Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Stahlhut, Katherine [1], Dowell, Jordan [2], Temme, Andries [3], Burke, John [4], Goolsby, Eric [5], Mason, Chase [6].

Genetic control of arbuscular mycorrhizal colonization in Helianthus annuus.

Plant symbiosis with arbuscular mycorrhizal (AM) fungi provides many benefits for plants, including increased nutrient uptake, drought tolerance, and belowground pathogen resistance. In order to have a better understanding of the genetic architecture of mycorrhizal symbiosis, we conducted a genome-wide association study (GWAS) by phenotyping a diversity panel of cultivated sunflower (Helianthus annuus) for root colonization under inoculation with the AM fungus Rhizophagus intraradices. This mapping panel consists of 261 inbred lines that capture approximately 90% of the genetic diversity present in the cultivated sunflower germplasm. Using a mixed linear model approach with a high-density genetic map, we determined regions of the genome that are likely associated with AM colonization in sunflower. Additionally, we used a ‘core 12’ set of twelve diverse lines (representing approximately 50% of the genetic diversity in the cultivated germplasm) to assess the effect that inoculation with AM fungi has on shoot biomass and macronutrient uptake. Colonization rate amongst lines in the mapping panel ranged from 0 to 70% and was not correlated with mycorrhizal growth response, shoot P response, or shoot K response among the core 12 lines. Association mapping yielded three SNPs that were significantly associated with AM colonization rate. These SNPs explained 19.0%, 14.4%, and 27.9% of the variance in three different metrics used to measure the degree of root colonization. Three genes of interest identified from the significant regions that contained these SNPs are likely related to plant defense. Overall, our data suggests that candidate genes involved in plant defense affect AM colonization rates within cultivated sunflower, and that these genes have a large effect size.

1 - University of Central Florida, 4110 Libra Dr., Orlando, FL, 32816, United States
2 - University of Central Florida, Department of Biology, 4110 Libra Dr., Orlando, FL, 32816, United States
3 - University Of Georgia Athens, Department Of Plant Biology, 2502 Miller Plant Sciences, The University Of Georgia, Athens, GA, 30602, United States
4 - University Of Georgia Athens, Department Of Plant Biology, 2502 Miller Plant Sciences, The University Of Georgia, Athens, Athens, GA, 30602, USA
5 - University Of Central Florida, 4000 Central Florida Blvd, BLDG20, BL301, Orlando, FL, 32816, United States
6 - University Of Central Florida, Department Of Biology, 4110 Libra Dr, Orlando, FL, 32816, United States

Keywords:
mycorrhizal growth response
AM fungi
AMF
mycorrhizal symbiosis
GWAS
genome-wide association study
sunflower
Helianthus annuus
Rhizophagus intraradices.

Presentation Type: Oral Paper
Session: SYMB2, Symbioses: Plant, Animal, and Microbe Interactions II
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 10:15 AM
Number: SYMB2002
Abstract ID:137
Candidate for Awards:None