Integrated Genetic Diversity and Multi-Omics Analysis of Colour Formation in Safflower

Area of Science:

• Plant genetics and breeding
• Agricultural science
• Biochemistry

Background:

• Safflower (Carthamus tinctorius L.) is a vital crop, yet its genetic diversity and flower color variations are poorly understood.
• Understanding these aspects is crucial for effective germplasm conservation and crop improvement.

Purpose of the Study:

• To evaluate the genetic diversity of safflower germplasm resources.
• To elucidate the molecular mechanisms underlying safflower flower color variation.

Main Methods:

• Agronomic trait evaluation and Indel marker analysis of 614 safflower germplasm resources.
• Population structure, phylogenetic, and principal coordinate analyses.
• Transcriptome, metabolome, and pigment content analyses.

Main Results:

• High variability observed in agronomic traits; Indel markers revealed moderate genetic diversity (I=0.551, PIC=0.296).
• Safflower genotypes were classified into four subgroups, and a core germplasm of 214 accessions was established.
• Differential expression of flavonoid synthesis genes (CHS, F3H, ANS, BZ1) and distinct metabolic pathway enrichment (phenylpropanoid pathway) were identified in different colored safflowers.
• Red safflowers showed the highest levels of anthocyanins and carotenoids.

Conclusions:

• The established core germplasm effectively represents the original safflower genetic resources.
• Flower color variation in safflower is attributed to differential gene expression and metabolite accumulation along the phenylpropanoid pathway.
• Findings provide insights for safflower germplasm management and breeding for desired flower colors.