Abstract
Development of
pathogen-resistant crops, such as fungus-resistant cotton, has
significantly reduced chemical application and improved crop yield and quality.
However, the mechanism of resistance to cotton pathogens
such as Verticillium dahliae is still poorly understood. In this
study, we characterized a cotton gene (HDTF1) that was isolated
following transcriptome profiling during the resistance response of cotton to
V. dahliae.HDTF1 putatively encodes a homeodomain transcription
factor, and its expression was found to be down-regulated in cotton upon
inoculation with V.dahliae and Botrytis cinerea. To characterise
the involvement of HDTF1 in the response to these pathogens, we used
virus-induced gene silencing (VIGS) to generate HDTF1-silenced cotton.
VIGS reduction in HDTF1 expression significantly enhanced cotton plant resistance to
both pathogens.HDTF1 silencing resulted in activation of jasmonic acid
(JA)-mediated signaling and JA accumulation. However, the silenced plants were
not altered in the accumulation of salicylic acid (SA) or the expression of
marker genes associated with SA signaling. These results suggest that HDTF1 is
a negative regulator of the JA pathway, and resistance to V. dahliae and
B. cinerea can be engineered by activation of JA signaling.