STUDY ON SENGON (Falcataria moluccana) RESISTANCE TO BOKTOR PEST (Xystrocera festiva) AND GALL RUST (Uromycladium tepperianum)
U.J.Siregar, S.Hartati

Source: SEAMEO BIOTROP's Research Grant | 2021




a.             Analysis of gene expression related to boktor pest resistance and tumor rust using RT-PCR

b.             Development of SNIP markers for Genome-wide association selection (GWAS) on the resistance properties of boktor pests and tumor rust

c.             Identification of Open Reading Frames (ORFs) from transcriptomic sequence analysis and Blastx.

Expected Output

a.             Optimization of the protocol for the expression of multiple gene sequences using RT-PCR

b.             New SNIP markers for selection of resistance properties related to boktor pests and tumor rust

c.             The full length of the expressed genes, especially those related to the resistance of sengon to tumor rust and boktor pestsIdentification of Open Reading Frames (ORFs) from transcriptomic analyses and BLASTX



The RT-PCR results for the TI4 gene and the Actin 1 gene were good with the formation of a tight amplification curve and the melting curve only produced one peak. The electrophoresis results of TI4 and Actin 1 genes also produced a single band, which means the sample has good quality. CT value in the TI4 gene ranged from 24.33 to 26.99, while the CT value of Actin 1 gene ranged from 22.36 to 24.69. Quantification using 2-ΔΔCT method shows the level of TI4 gene expression in sengon samples healthy (S) that is equal to 1.00 while in the sample attacked by boktor (B) of 1.91. TI4 gene expression in sengon attacked by boktor pests was higher than in healthy sengon.

Identification of gene encoding α-Amylase enzyme in plants Falcataria moluccana Miq, which was attacked by boktor pests, was successfully carried out. RT-PC on Falcataria moluccana amplified at temperature annealing 57 °C for Actin 1 and 61°C for the AAI gene. The average CT value of the Actin 1 gene that was attacked by boktor pests was 24.50 and those that were not attacked by boktor pests was 23.51. While the average CT value in the AAI 2 gene that was attacked by boktor pests was 29.18 and those that were not attacked by boktor pests was 29.67. The value of 2^(-∆∆Ct) on trees that were attacked by boktor pests had a higher value of 2.80 than those that were not attacked by boktor pests of 1.00.

The expression of tumor rust-associated genes varies. In seedlings treated with infection, there were genes whose expression increased after infection was induced and there were genes that decreased expression after infection. Meanwhile, in mature plants, the average expression of all genes was higher in tumors than in healthy wood and wood around the tumor. The higher expression of certain genes in the wood around the tumor than in healthy wood indicated that there was an indication that the gene was induced by infection with pathogens in the tumor tissue.

Sequence of the sengon reference genome de novo using Ray assembler showed better genome coverage than the two assembler other. Results assembly from SOAPd enovo and Ray showed low genome completeness due to the large number of missing BUSCO genes (>70%). The annotation results show that there are two sequences containing the AAI gene and 19 sequences containing the TI gene assembly which has been done.



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