Expression patterns of cell wall-modifying genes from banana during fruit ripening and in relationship with finger drop

Few molecular studies have been devoted to the finger drop process that occurs during banana fruit ripening. Recent studies revealed the involvement of changes in the properties of cell wall polysaccharides in the pedicel rupture area. In this study, the expression of cell-wall modifying genes was monitored in peel tissue during post-harvest ripening of Cavendish banana fruit, at median area (control zone) and compared with that in the pedicel rupture area (drop zone). To this end, three pectin methylesterase (PME) and seven xyloglucan endotransglycosylase/hydrolase (XTH) genes were isolated. The accumulation of their mRNAs and those of polygalaturonase, expansin, and pectate lyase genes already isolated from banana were examined. During post-harvest ripening, transcripts of all genes were detected in both zones, but accumulated differentially. MaPME1, MaPG1, and MaXTH4 mRNA levels did not change in either zone. Levels of MaPME3 and MaPG3 mRNAs increased greatly only in the control zone and at the late ripening stages. For other genes, the main molecular changes occurred 1–4 d after ripening induction. MaPME2, MaPEL1, MaPEL2, MaPG4, MaXTH6, MaXTH8, MaXTH9, MaEXP1, MaEXP4, and MaEXP5 accumulated highly in the drop zone, contrary to MaXTH3 and MaXTH5, and MaEXP2 throughout ripening. For MaPG2, MaXET1, and MaXET2 genes, high accumulation in the drop zone was transient. The transcriptional data obtained from all genes examined suggested that finger drop and peel softening involved similar mechanisms. These findings also led to the proposal of a sequence of molecular events leading to finger drop and to suggest some candidates

Sequence of AFTP1, a cysteine proteinase from apricot fruit (Accession nø U93166). Gene expression during fruit ripening

url=http://www.tarweed.com/pgr/PGR97-179.htmlInternational audienc

Molecular cloning and nucleotide sequence of a metallothionein-like protein from apricot fruit (Accession nø U97494). Gene expression during fruit ripening

url=http://www.tarweed.com/pgr/PGR97-160.htmlInternational audienc

Sequence of an O-methyltransferase from apricot fruit (Accession nø U82011). Gene expression during fruit ripening

url=http://www.tarweed.com/pgr/PGR97-118.htmlInternational audienc

Antioxidant activity of tropical fruits as related to their polyphenol, vitamin C and carotenoid contents: a review

National audienceToday's consumers are more and more concerned with foods containing components that are providing health benefit, such as polyphenols, vitamins and carotenoids. The contribution of these components to health benefit in plant-derived food has often been related to their antioxidant properties. Most studies on these components in fruits have been carried out in temperate countries. Less is known about them in fruits from tropical areas, whereas the international trading of tropical fruits is developing. This paper summarizes knowledge on polyphenols, vitamin C and carotenoids in tropical fruits in relation to their measured antioxidant activity. Data on the composition of these fruits in vitamins have been recently published. Less information is available on their total phenolic content and their phenolic composition. A statistical analysis including data on various tropical fruits has shown that the correlation coefficient between antioxidant activity and total phenolic content was 0.96. The corresponding coefficient for ascorbic acid amounted 0.23 to 0.35, depending on the method used to measure the antioxidant activity. It is noticeable that in acerola (Malpighia emarginata) and guava (Psidium guajava), which exhibit the highest antioxidant activity, this activity is highly linked to both total phenolic and ascorbic acid contents. Antioxidant activity was shown to be negatively correlated to carotenoid content in guava. However, it is generally not clear which compounds are responsible for the antioxidant properties of tropical fruits, as they have rarely been simultaneously analyzed for their composition in all these components and their antioxidant activity. Moreover, total phenolic, ascorbic acid and carotenoid contents may be highly influenced by cultivars, as suggested in mango and guava pulp. The effects of the development and maturation stages and of postharvest storage conditions on these components and on antioxidant activity in tropical fruits still need to be investigated

Sequence of an allergen-, stress-, and pathogenesis-related protein from apricot fruit (Accession nø U93165). Gene expression during fruit ripening

url=http://www.tarweed.com/pgr/PGR97-180.htmlInternational audienc

Sequence of an O-methyltransferase from apricot fruit (Accession nø U82011). Gene expression during fruit ripening

url=http://www.tarweed.com/pgr/PGR97-118.htmlInternational audienc

Molecular cloning and nucleotide sequence of a Rab 7 small GTP-binding protein from apricot fruit (Accession nø U82219). Gene expression during fruit ripening

url=http://www.tarweed.com/pgr/PGR97-117.htmlInternational audienc

Molecular cloning and nucleotide sequence of an abscisic acid-, stress-, ripening-induced (ASR) -like protein from apricot fruit (Accession nø U93164). Gene expression during fruit ripening

url=http://www.tarweed.com/pgr/PGR97-166.htmlInternational audienc