Transcriptome profiles of Arabidopsis plant harboring inducible VND7 system with flg22 treatment

Under environmental challenges such as pathogen attack, a growth-defense trade-off limits xylem vessel development. For understanding the mechanism regulating this trade-off, we investigated the effect of pathogen responses induced by the peptide defense elicitor flagellin22 (flg22) on VASCULAR-RELATED NAC-DOMAIN7 (VND7)-dependent xylem vessel formation in Arabidopsis. Treatment with flg22 decreased xylem transport and delayed ectopic xylem vessel (SCW) differentiation in plants with a dexamethasone-inducible VND7 system, suggesting that the plant prioritized defense responses over xylem formation. Consistent with this, transcriptome analysis revealed that flg22 treatment suppressed SCW-related genes and activated immune-related genes. Salicylic acid (SA) treatment had a similar inhibitory effect on VND7-dependent xylem vessel formation; this highlights the role of SA, as a key mediator of the competition between xylem vessel formation and immune responses.