Key Genes Regulating the Adaptive Evolution of Floral Size
Among the 157 genes affected by environmental selection, 21 genes were DEGs. Most of these genes were located on chromosomes 3, 5 and 7, among which the greatest number of candidate genes was distributed on chromosome 7 (Figure 6A and Figure S8). The results of QTL mapping also revealed the existence of genes related to controlling organ morphology on chromosome 7 of Aquilegia (Edwards et al., 2021). Six genes whose variations were affected by environmental selection showed nonsynonymous mutations: Aqcoe1G340100 (Ankyrin repeat family protein), Aqcoe1G488100 (ascorbate peroxidase 1),Aqcoe3G242600 (glutamate dehydrogenase 2), Aqcoe5G182600(cytokinin oxidase 5), Aqcoe5G459400 (OBP3-responsive gene 1), and Aqcoe7G135600 (pleiotropic drug resistance 11) (Figure 6A). Except for Aqcoe1G488100 , which was related to Bio8, the remaining genes were related to Bio2. These six genes were essential for plant growth and development. Additionally, Aqcoe5G459400 andAqcoe7G135600 were located in the orange module and saddle brown module related to spur length, respectively. The expression ofAqcoe5G459400 was significantly negatively correlated with spur length (p = 0.007) (Figure 6C), while that of Aqcoe7G35600showed no significant correlation with spur length (p = 0.3481). The selected SNP in Aqcoe5G459400 showed two mutations: the NE group was mostly C, the EL group was mostly A, and the number of A and C in the CN and NW groups was not much different (Figure 6B). Therefore,Aqcoe5G459400 may be a candidate gene for A. viridifloraspur length to adapt to environmental evolution. WGCNA showed that the genes that interacting with Aqcoe5G459400 wereAqcoe2G056600 , Aqcoe2G172400 , Aqcoe3G439700 ,Aqcoe7G244300 and Aqcoe7G395200 . Additionally, a binding site exists for the ABI3/VP1 transcription factor located 1.8 kb upstream of the Aqcoe5G459400 gene.