INSECT - BANANA PLANT CHEMICAL INTERACTION DURING THE TRANSMISSION OF BANANA BLOOD DISEASE (BBD)

• Main Author: Masriany
• Format: Dissertations
• Language: Indonesia
• Subjects: Ilmu hayati ; Biologi
• Online Access: https://digilib.itb.ac.id/gdl/view/32970
• Institution: Institut Teknologi Bandung

Banana Blood disease (BBD) is one of the important diseases that infect banana plants in Indonesia. It is caused by Blood disease bacterium (BDB) which isthe strain of phylotype IV of Ralstonia solanacearum. Symptoms of BBD are weakening of leaf midribs, yellowing leaves, reddish discoloration of the fruit and pseudo-stem tissue, and male flowers darkening. BBD attacks banana plant systemically and caused death. The wide-range transmission of the disease is due to foraging activity of banana flower insect from the BDB-infected plants to the healthy plants. This study was conducted to investigate chemical interaction between banana plant metabolites and insect vectors of BDB. There were three stages performed during this research. The first stage was to identify the insects daily activity and diversity on the: (1). Flowers of Nangka and Klutuk cultivars; (2). Flowers with and without the BDB symptoms.The effect of abiotic factors to the diversity of banana flower insects was also investigated during this stage . The second stage was to analyze the chemical interaction between the insect vector of BDB with the attractant and phagostimulant metabolites of banana flower. During this stage, metabolomic analysis of sugar and attractant metabolites of Nangka and Klutuk flowers was performed as well as the preference test of banana flower insects Drosophila melanogaster, Rhodesiella bhutanensis, Musca domestica on the standard metabolites of banana flowers. The third stage was to confirm that the insect banana flowers are BDB vectors. The BDB bacteria was isolated and identified from the insects followed by the postulate Koch test to confirm the BDB disease. It was shown that many banana flower insects are active mainly in the morning and in the afternoon. The insect diversity in Nangka cultivar was different significantly from the Klutuk cultivar with significance of F(1,3)= 1,035 (p < 0.001). There are four genera of insects found in Nangka cultivar: Diptera, Hymenoptera, Coleoptera, Blattodea, with 11 species: Rhodesiella bhutanensis, R. manii, ants, Eupuraea sp, Tribolium sp, Choragus sp, Carpophylus sp, Vespa sp, D. melanogaster., Blatella sp, M. domestica, whereas in Klutuk, only four species were found: R. bhutanensis, ants, Choragus sp, Eupuraea sp. The D. melanogaster, Carpophylus sp., and M. domestica are highly abundant in the BDB infected flowers., whereas the R. bhutanensis, Vespa sp., and ants are highly abundant in the health flowers. Abiotic factors such as temperature, pH, humidity, and light intensity are suggested to influence the insect diversity. Metabolomic analysis has shown that the monoterpene attractant metabolite was different significantly within the flower of Nangka and Klutuk cultivars. Similarly, the amount of ?-pinene metabolites in BDB-infected flowers was higher compared to the uninfected flowers. The ?-pinene metabolite is known to be dominant in the flower of Nangka cultivar and is suspected to be an attractant for banana insect pollinators. Glucose and fructose are sugar metabolites that was found significantly different qualitatively and quantitatively in the BBD-infected and healthy flowers . In addition, preference tests have shown that insects were more attracted to ?-pinene than methanol and prefer glucose over fructose or sucrose. In conclusion, for D.melanogaster, R. bhutanensis, and M. domestica insects, ?-pinene and glucose are the attractant and phagostimulant metabolites of banana flowers. . Identification of the isolated bacteria from the insect vectors morphologically, biochemically, and molecularly has shown that the isolate was gram negative bacteria with similar characteristics with the R. solanacearum BDB strain. The result was confirmed by Koch's postulate test that showed discoloration/yellowing and wilting of the banana plants. R. bhutanensis and D.melanogaster contained most of the BDB bacteria, leading these insects to be potential BDB vectors via their feeding activities on banana flowers. Chemical interaction between BDB insect vectors and banana flowers is suggested via the ?-pinene metabolite that is released by the banana flowers which attract the D.melanogaster and R. bhutanensis insects. Both insects then performed foraging activity on the banana flowers stimulated by glucose. The spreading of BDB disease is suggested due to foraging activity performed by these insects from BDB-infected plants to the healthy plants on banana flowers hurt BBD, the bacteria that are present in the flowers may be carried along either into the body tissues or outside the body of the insect, and then the bacteria migrate when the insects move to other banana plants so that there was a spread of BDB from one banana plant to another.