Ionomic and Metabolomic Analyses Reveal Different Response Mechanisms to Saline-Alkali Stress Between Suaeda salsa Community and Puccinellia tenuiflora Community

Soil salinization imposes severe stress to plants, inhibits plant growth, and severely limits agricultural productivity and land utilization. The response of a single plant to saline-alkali stress has been well investigated. However, the plant community that usually works as a group to defend against saline-alkali stress was neglected. To determine the functions of plant community, in our current work, ( ) community and ( ) community, two communities that are widely distributed in Hulun Buir Grassland in Northeastern China, were selected as research objects. Ionomic and metabolomic were applied to compare the differences between community and community from the aspects of ion transport and phenolic compound accumulation, respectively. Ionomic studies demonstrated that many macroelements, including potassium (K) and calcium (Ca), were highly accumulated in community whereas microelement manganese (Mn) was highly accumulated in community. In community, transportation of K to aboveground parts of plants helps to maintain high K and low Na concentrations whereas the accumulation of Ca triggers the salt overly sensitive (SOS)-Na system to efflux Na . In community, enrichment of Mn in roots elevates the level of Mn-superoxide dismutase (SOD) and increases the resistance to saline-alkali stress. Metabolomic studies revealed the high levels of C6C1-compounds and C6C3C6-compounds in community and also the high levels of C6C3-compounds in community. C6C1-compounds function as signaling molecules to defend against stress and may stimulate the accumulation of C6C3C6-compounds. C6C3-compounds contribute to the elimination of free radicals and the maintenance of cell morphology. Collectively, our findings determine the abundance of phenolic compounds and various elements in community and community in Hulun Buir Grassland and we explored different responses of community and community to cope with saline-alkali stress. Understanding of plant response strategies from the perspective of community teamwork may provide a feasible and novel way to transform salinization land.