Pathogen avirulence (Avr) effectors interplay with corresponding plant resistance (R) proteins and activate robust plant immune responses.Although the expression patt of Avr genes has been tied to their functions for a long time,it is still not clear how Avr gene expression patts impact plant-microbe interactions.Here,we selected PsAvr3b,which shows a typical effector gene expression patt from a soybean root pathogen Phytophthora sojae.To modulate gene expression,we engineered PsAvr3b promoter sequences by in situ substitution with promoter sequences from Actin (constitutive expression),PsXEG1(early expression),and PsNLP1 (later expression) using the CRISPR/Cas9.PsAvr3b driven by different promoters resulted in distinct expression levels across all the tested infection time points.Importantly,those mutants with low PsAvr3b expression successfully colonized soybean plants carrying the cognate R gene Rps3b.To dissect the difference in plant responses to the PsAvr3b expression level,we conducted RNA-sequencing of different infection samples at 24h postinfection and found soybean immune genes,including a few previously unknown genes that are associated with resistance.Our study highlights that fine-tuning in Avr gene expression impacts the compatibility of plant disease and provides clues to improve crop resistance in disease control management.