases in Sarawak pepper plantation. Fusarium spp. had
been identified as the causal agent for the disease. Hence, further understanding on the causal
agent, Fusarium spp. is essential in the initial step to design a sustainable disease control
strategies such as development of disease resistance varieties to curb the disease. The
objectives for this study were: 1. To isolate and characterise morphologically and
molecularly Fusarium species associated with Fusarium wilt of Piper nigrum L.. 2. To study
the growth performance of Fusarium solani isolates on different pH and nutrient media. 3.
To study the genetic relatedness of Fusarium solani isolated in Malaysia as well as those
across Asia. Ten F. solani, three Fusarium oxysporum and eleven Fusarium proliferatum
were isolated from diseased root samples collected from fifteen pepper farms in Northwestern region of Sarawak and identified based on Internal Transcribed Spacer (ITS)
sequence. Variations were found on the colony morphology, growth, sporulation rate and
ITS sequence of the Fusarium spp. isolates. The isolates also showed morphological
variations within each species. Nine isolates of F. solani were further characterised for their
colony morphology and growth on Potato dextrose agar at pH 5-9. Their morphology and
growth were also recorded on five different types of nutrient media. The isolates displayed
variation of colony morphology across the pH and showed better growth performance when
cultured under pH 7-8 compared to other pH of PDA media. F. solani isolates also portrayed
variations in colony morphology when cultured on different nutrient media. Isolates cultured
on PDA media showed the most colony variations in terms of morphological appearance.
Five out of nine isolates were more favourable to grow on Carnation Leaf Agar media. ITS
sequence ranged from 517 bp to 525 bp was used for genetic relatedness study. It was found
that F. oxysporum and F. proliferatum isolates are genetically closer with each other as they
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shared the same common recent ancestor. Both the phylogenetic analysis of local Fusarium
isolates and F. solani isolates from Asia region highlighted their genetical relationship was
not based on the geographical distribution of the isolates. Besides that, the analysis showed
similarity of colony appearance of the isolates also does not related with their genetical
relationship. In conclusion, the objectives of this study were achieved where three Fusarium
spp. associated to Fusarium wilt of Piper nigrum L. were successfully isolated. The colony
morphological variations of all the isolates were studied and documented. Different pH and
nutrient media were found to affect the colony appearance and growth performance of the
F. solani isolates. Genetic relatedness of the isolates were found to be not related to their
geological distribution.
Keywords: Fusarium spp., Piper nigrum L, morphological characterisation, growth,
genetic relatedness |
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