GbABR1 is associated with Verticillium wilt resistance in cotton

We cloned the GbABR1 gene from highly resistant Gossypium barbadense Xinhai15 based on the candidate genes screened by transcriptome sequencing that were related to resistance to Verticillium wilt. A sequence characteristic analysis showed that GbABR1 was an ERF subfamily B4 member and was a new member of the AP2 family of sea-island cotton. The GbABR1 gene was expressed highly in roots compared with the levels in leaves and stems in cotton. Expression was enhanced significantly in cotton after infection by Verticillium dahliae, indicating that GbABR1 probably plays an important role in the response to biotic stress. The results of subcellular localisation showed that GFP:GbABR1 was localised to the nucleus. GbABR1 silencing via the virus-induced gene silencing (VIGS) method indicated that the incidence of disease and the disease index in VIGS-silenced plants were much higher than in the control after infection by Verticillium dahliae. The GbABR1-overexpressing Arabidopsis plants showed similar resistance to Verticillium dahliae compared to the wild type. These results indicate that the GbABR1 gene plays a positive role in resistance to Verticillium wilt. The GbABR1-overexpressing Arabidopsis plants presented dwarfism, early maturation and early bolting compared with wild-type plants, suggesting that GbABR1 also participates in growth and development.