WRKY Transcription Factors in Nicotiana tabacum Modulate Plant Immunity against Whitefly via Interacting with MAPK Cascade Pathways

WRKY transcription factors are key regulators of many plant processes, most notably coping with biotic and abiotic stresses. Recently, the function of WRKY in plant defense against phloem-feeding insects such as whitefly ( ) has been brought to attention. In this study, we found that the expression levels of , and were significantly upregulated when tobacco plants were infested with whiteflies or treated with salicylic acid. Compared to controls, whiteflies lived longer and laid more eggs on -silenced tobacco plants but performed less well on -overexpressing plants. The three NtWRKYs interacted with five mitogen-activated protein kinases (NtMAPKs) in vivo and in vitro. These results suggest that the WRKYs in tobacco positively modulate plant defense against whiteflies through interaction with the mitogen-activated protein kinase cascade (MAPK cascade) pathways, and thus provide new insights into plant defense against phloem-feeding insects.