Diversity of viruses and viroids in the rhizosphere of common bean cultivars differing in resistance to the fungal root pathogen Fusarium oxysporum

The rhizosphere microbiome plays a key role in plant protection against soil-borne pathogens. Plant breeding for resistance against soil-borne pathogens can alter the rhizosphere microbiome. However, most studies have focused on bacterial and fungal communities, leaving the role of the virus and viroids unassessed. Here, we tested the influence of resistance breeding on the composition of rhizosphere viruses and viroids. By analyzing metatranscriptomes from the rhizosphere of common bean (Phaseolus vulgaris) cultivars with varying resistance to the soil-borne pathogen Fusarium oxysporum, we recovered sequences representing 78 and 23 novel populations of viruses and viroids, respectively. We compared the abundances of these infectious agents across the different cultivars and found that the Fusarium-resistant cultivar harbored >1.2 times more viroids and a more different composition of viroids and viruses than less resistant plants. Given their role in interfering with host metabolism and their potential influence on plant-fungi associations, our study suggests that changes in the rhizosphere infectome are an important consideration in breeding for resistance against soil-borne pathogens.

Automated summary

This study tested the influence of resistance breeding on the composition of rhizosphere viruses and viroids. By analyzing metatranscriptomes from common bean (Phaseolus vulgaris) cultivars with varying resistance to the soil-borne pathogen Fusarium oxysporum, it was found that the resistant cultivar harbored more viroids and a different composition of viroids and viruses than less resistant plants. This study suggests that changes in the rhizosphere infectome are an important consideration in breeding for resistance against soil-borne pathogens.