Mapping and Molecular Detection of Banana Fusarium Wilt in South Sulawesi Using Volatile Odor Test and Race-Specific PCR Primers

Abstract

Fusarium wilt of bananas, caused by Fusarium oxysporum f. sp. cubense (Foc), poses a serious threat to banana cultivation, particularly with the emergence of physiological race 4. This study mapped the prevalence of Fusarium wilt in 16 governorates/cities of South Sulawesi Province (2020-2024) and identified physiological race 4 of Foc at various growth stages using odor detection (VOT) and PCR detection methods. Spatial and temporal analyses of regional disease prevalence were conducted at three sites (60-600 plants) in the Palangloe district of Gowa Regency. Samples were collected from symptomatic plants, inoculated onto PDA medium containing 500 ppm streptomycin, isolated on PDA, purified, and morphologically identified. The odor test was performed using a rice medium containing aldehyde odor indicators. DNA was extracted from meristem/apical and pseudostem/venous tissues and amplified using the primers FocEf3 (General Foc), SIX10a (Race 4), SIX13c (Race 4), and SIX1a (TR4) and visualized on a 2% agarose gel. Most areas exhibited very low infestation rates. Investigations revealed significant differences in infestation rates between different planting sites (p<0.001), with the highest infestation rate (18.33%) in the Barangan cultivar of the Bellapunranga region and the lowest (0%) in the Raja/Kepok cultivar of the Borissalo Region. The aldehyde aroma produced by the isolates under VOT conditions was consistent with that of Foc Race 4. PCR results showed that the primer SIX1a_266 confirmed the presence of TR4 in two Cavendish samples from Bantokassi, highlighting the importance of interlayer monitoring and early stage seedling screening.