Leaf bacteriome in sugar beet show differential response against Beet curly top virus (BCTV) during susceptible and resistant interactions

Authors: Majumdar, Raj; Strausbaugh, Carl; Eujayl, Imad

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/20/2022
Publication Date: 11/20/2022
Citation: Majumdar, R., Strausbaugh, C.A., Eujayl, I.A. 2022. Leaf bacteriome in sugar beet show differential response against Beet curly top virus (BCTV) during susceptible and resistant interactions. Phytopathology. 112:S3.65. https://doi.org/10.1094/PHYTO-112-11-s3.1.
DOI: https://doi.org/10.1094/PHYTO-112-11-S3.1

Interpretive Summary: Sugar beet genetic resistance to the Beet curly top virus (BCTV) is limited and needs to be supplemented with neonicotinoid seed treatments to achieve acceptable control. Identification of additional factors associated with host plant resistance will therefore be helpful in designing alternative strategies for future disease control. Role of host plant microbiome is known to play a critical role in host resistance against stresses. How the sugar beet microbiome might contribute to host resistance against BCTV is unknown. In this work we demonstrate a potential role of the sugar beet leaf microbiome in BCTV resistance. The data presented here might help in designing novel mitigation strategies in the future in an ecofriendly manner.

Technical Abstract: Beet curly top virus (BCTV) is an important sugar beet yield limiting disease in semi-arid production areas. Genetic resistance to BCTV is limited, therefore identification of additional resistance factors will aid in developing novel mitigation strategies. Using 16S rRNA sequencing and BCTV resistant (R) sugar beet genotypes (KDH13, KDH4-9) along with a susceptible (S) genotype (KDH19-17), we investigated changes in leaf bacteriome after BCTV infection. In 5 wk-old plants, Cyanobacteria were predominant (~90%), whereas in 10 wk-old plants Firmicutes (11-66%), Bacteroidetes (17-26%), and Verrucomicrobia (12-29%) were predominant and genotype dependent. Both Bacteroidetes and Verrucomicrobia, increased only in R lines post infection and more so at 4 wk post inoculation (pi). Brevibacillus increased at 6 d pi, and Akkermansia and Bacteroides at 4 wk pi in the R lines. Linear discriminant analysis Effect Size identified potential biomarkers that were differentially regulated in the R and S lines after infection. Functional profiling of bacteriome at 6 d pi revealed enrichment of bacteria only in the KDH4-9 resistant line associated with the TCA cycle, polyisoprenoid, and L-methione biosynthesis pathways. Whereas at 4 wk pi, bacteria associated with tryptophan and palmitate biosynthesis in the R lines and uridine monophosphate, phosphatidyl glycerol, and phospholipid biosynthesis in the S line, were enriched. Future characterization of bacterial genera with antiviral properties will be investigated as potential biocontrol agents or biomarkers for BCTV resistance in sugar beet.