Isolation,Expression And Function Analysis Of SVP-Like Genes In Strawberry

Strawberry, belonging to the perennial herbaceous plants, will come into a dormant state under the low temperature and short day conditions. Illutstration of the mechanisms underlying its dormancy can provide theoretical basis for the management of its facility production. SVP-like genes(SHORT VEGETATIVE PHASE) play an important role in the response of plants to ambient temperature changing and were involved in the regulation of growth and development process.In this study, three homologous gene, of SVP were isolated from strawberry, their spatial and temporal expression profiles were analyzed. Then, following the ectopic expression vectors construct, their ectopic expressions in Arabidopsis were performed respectively to clarify their possible functions. Such works were aimed to lay a foundation for the illutstration of the strawberry SVP homologues and their molecular regulatory mechanisms in dormant process of strawberry. The primary results are as follows:1. Three full-length cDNA sequences of SVP-like homologues were obtained from cultivated strawberry by specific RT-PCR, and named as:FaSVPl, FaSVP2 and FaSVP3 respectively. Among them, the CDS of FaSVP1 and FaSVP2 are 681 bp in length, both encoding 226 amino acids; while the CDS of FaSVP3 is 741 bp in length, encoding 246 amino acids. The encoded proteins are all belonging to MADS-box gene family. The sequences have high homology with other SVP-like homologous genes.2. Expression profiles of FaSVPs were detected. These three genes mainly expressed in dormant vegetative tissues, highest in old leaves, and no expression was detected in flowers, lowly expression of FaSVPl was detected in roots. The expression patterns of FaSVPs in different tissues are consistent. However, their relative expression levels have some differences.3. Their expression changing in the process of dormancy were detected. In both two kinds of varieties with different dormant habits, expression of FaSVPs increases gradually following the proceeding of the dormancy, their highest expression were all detected at the time that the cultivars were in deepest dormancy. Following the releasing of dormancy, their expression levels decreased gradually.4. Effects of gibberellins on the growth recovery of strawberry in dormancy and the expression changing of FaSVPs were also revealed. The application of GA3 can break the dormancy processes of both kinds of strawberry cultivars with the recovering of growth. It was also found that with a higher concentration of GA3, the more obviously effect was detected, the best effect on cultivar’Allstar’was found with the highest GA3 concentration of 12.0 mg/L of this experiment. While for another cultiyar ’Yanli’, whose dormancy habit is not so deeply, a low concentration of GA3 can also resume its growth. Under the treatment of GA3, the expression of FaSVPl would be suppressed in both two kinds of strawberry.5. Transgenic plants ectopic expressing FaSVPs genes in Arabidopsis were got and their phenotypes were analyzed respectively. Compared with the controls, the vegetative growth period of FaSVPl ectopic expressing plants were prolonged slightly, following a delayed flowering time, but the changes of growth habits in transgenic plants ectopic expressing FaSVP2 and FaSVP3 were not obvious. In addition, the inflorescence and floral organs of some of the transgenic lines of the three genes were abnormal.