CONCLUSION
In conclusion, we demonstrated that the WRK33 transcription factor can act as a core regulator of AR156-induced ISR resistance against different lifestyles pathogens (Figure 7). In Arabidopsis , AR156 colonizes in Arabidopsis roots, inducing ISR signaling, and the signals are transferred to the leaves. WRKY33 , a positive regulator of AR156-induced systemic resistance, was upregulated by AR156 induced. AR156 regulated the expression of CYP71A13 andPAD3 through WRKY33 thereby increasing the intracellular accumulation of camalexin upon infection with different pathogens. On the other hand, AR156 relied on PEN3 and PDR12 to transfer camalexin accumulated outside the cell to protect against different pathogens. Our study firstly raises that WRKY33 is involved in regulating the accumulation and secretion of phytoalexin induced by AR156 as a core factor. In addition, our study systematically elucidates the mechanism of PGPR-triggered ISR resistance to broad-spectrum pathogens and offers a theoretical basis for developing and applying new biopesticides.