Plant symbiosis with arbuscular mycorrhizal (AM) fungi provides many benefits, including increased nutrient uptake, drought tolerance, and belowground pathogen resistance. To develop a better understanding of the genetic architecture of mycorrhizal symbiosis, we conducted a genome-wide association study (GWAS) of this plant-fungal interaction in cultivated sunflower. A diversity panel of cultivated sunflower (Helianthus annuus L.) was phenotyped for root colonization under inoculation with the AM fungus Rhizophagus intraradices. Using a mixed linear model approach with a high-density genetic map, we identified genomic regions that are likely associated with R. intraradices colonization in sunflower. Additionally, we used a set of twelve diverse lines to assess the effect that inoculation with R. intraradices has on dried shoot biomass and macronutrient uptake. Colonization among lines in the mapping panel ranged from 0–70% and was not correlated with mycorrhizal growth response, shoot phosphorus response, or shoot potassium response among the Core 12 lines. Association mapping yielded three single-nucleotide polymorphisms (SNPs) that were significantly associated with R. intraradices colonization. This is the first study to use GWAS to identify genomic regions associated with AM colonization in an Asterid eudicot species. Three genes of interest identified from the regions containing these SNPs are likely related to plant defense.

植物与丛枝菌根 (AM) 真菌共生提供了许多好处，包括增加养分吸收、耐旱和地下病原体抗性。为了更好地了解菌根共生的遗传结构，我们对栽培向日葵中的这种植物-真菌相互作用进行了全基因组关联研究 (GWAS)。对栽培向日葵 ( Helianthus annuus L.)的多样性小组在接种 AM 真菌Rhizophagus intraradices 的情况下对根部定植进行了表型分析。使用具有高密度遗传图谱的混合线性模型方法，我们确定了可能与R. intraradices相关的基因组区域在向日葵中定植。此外，我们使用一组 12 个不同的品系来评估接种R.intraradices对干枝生物量和大量营养素吸收的影响。绘图面板中品系之间的定植范围为 0-70%，并且与核心 12 品系中的菌根生长反应、枝条磷反应或枝条钾反应无关。关联映射产生了三个单核苷酸多态性 (SNP)，它们与R.intraradices定植显着相关。这是第一项使用 GWAS 来识别与 Asterid eudicot 物种中 AM 定植相关的基因组区域的研究。从包含这些 SNP 的区域中鉴定出的三个感兴趣的基因可能与植物防御有关。