Salicylic acid influences the resistance of colored calla lily to soft rot (Pectobacterium carotovorum) via the TGA2-LNC88940-miR528-SOD module.

Soft rot is a major disease affecting the production of colored calla lily, significantly compromising its ornamental, commercial, and market value. In this study, we identified potential long non-coding RNAs (lncRNAs) in colored calla lily (Zantedeschia elliottiana) leaves infected with soft rot via transcriptome sequencing. Among them, long non-coding RNA 88490 (LNC88940) was identified as a differentially expressed lncRNA that was significantly upregulated following soft rot infection. The results revealed that LNC88940 functions as an endogenous target mimic (eTM) for miR528, reducing the expression level of miR528 and thereby indirectly promoting superoxide dismutase (SOD) expression. Experiments involving transient overexpression and silencing of LNC88940 and SOD revealed that overexpression significantly reduced lesion areas and enhanced resistance to soft rot, whereas silencing had the opposite effect. Additionally, the increase in salicylic acid (SA) levels in leaves following soft rot infection was closely associated with the upregulation of LNC88940 expression. Further investigation revealed that TGACG-binding factor 2 (TGA2) can directly bind to the promoter of LNC88940, thereby increasing its expression. This study reveals the crucial role of the SA-mediated TGA2-LNC88940-miR528-SOD module in regulating the resistance of colored calla lily to soft rot, providing new theoretical insights into the lncRNA-mediated regulation of disease resistance in ornamental horticultural crop species.