Diversity of pathogens associated to cassava root rotting in Cameroon

Cassava is the second most important food crop in Cameroon, after rice, and a staple food cultivated in eight out of the ten regions of the country. The presence of rotting in the tuberous root noticed at the time of harvesting is one of the emerging production constraints. This work aims to (i) describe and map the different types of cassava rotting in major production zones in humid forest of Cameroon, and (ii) identify the underlying causal agent(s) by using metagenomics analysis. Field survey showed that root rotting was present in all the three locations with field incidence varying from 14.1 to 84.1 %. The dry rot has 100 % prevalence and a higher incidence (58-100 %) in 8 fields out of 9 while wet rotting has 77.8% prevalence with lower incidence (< 42 %) except in one field where the incidence was 80%. In general, the average severity of dry rot was lower (2-3.33) than the average severity of wet rot (3.5-5) in the all the fields. Further activities to conclude this work include, (1) analysis of available NGS sequencing data to reveal fungal microbial community present in rotting, (2) DNA extraction and PCR analysis with bacterial primer pairs V5V7 on backup samples; (3) NGS sequencing with bacterial primer pairs V5V7 to reveal the bacteria community associated to cassava rotting. This will pave the way towards understanding the disease causal agent for better management options.