Genome‑wide association studies dissect low‑phosphorus stress response genes underling feld and seedling traits in maize

Phosphorus (P) is an essential element for plant growth, and its defciency can cause decreased crop yield. This study systematically evaluated the low-phosphate (Pi) response traits in a large population at maturity and seedling stages, and explored candidate genes and their interrelationships with specifc traits. The results revealed a greater sensitivity of seedling maize to low-Pi stress compared to that at maturity stage. The phenotypic response patterns to low-Pi stress at diferent stages were independent. Chlorophyll content was found to be a potential indicator for screening low-Pi-tolerant materials in the feld. A total of 2900 and 1446 signifcantly associated genes at the maturity and seedling stages were identifed, respectively. Among these genes, 972 were uniquely associated with maturity traits, while 330 were specifcally detected at the seedling stage under low-Pi stress. Moreover, 768 and 733 genes were specifcally associated with index values (low-Pi trait/normal-Pi trait) at maturity and seedling stage, respectively. Genetic network diagrams showed that the low-Pi response gene Zm00001d022226 was specifcally associated with multiple primary P-related traits under low-Pi conditions. A total of 963 out of 2966 genes specifcally associated with traits under low-Pi conditions or index values were found to be induced by low-Pi stress. Notably,ZmSPX4.1andZmSPX2were sharply up-regulated in response to low-Pi stress across diferent lines or tissues. These fndings advance our understanding of maize’s response to low-Pi stress at diferent developmental stages, shedding light on the genes and pathways implicated in this response.