Research advances in molecular mechanism of mineral nutrition-mediated regulation of plant flowering time

Flowering is a necessary process for higher plants to produce seeds and reproduction, and it is regulated by factors such as photoperiod, temperature, age, hormones, and nutrients. Exploring the mechanisms and regulatory pathways of nutrients in plant flowering, and identifying the key genes can help improve crop nutrient utilization efficiency, regulate flowering time, and increase yield through genetic engineering or molecular breeding. Significant progress has been achieved on the molecular regulating mechanisms of nitrogen, phosphorus, potassium, sulfur, iron, zinc, and copper in recent years. Both low or high nitrogen supply delay the flowering time of plants. Various nitrogen forms such as nitrate, ammonium, and glutamine regulate flowering time through different paths. The nitrate-mediated flowering regulation involves multi-level regulation such as transcription level, post-transcription level, and protein phosphorylation modification, and is associated with flowering pathways such as photoperiod, gibberellin, and age. Ammonium nitrogen and glutamine can regulate rice flowering time by promoting the expression of transcription factor Nhd1, thereby activating the expression of downstream flowering gene Hd3a. Low phosphorus delays plant flowering, while high phosphorus promotes flowering. PHO1-mediated phosphate transport from roots to shoots plays a crucial role in plant flowering transition. The jasmonic acid signal is involved in the inhibition of flowering by phosphorus deficiency. The regulation of flowering by phosphorus nutrition may also be related to flowering pathways such as photoperiod, temperature, and age pathways. Potassium nutrition regulates flowering by affecting the movement of sucrose and FT. Iron deficiency delays flowering through the negative regulation of CO by bHLH38/100/101 transcription factors. The postponed flowering time under Cu deficiency may be related to decreased expression of miR172 and FT. High zinc supply conditions promotes plant flowering while low zinc supply delay plant flowering. In general, nutrient signals have inseparable relationship with plant growth and flowering signaling substances, such as auxin, gibberellins, jasmonic acid, brassinosteroids, strigolactones, nitric oxide, sucrose. The roles of these signaling substances in mineral nutrient-mediated flowering regulation deserve further exploration. In addition, soils often suffered from multiple nutrient stresses, and the nutrients interact with each other. However, it is still unclear how nutrient interactions affect flowering. Soil nutrient stress often occurs in conjunction with other environmental stresses. The molecular mechanisms of the effect of combined nutrient and environmental stress on plant flowering should be investigated as well.