Characterization of yellow-green leaf1 mutant for improved phosphorus use efficiency and rapid offspring screening in Tartary buckwheat

Leaf color mutations provide valuable genetic resources for elucidating the molecular regulatory mechanisms of plant growth and serve as efficient tools for screening offspring in crossbreeding. In this study, a Tartary buckwheat (Fagopyrum tataricum) mutant with yellow-green leaves (yl1) was isolated from Co-60-gamma-radiation mutation bank. Compared to wild type (WT), yl1 showed similar biomass and yield, despite a lower chlorophyll content and net photosynthetic rate. However, yl1 displayed significantly higher total phosphorus content after 14 days of medium and low phosphorus treatment. By using yl1 as the maternal parent, hybrid offspring could be visually distinguished at the cotyledon stage. Genetic analysis revealed that the yl1 phenotype was attributed to a single recessive mutation. Combined metabolome and transcriptome analysis identified 205 differential expressed metabolites (DEMs) and 123 differential expressed genes enriched in 30 pathways or metabolisms between yl1 and WT. Remarkably, the upregulation of SPX3, 5PTase2, PHO1, PAP3, PAP2, PAP7, and IPAP16, which are involved in enhancing phosphorus absorption, assimilation, transport, and remobilization, along with PLD zeta 1, GDPD1, MGD2, and NPC4L, which contribute to improving lipid metabolism, collectively resulted in high accumulation of 41 phosphorus-containing DEMs (including 37 lipids) in yl1. This study emphasizes the potential of yl1 for effective screening of offspring and uncovers the interplay between photosynthesis and lipid metabolism, providing valuable insights to improve phosphorus use efficiency in Tartary buckwheat.