A novel BSD domain-containing transcription factor controlling vegetative growth, leaf senescence and fruit quality in tomato

Abstract

BSD (mammalian BTF2-like transcription factors, Drosophila synapse-associated proteins and yeast DOS2-like proteins) is a domain existing in a variety of organisms but its function has not been well studied. In this study, we identified a novel BSD domain-containing protein (SlBSD1) in tomato. Biochemical and subcellular assay indicated SlBSD1 is a functional transcription factor and predominantly localized in the nucleus. The genetic analyses suggested that SlBSD1 is a novel negative regulator of vegetative growth and leaf senescence in tomato. The SlBSD1-knockdown tomato plants exhibited retarded vegetative growth and precocious leaf senescence, whereas SlBSD1-overexpression tomato plants displayed the opposite phenotypes. The negative role of SlBSD1 in leaf senescence was also supported by RNA-Seq analysis on the SlBSD1-knockdown tomato leaf in comparison with the wild type tomato leaf. Moreover, altered soluble solids contents in fruits were detected in the SlBSD1-knockdown and SlBSD1-overexpression tomato plants. Taken together, our data suggested that the novel transcription factor SlBSD1 plays important roles in controlling fruit quality and other physiological processes in tomato, including vegetative growth and leaf senescence.