A Novel Phospholipase A₁ Gene from Tritipyrum Improves Wheat Early Ripening and Salt Tolerance

It is important to breed salt-tolerant and early ripening wheat cultivars. Using preliminary transcriptomic data, a phospholipase A₁ gene, TtPLA_1-1, was screened from salt-tolerant Tritipyrum "Y1805". The TtPLA_1-1 expression level in roots was significantly higher than those in stems and leaves under salt stress. TtPLA_1-1 overexpression (OE) wheat lines showed strong salt tolerance levels and early ripening. The PLA, lysophospholipid, free fatty acid, proline, and soluble sugar contents, as well as root vitality and catalase and peroxidase activities, in OE lines were significantly higher than those in the WT plants under normal and salt-stress conditions. However, the malondialdehyde content decreased. Conversely, TtPLA_1-1 downregulation in "Y1805" using a virus-induced gene silencing system decreased the salt tolerance. According to both transcriptome and yeast two-hybrid analyses, the salt stress-, plant growth-, and flowering-related terms "response to water deprivation", "response to abscisic acid", "removal of superoxide radicals", "carbohydrate metabolic process", "intracellular signal transduction", "l-asparagine biosynthetic process", "positive regulation of growth", and "regulation of photoperiodism, flowering" were enriched. An interaction between TtPLA_1-1 and TtRFI2L (RED AND FAR-RED INSENSITIVE 2-like) was revealed. Additionally, TtRFI2L silencing reduced the salt tolerance. In summary, TtPLA_1-1 improved wheat salt tolerance and promoted early maturation, making it a valuable gene for wheat breeding and cultivation.