Relatively Low Light Intensity Promotes Phosphorus Absorption and Enhances the Ethylene Signaling Component EIN3 in Maize, Wheat, and Oilseed Rape

Abstract

Previous studies have found that once seedlings break the soil, light can induce the degradation of the key ethylene signaling element ethylene insensitive 3 (EIN3), so as to indirectly inhibit the synthesis of ethylene. Ethylene is the most important hormone in phosphorus absorption by plants, which induces the expression of acid phosphatase (APase) and phosphorus starvation response genes. Therefore, it might be speculated that changes in light intensity could regulate phosphorus absorption to some degree. However, there are few reports on the mechanism by which light intensity regulates phosphorus metabolism. In this study, the effects of different light intensities on phosphorus assimilation and metabolism in plants were studied. The results showed that relatively low light intensity could promote the secretion of APase, so as to increase the concentration of plant total phosphorus and cellular Pi. However, the low light intensity may also inhibit plant growth. Among the three species, oilseed rape was the most sensitive to the low light intensity. The steady-state level of the EIN3 protein decreased significantly under a relatively high light intensity; while the ethylene level also decreased under the high light intensity. Therefore, appropriate reductions in light intensity may simultaneously promote phosphorus assimilation and maintain plant growth.