Molecular study of Serratia marcescens, a bacterium associated with roots of maize (Zea mays L.), using 16S rDNA in Limpopo Province, South Africa

Maize the most important grain crop in South Africa produced under diverse environments is prone to dangerous pathogenic bacteria which needs better control and management. One of the bacteria that can affect maize yield is Serratia a gram-negative, facultatively anaerobic, motile bacterium. Colonies on (aerobic) nutrient agar plates are circular and have a dark red to pink colour. This study isolated and identified Serratia bacterium from maize fields in Limpopo, South Africa. The molecular study was done in 2022 at the Aquaculture Research Unit, University of Limpopo. To identify the bacterium associated with maize, for extraction DNA Chelex method was used then 16S rDNA marker was used. The bacterium was identified as S. marcescens. The Nblast analysis showed South African S. marcescens had 97% similarity with a population from Brazil (MH127785), and South Korea (MN082049). Phylogenetic analysis using maximum likelihood placed this species with those molecularly identified as S. marcescens in the same clade with highly supported (100) bootstrap values. In conclusion, this species is identified using 16S rDNA properly. However, using other DNA markers to understand S. marcescens phylogeny better is recommended.