Skip to main content
ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sugarbeet and Potato Research » Research » Publications at this Location » Publication #375164

Research Project: Increasing Sugar Beet Productivity and Sustainability through Genetic and Physiological Approaches

Location: Sugarbeet and Potato Research

Title: Bacterial endophytes as indicators of susceptibility to Cercospora Leaf Spot (CLS) disease in Beta vulgaris L

item BROCCANELLO, CHIARA - Universita Di Padova
item Bolton, Melvin
item SECOR, GARY - North Dakota State University
item Richards, Christopher
item RAVI, SAMATHMIKA - Universita Di Padova
item CONCHERI, GIUSEPPE - Universita Di Padova
item CAMPAGNA, GIOVANNI - Cooperative Beet Producers
item SQUARTINI, ANDREA - Universita Di Padova
item STEVANATO, PIERGIORGIO - Universita Di Padova

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2022
Publication Date: 6/23/2022
Citation: Broccanello, C., Bolton, M.D., Secor, G., Richards, C.M., Ravi, S., Concheri, G., Campagna, G., Squartini, A., Stevanato, P. 2022. Bacterial endophytes as indicators of susceptibility to Cercospora Leaf Spot (CLS) disease in Beta vulgaris L. Scientific Reports. 12. Article e10719.

Interpretive Summary: Cercospora leaf spot is a disease of sugar beet that is found in nearly all areas where this crop is grown. Despite the global importance of this disease, varieties with durable genetic resistance do not exist. Several reports have recently suggested that bacterial endophytes may play a role in resistance to important crop pests and pathogens. Endophytes are organisms that live inside a plant, but do not cause disease. In this study, we used next generation sequencing technologies to identify bacterial endophytes living in the wild relative of sugar beet called sea beet. Five genera of bacteria were found to be less abundant in healthy sea beet plants compared to diseased plants with Cercospora leaf spot. These data suggest that endophyte abundance is associated with susceptibility to Cercospora leaf spot. Therefore, monitoring these species may be a useful way to screen sugar beet germplasm for resistance to this important disease.

Technical Abstract: The fungus Cercospora beticola causes Cercospora Leaf Spot (CLS) of sugar beet (Beta vulgaris L.). Despite the global importance of this disease, a durable resistance to CLS has not been obtained and thus the breeding of tolerant hybrids is still a major challenge. Knowledge of the leaf microbiome composition can offer useful predictors to assist breeders but is yet an untapped resource in sugar beet breeding efforts. Using Ion GeneStudio S5 technology to sequence amplicons from seven 16S rRNA hypervariable regions, we identified the most recurring endophytes within leaves of infected and healthy sea beets (B. vulgaris ssp. maritima). This allowed the design of taxon-specific primer pairs to quantify the abundance of each of the most representative endophytic species in 302 wild accessions of sea beet that were either healthy (n=157) or infected with CLS (n=145) by qPCR. The screened bacterial genera included Methylobacterium, Aurantimonas, Mucilaginibacter, Propionibacterium, Sphingomonas, Pseudomonas and Massilia. Five out of seven genera were found to be significantly less abundant in healthy plants. These data suggest that endophyte abundance is a trait that can be correlated to an increased sensitivity to CLS disease. This evidence can prompt novel protocols to assist plant breeding of sugar beet in the pursuit of improved pathogen-resistance.