Evolution of the gene family in plants and its role in the response mechanism to phosphorus stress.

Molecular and genomic studies have shown the presence of a large number of gene family members in plants, some of which have been proved to act in P signalling and homeostasis. In this study, the molecular and evolutionary characteristics of the gene family in plants were comprehensively analysed, and the mechanisms underlying the function of genes in P signalling and homeostasis in the model plant species () and rice (), and in important crops, including wheat (), soya beans () and rapeseed (), were described. Emerging findings on the involvement of genes in other important processes (i.e. disease resistance, iron deficiency response, low oxygen response and phytochrome-mediated light signalling) were also highlighted. The available data suggest that genes are important regulators in the P signalling network, and may be valuable targets for enhancing crop tolerance to low P stress. Further studies on SPX proteins should include more diverse members, which may reveal SPX proteins as important regulatory hubs for multiple processes including P signalling and homeostasis in plants.