Studies on phylogenetic and fruit ripening-related genes of guava and sugar apple in Taiwan
Date Issued
2008
Date
2008
Author(s)
Chen, Tseng-Wei
Abstract
Guava and sugar apple are important fruit trees in Taiwan. Red-flesh guava is mostly distributed in indigenous tribes in Taiwan and has valuable application in traditional medicine. Due to the various varieties of red-flesh guava and adulteration problems in fruit materials, a systematic way for classification using molecular marker is necessary to guarantee materials’ reliability and safety. Same manner in sugar apple, there are numerous cultivars and species due to breeding for fruit improvement, thus, reliable molecular detection method is urged for rapidly screening and maintenance of species quality.n the first part, ribosomal DNA 18S, ITS1 and chloroplast DNA trnL intron and trnL-trnF IGS were used for the identification of guava and sugar apple samples. The results were calculated by algorithm NJ, PA, ML and UPGMA. The results showed similarity in each DNA regions. Analysis of uncultivated guavas’ rDNA 18S marker revealed a correlation with their geographical distribution in tribes. In addition, molecular marker of indigenous guava was found different from commercial cultivars, it also reflect differences on altitude and latitude, and red and white-flesh guava. In term of sugar apple, the results showed that cpDNA trnL-trnF IGS was agreeable to morphological classification and suitable for identifying different species and cultivars sugar apples.n the second part, the ripening gene of red-flesh guava and atemoya were identified and characterized. The partial cell wall degradation related genes, PgPG of guava and AtPG of atemoya, were 346 and 351 bp and the deduced amino acid sequences were 115 and 116 in length, respectively. The PgPG and AtPG deduced amino acid aligned with others have an uncompleted OFR and four highly conserved regions that with catalytic sites Gly-His-Gly (GHG) and Tyr residue. On the other hand, PgACO, a ACC oxidase gene from red-flesh guava was 729 bp with 242 deduced amino acids. The alignment of PgACO showed seven conserved regions. There are 9 conserved amino acid residues belongs to dioxygenase, Fe (II) ascorbate family. The expression of PgACO was induced by ethylene. ACC synthase gene (AtACS) of atemoya was 990 bp with a 323 deduced amino acids. Eight amino acid residues in seven conserved regions were correlated with aminotransferase. TNP domain of conserved region was a key site for activity of ACC synthase.n the third part, the ripening-related gene expression of red-flesh guava and atemoya were studied by real-time PCR. PgPG and PgACO were induced by ethylene and firmness loss rate of fruit increased while PG activity was high. The skin color of Red-flesh guava turned yellow as high transcription level of PgACO was detected during ripening from 2nd day to 4th day. AtPG was correlated with the rate of fruit soften, and AtACS induced ACC synthase for ethylene production during fruit ripening. The established molecular detection system, and identified ripening-related gene of guava and sugar apple would be useful for further application in cultivation, postharvest and processing.
Subjects
guava
sugar apple
RAPD
polygalacturonase
ACC synthase
ACC oxidase
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-97-D92628008-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):2ba726b7e5ec3dab801bf1008e95725b