The Cloning And Expression Analysis Of TFL1 And SOC1 Homolog Genes In Rosaceae

There are a wide variety of plants in Rosaceae, many are of economic importance. Plants will bloom at a predetermined time when people apply various techniques to regulate their flowering time for higher ornamental value and application value. In this study, TFL1(TERMINAL FLOWER 1) and SOC1 (SUPRESSOR OF OVEREXPRESSION OF CONSTANS1) homolog genes from seven species in the Rosaceae were cloned respectively. The expression of many TFL1 and SOC1 genes was analyzed and the over-expression vectors were constructed. The main results were as follows:1. We isolated the TFL1 homolog genes from seven species in the Rosaceae by Tail-PCR strategies. The PmTFLl gene was obtained from Prunus mume; RhTFLl was cloned from Rosa hybrida; FaTFL1 gene was obtained from Fragaria ananassa; PsTFL1 gene was cloned from Photinia serrulata; ScTFLl gene was isolated from Spiraea cantoniensis; PfTFL1 gene was obtained from Pyracantha fortuneana; PyTFL1 gene was cloned from Prunus yedoensis. At the same time, we obtained SOC1 homolog genes from six species in the Rosaceae:PmSOC1 gene in Prunus mume; RhSOCl gene in Rosa hybrida; FaSOC1 gene in Fragaria ananassa; PsSOCl gene in Photinia serrulata; ScSOC1 gene in Spiraea cantoniensis; PySOCl gene in Prunus yedoensis.2. The deduced amino acid sequences of TFL1 homologues in Rosaceae were aligned with other TFL1 sequences. We found the TFL1 genes had high identities with each other, consisting of four exons and three introns, two critical sites:His88 and Aspl44. According to the phylogenetic analysis, the TFL1 proteins were classified into two distinct groups:CEN-like group and TFL1-like group. The RhTFL1 belonged to the CEN-like group members, while the other six TFL1 proteins belonged to the TFL1-like group, which show the highest similarity with other plants in Rosaceae.The deduced amino acid sequences of SOC1 homologues in Rosaceae were aligned with other SOC1 sequences. SOC1 genes belong to the MIKC-type MADS-box gene family, having a typical structure of conserved MADS domain,I domain, K domain and C domain. The result showed that SOC1 genes were high identities with each other, consisting of seven exons. In the last exon, there was a highly conserved sequence "DVETELFIGP". The phylogenetic analysis showed that SOC1 homologous proteins in Rosaceae were clustered together.3. Five oversexpression vectors of TFL1 homolog genes were constructed in this study. The pCAMBIA2300s-RhTFL1c was obtained containing pCAMBIA2300s vector and cDNA fragment in Rosa hybrida. The PMV-PmTFL1c vector and PMV-PmTFL1g vector were respectively constructed with cDNA and gDNA in Prunus mume, the PMV-FaTFL1c and PMV-FaTFL1g were respectively constructed with cDNA and gDNA in Fragaria ananassa. Three overexpression vectors of SOC1 homolog genes were obtained:PMV-PmSOC1c, PMV-RhSOC1c and PMV-FaSOC1c. And these eight vectors were transformed into agrobacterium EHA105.4. Expression analysis with semi-quantitative RT-PCR in Prunus mume, Rosa hybrida and Fragaria ananassa showed that TFL1 were inflorescence meristem specific genes, expressing mainly in apical meristem. It was expressed at low level in the early stages of vegetative growth; then expressed at high level in the inflorescence meristem, and highly expressed in apical buds, then gradually decreasing from late June to late August. In contrast, the expression domain of the SOC1 gene was more widespread. It was expressed in both vegetative and reproductive tissues, this gene was highly expressed in vegetative tissues and weakly expressed in floral organs.