Spatiotemporal distribution of Fusarium oxysporum f. sp. cubense race 1 and race 4 in Brazilian plant and rhizosphere soil

Objective Banana (Musa spp.) is one of the important economic crops in China. However, banana fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) seriously devastates the development of banana industry in China due to the rapid spread and difficult control of this disease. It is important to explore the spatial and temporal distribution of Foc in Brazilian (Musa acuminate L. AAA group, cv. Brazilian) plant and rhizosphere soil, which are directly related to infection and pathogenicity of Foc.

Method Brazilian seedlings were inoculated with race 1 (Foc1) or race 4 (Foc4) by wounding roots in greenhouse, the amount and spatial distribution of Foc in different tissues at different times and in different rhizosphere soil of banana seedlings were analyzed using real-time quantitative PCR.

Result From 2 to 21 days after inoculation, the contents of Foc1 and Foc4 in Brazilian roots and rhizomes increased with time, and the contents of Foc4 were significantly higher than those of Foc1. The contents of Foc1 and Foc4 in Brazilian rhizomes reached the highest at 21 and 14 days after inoculation, respectively. In the field, Foc1 and Foc4 were the most abundant in soil at the ground radius (r) of 5 cm from Brazilian plant and the depth of 25 to 30 cm under the ground at 30 days after inoculation. When the r values were 15 and 30 cm, the contents of Foc in soil at the depth of 10~15 cm were higher than those of 0~5 cm and 25~30 cm. In Brazilian rhizosphere soil at the same r value and soil depth, the contents of Foc4 were higher than those of Foc1 in most cases.

Conclusion Foc1 and Foc4 have a significantly different spatial and temporal distribution in Brazilian plant and rhizosphere soil, and the content of Foc4 is higher than that of Foc1 in the same space, which provides a theoretical guidance for the epidemic, prediction and prevention and control of banana fusarium wilt.