Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Bellis, Emily [1].

Genomics of sorghum local adaptation to a parasitic plant.

Host-parasite coevolution can maintain high levels of diversity in traits involved in species interactions.  To identify host polymorphism associated with the distribution of parasites, we developed species distribution models for the parasitic weed Striga hermonthica and used genomic data from over 2,000 global landraces to identify regions of the Sorghum bicolor genome strongly associated with S. hermonthica distribution. We find diverse loss-of-function alleles in the known sorghum resistance locus LGS1 exhibit statistical associations with predicted distribution of S. hermonthica and are geographically widespread among sorghum landraces, supporting a role in local adaptation to parasitic plant occurrence.  However, low frequency of these alleles outside of S. hermonthica endemic areas suggests tradeoffs could limit their distribution. In support of tradeoffs related to endogenous function of strigolactones in hosts, we show elevated expression of strigolactone biosynthesis pathway genes in root transcriptomes of resistant vs. susceptible sorghum varieties under nutrient stress.  Genome-wide analyses reveal additional loci with evidence for locally adaptive natural variation including genes involved in cell wall modification, lignin deposition, and strigolactone perception. An excess of high-frequency polymorphism surrounding candidate loci supports an important role of balancing selection in the long-term maintenance of diversity in alleles contributing to resistance in the sorghum-Striga hermonthica pathosystem. 

1 - The Pennsylvania State University

geographic species distribution
Parasitic Plants
genotype-environment association analysis.

Presentation Type: Poster This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PSM002
Abstract ID:291
Candidate for Awards:None

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