“…Among cell wall catabolism enzymes, PG is the most active and paramount agent of fruit aging and cell wall softening. The main role of PG during fruit ripening is pectin hydrolysis, which leads to softening of the fruit (Rao and Paran , Koyama et al , Ahmed et al ). This line of thinking is supported by the finding in tomato plants that high levels of endo‐PG activity in ripe fruits led to fruit softening (Giovannoni et al ).…”
MADS-box transcription factors play important roles in organ development. In plants, most studies on MADS-box genes have mainly focused on flower development and only a few concerned fruit development and ripening. A new MADS-box gene named MaMADS7 was isolated from banana fruit by rapid amplification of cDNA ends (RACE) based on a MADS-box fragment obtained from a banana suppression subtractive hybridization (SSH) cDNA library. MaMADS7 is an AGAMOUS-like MADS-box gene that is preferentially expressed in the ovaries and fruits and in tobacco its protein product localizes to the nucleus. This study found that MaMADS7 expression can be induced by exogenous ethylene. Ectopic expression of MaMADS7 in tomato resulted in broad ripening phenotypes. The expression levels of seven ripening and quality-related genes, ACO1, ACS2, E4, E8, PG, CNR and PSY1 in MaMADS7 transgenic tomato fruits were greatly increased while the expression of the AG-like MADS-box gene TAGL1 was suppressed. Compared with the control, the contents of β-carotene, lycopene, ascorbic acid and organic acid in transformed tomato fruits were increased, while the contents of glucose and fructose were slightly decreased. MaMADS7 interacted with banana 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase gene 1 (MaACO1) and tomato phytoene synthase gene (LePSY1) promoters. Our results indicated that MaMADS7 plays an important role in initiating endogenous ethylene biosynthesis and fruit ripening.
“…Among cell wall catabolism enzymes, PG is the most active and paramount agent of fruit aging and cell wall softening. The main role of PG during fruit ripening is pectin hydrolysis, which leads to softening of the fruit (Rao and Paran , Koyama et al , Ahmed et al ). This line of thinking is supported by the finding in tomato plants that high levels of endo‐PG activity in ripe fruits led to fruit softening (Giovannoni et al ).…”
MADS-box transcription factors play important roles in organ development. In plants, most studies on MADS-box genes have mainly focused on flower development and only a few concerned fruit development and ripening. A new MADS-box gene named MaMADS7 was isolated from banana fruit by rapid amplification of cDNA ends (RACE) based on a MADS-box fragment obtained from a banana suppression subtractive hybridization (SSH) cDNA library. MaMADS7 is an AGAMOUS-like MADS-box gene that is preferentially expressed in the ovaries and fruits and in tobacco its protein product localizes to the nucleus. This study found that MaMADS7 expression can be induced by exogenous ethylene. Ectopic expression of MaMADS7 in tomato resulted in broad ripening phenotypes. The expression levels of seven ripening and quality-related genes, ACO1, ACS2, E4, E8, PG, CNR and PSY1 in MaMADS7 transgenic tomato fruits were greatly increased while the expression of the AG-like MADS-box gene TAGL1 was suppressed. Compared with the control, the contents of β-carotene, lycopene, ascorbic acid and organic acid in transformed tomato fruits were increased, while the contents of glucose and fructose were slightly decreased. MaMADS7 interacted with banana 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase gene 1 (MaACO1) and tomato phytoene synthase gene (LePSY1) promoters. Our results indicated that MaMADS7 plays an important role in initiating endogenous ethylene biosynthesis and fruit ripening.
“…Smith et al (1990) and Wang et al (2000) reported that fruit ripening is a complex, genetically programmed process, involving increases in respiration and ethylene production, changes in color and flavor, and softening. Fischer and Bennett (1991) and Ahmed et al (2011) reviewed that fruit softening is associated with structural changes in the cell wall, including reduction in the size of hemicellulose, loss of galactose side-chains, and solubilization and depolymerization of pectin by the influence of one of the hydrolytic enzymes, polygalacturonase (PG).…”
ABSTRACT. Molecular chaperones of plasmid pBI121 carrying CaMV35S promoter and a nucleotide sequence of plasmid pBI221 were inserted into plasmid pCAMBIA2300 to construct an intermediate vector: pVBG2307. This novel vector pVBG2307 contains a greatly expanded multiple cloning site with an adjacent imported CaMV35S promoter sequence. This vector allows controlled transformation of DNA in both Escherichia coli and Agrobacterium tumefaciens. Cloned PG, orf456, ipt genes and E8, a fruiting promoter, were amplified by PCR of cDNA libraries of Capsicum annum and Lycopersicon esculentum and were then transferred into vector pVBG2307. The viability of this vector was demonstrated, as it regulated PG, orf456, ipt and E8 genes in E. coli and could be transferred into Agrobacterium strain EHA105-4.
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