title: Insights into transcriptional regulation of β-D-N-acetylhexosaminidase, an N-glycan-processing enzyme involved in ripening-associated fruit softening.
abstract: Tomato (Solanum lycopersicum) fruit ripening-specific N-glycan processing enzyme, β-D-N-acetylhexosaminidase (β-Hex), plays an important role in the ripening-associated fruit-softening process. However, the regulation of fruit ripening-specific expression of β-Hex is not well understood. We have identified and functionally characterized the fruit ripening-specific promoter of β-Hex and provided insights into its transcriptional regulation during fruit ripening. Our results demonstrate that RIPENING INHIBITOR (RIN), a global fruit ripening regulator, and ABSCISIC ACID STRESS RIPENING 1 (SlASR1), a poorly characterized ripening-related protein, are the transcriptional regulators of β-Hex. Both RIN and SlASR1 directly bound to the β-Hex promoter fragments containing CArG and C₂₋₃(C/G)A cis-acting elements, the binding sites for RIN and SlASR1, respectively. Moreover, β-Hex expression/promoter activity in tomato fruits was downregulated once expression of either RIN or SlASR1 was suppressed; indicating that RIN and SlASR1 positively regulate the transcription of β-Hex during fruit ripening. Interestingly, RIN could also bind to the SlASR1 promoter, which contains several CArG cis-acting elements, and SlASR1 expression was suppressed in rin mutant fruits, indicating that RIN also acts as a positive regulator of SlASR1 expression during fruit ripening. Taken together, these results suggest that RIN, both directly and indirectly, through SlASR1, regulates the transcription of β-Hex during fruit ripening. The fruit ripening-specific promoter of β-Hex could be a useful tool in regulating gene expression during fruit ripening.
authors.affiliation: National Institute of Plant Genome Research, New Delhi 110067, India.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Irfan
authors.affiliation: National Institute of Plant Genome Research, New Delhi 110067, India.
authors.forename: Sumit
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: National Institute of Plant Genome Research, New Delhi 110067, India.
authors.forename: Vinay
authors.initials: V
authors.lastname: Kumar
authors.affiliation: National Institute of Plant Genome Research, New Delhi 110067, India.
authors.forename: Niranjan
authors.initials: N
authors.lastname: Chakraborty
authors.affiliation: National Institute of Plant Genome Research, New Delhi 110067, India.
authors.forename: Subhra
authors.initials: S
authors.lastname: Chakraborty
authors.affiliation: National Institute of Plant Genome Research, New Delhi 110067, India asis_datta@rediffmail.com asis_datta@nipgr.res.in.
authors.forename: Asis
authors.initials: A
authors.lastname: Datta
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D035264:Flowers / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D005638:Fruit / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D005936:Glucans / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D026161:MADS Domain Proteins / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D018547:Plant Stems / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics; D020798:Two-Hybrid System Techniques; D001619:beta-N-Acetylhexosaminidases / Q000235:genetics* / Q000378:metabolism
chemical_list: D005030:Ethylenes; D005936:Glucans; D026161:MADS Domain Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D000040:Abscisic Acid; D001619:beta-N-Acetylhexosaminidases
keywords: Fruit ripening; RIN; SlASR1; fruit ripening-specific promoter; transcriptional regulation.; β-Hex