The gene regulated in dormant seed of Prunus campanulata during warm stratification
Date Issued
2011
Date
2011
Author(s)
Lu, Chien-Yu
Abstract
Seed dormancy is regulated by complex networks in order to optimize the timing of germination. Although over 5000 publications on seed dormancy have appeared in the past decades, the underlying molecular regulatory mechanisms are not fully understood. Fresh seeds of Formoan cherry (Prunus campanulata Maxim), a popular ornamental tree, are deeply dormant and require warm stratification followed by cold stratification for complete dormancy-breaking. This operation is special to Formoan cherry but not to Arabidopsis. Many studies have revealed the effect of cold stratification on dormancy-breaking, but the effect of warm stratification is unclear. In this study we used the subtractive suppression hybridization (SSH) to study the gene regulation of prunus seeds undergoing warm stratification. Formoan cherry seeds were harvested, cleaned and air-dried for 3 days to reduce the water content to 15% of fresh weight and followed by warm stratification. At the second and seventh days of warm treatment, seed RNAs were extracted for SSH experiments. After constructed the subtraction libraries of second and seventh days against zero day of warm stratification, we performed reverse northern assays to confirm the upregulated and down-regulated genes. Clones obtained from this study were sequenced after removing duplicated clone containing the same length of DNA fragments. Using the website to blast the fragment sequences, we obtained 59 genes were up-regulated and down-regulated that play functions in metabolism, transcription, translation, signal transduction, growth and development, nutrient storage and stress-related. Interestingly, two ABA negative regulators, RACK1 and PP2CA were highly expressed and one positive component, 1-phosphatidylinositol-4- phosphate 5-kinase was repressed. These three regulators could reduce the ABA sensitivity of prunus seeds in the beginning of warm stratification. Moreover, we found that the ABA content was significantly decreased at the seventh days of warm stratification. Taken together, warm stratification treatment alone can not promote the seed germination due to low GA content, but can reduce the ABA sensitivity by expressing ABA negative regulators and repressing positive components in the beginning when ABA content is still high and followed by reduced the ABA content in the seeds.
Subjects
Formoan cherry
seed dormancy
warm stratification
abscisic acid
subtractive suppression hybridization
Type
thesis
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