Analynized On The Seeds Abortion Of Wilted-nut Longan (Dimocarpus Longan Lour.) By CDNA-AFLP

In longan (Dimocarpus Longan Lour.) production, the size of fruits is an important factor influencing quality. However, mostly all of existing cultivars are big seeds, thin pulp and low edible rate that can't meet the raw-eaten oriented development trend of longan. So the research on the mechanism of longan seeds abortion, not only offer theory support for cultivating new improved varieties, but also has significant value in production. cDNA-AFLP (cDNA amplified fragment length polymorphism) analysis was used in this research to find the differentially expressed fragments, closely relating to longan seeds abortion, and lay the molecular foundation for the future research on longan seeds abortion.Longan normal seeds and abortion seeds were selected as the research materials. Total RNA were extracted respectively, then reverse-transcribed and analyzed by cDNA-AFLP. In this study, double-strained cDNA was digested by EcoR I and Mse I, then ligated by corresponding adaptors. Pre-amplification with pre-amplifying primers, then diluted 100 fold as a template used for selective amplification with 64 primers combination. Selective amplification products were separated on a polyacrylamide gel for fingerprint analysis.After analysis, 11 differentially expressed fragments were obtained. Homology searching of Nucleotide sequences and translated sequences were performed with the BLAST sequence alignment program at the web servers of NCBI. 5 sequences showed a high homology, while other 6 sequences showed a low homology. 3 of these 5 high homology sequences were speculatively related to longan seeds abortion, named TDF2 (Calcium ATPase gene), TDF5 (cellulose gene), and TDF7 (plastidic ATP/ADP transporter). The expression of TDF2 and TDF7 were down-regulated in the abortion seeds, while TDF5 was up-regulated. The down-regulated expression of Calcium ATPase directly led to an accumulation of Ca2+ in cytoplasm which may disrupt the energy metabolism and many physiology functions, and even cause the produce of oxygen free radical, even result in the cell death. The up-regulated expression of cellulose gave rise to a degradation of cell wall, naked protoplasts, collapse of cell structure and inclusion. The down-regulated expression of plastidic ATP/ADP transporter, may affect the synthesis of starch in plastid and other important metabolic pathways. The above-mentioned reasons may bring about the seeds abortion in Logan.