Identifying the associated gene more precisely in the second-round analysis. The knockdown effects of the marker genes involved in the salicylic acid (SA)-related plant defense response pathway in plants that were transfected with hairpin RNA and that are specific to PhaTF15 and PhaTF21. The RNA levels of PhaPR1, PhaNPR1, PhaTF15 and PhaTF60 were analyzed in healthy (H) plants, plants that were infiltrated with Agrobacterium that carried an empty pB7GWIW2 vector (agro-v), or Agrobacterium that carried pB7GWIW2 to deliver different hairpin RNAs that were specific to PhaTF15 (PhaTF15 hpRNA), PhaTF21 (PhaTF21 hpRNA), PhaRNA (PhaRNA), or PhaTF60 (PhaTF60 hpRNA). The Agrobacterium strain that carried the partial PhaTF15 cDNA was used as a positive control (P), and PhaTF60 was used as a negative control. The plants that were pretreated with salicylic acid (SA) to induce the SA-related plant defense response are indicated. Phalaenopsis Ubiquitin 10 was used as an internal control.