Enhanced resistance to Verticillium dahliae in transgenic cotton expressing an endochitinase gene from Phaseolus vulgaris

The cotton wilt disease caused by the fungus Verticillium dahliae reduces total yield and quality in cotton worldwide. Since traditional breeding has achieved only low levels of wilt resistance, we used a transgenic approach to produce wilt tolerant cotton. We produced fertile transgenic T₂ cotton lines by Agrobacterium-mediated transfer of an endochitinase gene from Phaseolus. Transgene integration and expression were confirmed by PCR amplification, Southern blot and Western blot analyses. Seedlings of homozygous T₂ plants with high levels of chitinase expression were evaluated for their tolerance to Verticillium dahliae by infecting them with a spore suspension in a greenhouse. The transgenic plants demonstrated higher degrees of tolerance to the fungus than non-transgenic plants, as measured by foliar disease symptoms, vascular discoloration and plant height. Transgenic plants were also taller than the control ones and are currently being grown in the greenhouse and will be crossed with Iranian cotton breeding lines in a future study.