Functional Characterization of SlSAHH2 in Tomato Fruit Ripening

Abstract SlSPL-CNR, an SBP-box transcription factor (TF) gene residing at the epimutant Colourless non-ripening (Cnr) locus, is involved in tomato ripening. This epimutant provides a unique model to investigate the (epi)genetic basis of fruit ripening. Here we report that SlSPL-CNR is a nucleus-localized protein with a distinct monopartite nuclear localization signal (NLS). It consists of four consecutive residues ‘ 30KRKR33’ at the N-terminus of the protein. Mutation of the NLS abolishes SlSPL-CNR’s ability to localize in the nucleus. SlSPL-CNR comprises two zinc-finger motifs (ZFMs) within the C-terminal SBP-box domain. Both ZFMs contribute to zinc-binding activity. SlSPL-CNR can induce cell death in tomato and tobacco, dependent on its nuclear localization. However, the two ZFMs have differential impacts on SlSPL-CNR’s induction of severe necrosis or mild necrotic ringspot. NLS and ZFM mutants cannot complement Cnr fruits to ripen. SlSPL-CNR interacts with SlSnRK1. Virus-induced SlSnRK1 silencing leads to reduction in expression of ripening-related genes and inhibits ripening in tomato. We conclude that SlSPL-CNR is a multifunctional protein that consists of a distinct monopartite NLS, binds to zinc, and interacts with SlSnRK1 to affect cell death and tomato fruit ripening.

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Characterization of Tomato Fruit LeRIN Gene Application Virus-Induced Gene Silencing Technology

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.781-784.1685 ◽

2013 ◽

Vol 781-784 ◽

pp. 1685-1688

Author(s):

Ling Li ◽

Guo Xia Zhu ◽

Zheng Liu ◽

Tie Ling Liu

Keyword(s):

Gene Silencing ◽

Fruit Ripening ◽

Tomato Fruit ◽

Specific Gene ◽

Virus Induced Gene Silencing ◽

Green Color ◽

Tomato Fruit Ripening ◽

Infiltration Method ◽

I Gene

Virus-induced gene silencing (VIGS) is a powerful tool for the study of gene function and down regulate specific gene expression in plant. The RIN transcription factor is an important developmental regulator in tomato fruit ripening. In this work, the TRV-LeRIN infiltrated fruit significantly developed green color phenotypes, whereas the control fruit would turn red normally. Dissection of silenced areas for analysis identified whether the LeRIN gene is silenced or not. Taken together, we successfully applied syringe infiltration method of VIGS to silence the LeRIN gene in tomato fruit. These results are critical for understanding the mechanism of tomato fruit ripening.

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681 PB 195 MOLECULAR CHARACTERIZATION OF A cDNA THAT ENCODES 5-AMINOLEVULINIC ACID DEHYDRATASE IN TOMATO

HortScience ◽

10.21273/hortsci.29.5.530d ◽

1994 ◽

Vol 29 (5) ◽

pp. 530d-530

Author(s):

Gary F. Polkinz ◽

David J. Hannapel ◽

Richard J. Gladon

Keyword(s):

Fruit Ripening ◽

Aminolevulinic Acid ◽

Tomato Fruit ◽

Northern Analysis ◽

Chlorophyll Metabolism ◽

E Coli ◽

Acid Dehydratase ◽

Tomato Fruit Ripening

Tomato fruit ripening is characterized by a decrease in chlorophyll content and an increase in lycopene synthesis. We are interested in the role of chlorophyll metabolism as it relates to tomato fruit ripening. 5-Aminolevulinic acid dehydratase (ALAD) is the first committed enzyme in the chlorophyll biosynthetic pathway, and it catalyzes the conversion of two 5-aminolevulinic acid molecules into porphobilinogen. We have isolated a full-length tomato ALAD cDNA clone from a tomato fruit library. Sequence analysis showed that this tomato ALAD was highly homologous to ALAD found in spinach and pea, and the analysis predicted a protein of 46.8 kDa. Southern analysis indicated that 1 to 3 copies of the ALAD gene are present in the tomato genome. Northern analysis suggested that the gene is expressed constitutively throughout tomato fruit development. Currently, we are subcloning the fragment into an E. coli expression vector in order to obtain protein for antibody production for Western analysis.

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