Research Information System
APPLIED FRUIT SCIENCE, vol.67, no.5, 2025 (SCI-Expanded, Scopus)
Apple rootstocks Malling 9 (M9) and Malling Merton 106 (MM106) are considered most important owing to their high and medium dwarfing attributes. Root rot has emerged as one of the most devastating diseases of apple under both nursery and orchard conditions. However, M9 rootstock, unlike MM106, has shown some degree of tolerance towards root rot pathogens, despite the fact that there is no known source of resistance genes/quantitative trait loci. Various bacterial genera such as Bacillus spp., Gliocadium spp. and Pseudomonas fluorescens have been reported to have biocontrol activities. The aim of the study was to understand the composition of the potential bacteriome associated with the tolerant M9 rootstock in comparison to the susceptible MM106 rootstock against root rot diseases using a metagenomics approach. The composite samples of rootstocks M9 and MM106 were sequenced separately using amplicon-based sequencing on the Illumina platform. Nearly 25-29 and 25-28 million reads were obtained and a total of 941 and 559 bacteria were identified from M9 and MM106 rootstocks, respectively. The relative abundance of bacterial genera such as Rhodanobacter, Burkholderia, Clostridium and Legionella were found in both rootstocks, with higher abundance in M9 rootstock. However, some bacterial genera, having known bioagent potential viz., Paraburkholderia, Paenibacillus, Rhodhanobacter, and Bacillus, were only identified in the M9 rhizosphere, which might be providing tolerance to the M9 rootstock against root rot disease. Our findings demonstrate the utility of metagenomic next-generation sequencing (m-NGS) as a valuable tool for identifying potential bacteriome associated with M9 rootstock's tolerance to root rot disease in apples. This study provides valuable insights into isolating potential bacteria from the rhizosphere of M9 rootstock for the development of bioformulations aimed at suppressing root rot pathogens in apple cultivation. Furthermore, it enhances our understanding of the utilization of M9 rootstock in apple cultivation. Bioformulations should be developed in future for disease management. Further functional metagenomics and transcriptomics could elucidate microbial mechanisms of disease suppression. This information can also be helpful for future breeding programmes.