WRKY71转录因子调控木质素生物合成基因促进根中质外体屏障形成并增强植物排盐能力

Abstract

The Casparian strip (CS) and suberin form the apoplastic barrier, which blocks solute entry into the vascular stele under high-salt conditions. Here, transcriptome analysis of Arabidopsis roots during three stages of apoplastic barrier development (undifferentiated, differentiating, and mature) revealed differential expression of the transcription factor gene WRKY71 . We generated WRKY71 -overexpression (OE) and WRKY71- complementation (COM) lines. Metabolomics analysis showed that WRKY71 promotes the biosynthesis of S-type lignin monomers. Compared to wild type and wrky71 plants, WRKY71- OE and COM plants showed enhanced apoplastic barrier formation and less Na + accumulation under 100 mM NaCl treatment, exhibiting better salt-exclusion ability during germination and seedling growth. Yeast one-hybrid assays revealed that WRKY71 interacts with the lignin biosynthesis genes 4CL3 and CUTICLE DESTRUCTING FACTOR 1 ( CDEF1 ). WRKY71 promotes 4CL3 expression and inhibits CDEF1 expression, as determined by dual-luciferase reporter assay. To further investigate the functions of 4CL3 and CDEF1 , we generated the corresponding OE lines. Under 100 mM NaCl treatment, 4CL3 -OE plants showed enhanced salt tolerance through increased CS formation, whereas CDEF1 -OE plants showed increased salt sensitivity due to inhibited suberin formation. Our identification of the WRKY71– 4CL3 / CDEF1 module sheds light on the role of the apoplastic barrier in salt tolerance.