CanTF, a Novel Transcription Factor in Pepper, Is Involved in Resistance to Phytophthora capsici as well as Abiotic Stresses

Abstract

Stress is usually considered an important factor resulting in plant injury. In this study, we identified a novel transcription factor gene, CanTF (Capsicum annuum transcription factor IIB), and characterized its role in the response to biotic and abiotic stresses. The full-length CanTF cDNA consists of 1488 bp, with a 1281-nucleotide open reading frame (ORF), and encodes a protein containing 426 amino acids with a theoretical molecular weight of 46.84 kDa. Real-time quantitative PCR revealed that CanTF is a stress-induced gene, with increased expression levels under both biotic and abiotic stresses. The expression of CanTF in pepper organs, especially roots, was highly induced by inoculation with an avirulent strain of Phytophthora capsici. Additionally, the differential expression of CanTF was observed under abiotic stresses, i.e., earlier expression was detected after cold, drought, and SA treatments than after salt and H2O2 treatment, suggesting its role in responses to various abiotic stresses. Furthermore, the silencing of CanTF by virus-induced gene silencing reduced the expression of defense-related genes (CaPR1, CaDEF1, and CaSAR82) under P. capsici inoculation. POD and root activity levels were lower after gene silencing than in controls, demonstrating the positive regulatory effect of CanTF against P. capsici. These results suggested that CanTF is a stress-induced gene involved in strengthening the pepper defense against biotic and abiotic stresses.