Abstract
BackgroundThe NAC (NAM, ATAF1/ATAF2, and CUC2) transcription factors belong to a large family of plant-specific transcription factors in monocot and dicot species. These transcription factors regulate the expression of stress tolerance-related genes that protect plants from various abiotic stresses, including drought, salinity, and low temperatures.ResultsIn this study, we identified the CaNAC46 transcription factor gene in Capsicum annuum. Its open reading frame was revealed to comprise 921 bp, encoding a protein consisting of 306 amino acids, with an isoelectric point of 6.96. A phylogenetic analysis indicated that CaNAC46 belongs to the ATAF subfamily. The expression of CaNAC46 was induced by heat, cold, high salt, drought, abscisic acid, salicylic acid, and methyl jasmonate treatments. Thus, CaNAC46 may be important for the resistance of dry pepper to abiotic stresses. A subcellular localization analysis confirmed that CaNAC46 is localized in the nucleus. The overexpression of CaNAC46 improved the tolerance of transgenic Arabidopsis thaliana plants to drought and salt stresses. The CaNAC46-overexpressing lines had longer roots and more lateral roots than wild-type lines under prolonged drought and high salt stress conditions. Additionally, CaNAC46 affected the accumulation of reactive oxygen species (ROS). Moreover, CaNAC46 promoted the expression of SOD, POD, RD29B, RD20, LDB18, ABI, IAA4, and P5CS. The malondialdehyde contents were higher in TRV2-CaNAC46 lines than in wild-type plants in response to drought and salt stresses. Furthermore, the expression levels of stress-responsive genes, such as ABA2, P5CS, DREB, RD22, CAT, and POD, were down-regulated in TRV2-CaNAC46 plants.ConclusionsUnder saline and drought conditions, CaNAC46 is a positive regulator that activates ROS-scavenging enzymes and enhances root formation. The results of our study indicate CaNAC46 is a transcriptional regulator responsible for salinity and drought tolerance and suggest the abiotic stress-related gene regulatory mechanisms controlling this NAC transcription factor are conserved between A. thaliana and pepper.
Highlights
The NAC (NAM, ATAF1/ATAF2, and CUC2) transcription factors belong to a large family of plantspecific transcription factors in monocot and dicot species
Identification of the ATAF subfamily gene CaNAC46 in pepper The NAC transcription factors are involved in mediating plant responses to abiotic stresses [16, 17]
The proportions of basic and acidic amino acids were similar between CaNAC46 and the homologous NAC proteins in other model plants
Summary
The NAC (NAM, ATAF1/ATAF2, and CUC2) transcription factors belong to a large family of plantspecific transcription factors in monocot and dicot species. These transcription factors regulate the expression of stress tolerance-related genes that protect plants from various abiotic stresses, including drought, salinity, and low temperatures. Abiotic stresses, including drought, high-salinity, and temperature extremes, are the main factors responsible for decreased dry pepper quality [3]. The large NAC (NAM, ATAF1/ATAF2, and CUC2) transcription factor family is involved in abiotic stress responses [5]. A genome-wide analysis of 104 NAC transcription factors in hot pepper and an expression analysis of 22 NAC transcription factor genes revealed diverse responses to various stresses [13]. The pepper CaNAC2 transcription level is reportedly considerably up-regulated by an abiotic stress treatment, but is down-regulated by osmotic stress and a salicylic acid (SA) treatment [14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
