Cloning And Expression Analysis Of Sucrose Synthase Genes In Triticum Polonicum L.

As the end products of photosynthesis, sucrose is of great indispensability in plant growth and functional development. Sucrose involves in the regulation of growth, divergence and grain maturation in crop, which sucrose synthase (SUS) take participate in. SUS catalyze the reversible reaction Sucrose+UDP(?) UDP-glucose+ fructose. SUS is considered as an enzyme has dual character involved in either signal pathway by sucrose biosynthesis or metabolism downstream by sucrose cleavage, respectively. Sucrose gene family is a multiple gene family, transcripts of members in this multigene family in crop are detected in different organs as well as different stages, which indicated that sucrose synthase is involved in growth and development in plant.Polish wheat (Triticum polonicum L.,2n=28, AABB) is a cultivated tetraploid emmer with prominent excellences of big grain and high protein content, which is an important genetic resources in wheat breeding. Dwarfing polish wheat is a unique accession of polish wheat found in Xinjiang, China. It is characterized as dwarfing, more length of spike, more spikelets per spike and more tillers.In this study, the pollen viability of polish wheat and dwarfing polish wheat was researched by TTC method,3 SUS genes was acquired in polish wheat and dwarfing polish wheat by PCR and the expression pattern in different organs as well as different stages of them was detected by RT-PCR. The result was obtained and listed below:1. There are no statistically significant differences were found in pollen viability and fructification rate of polish wheat and dwarfing polish wheat, respectively.2. Three cDNA sequences of SUS gene family in polish wheat was cloned, and a novel SUS gene TpSUS3 was obtained from dwarfing polish wheat. The result of phylogeny analysis and sequence alignment indicated that there is a low identity between TpSUS3 and homologous gene in common wheat, but a high identity of HvSUS3 in Hordeum vulgare L., which is distributed in the clade SUSâ…¡ group.On the other hand, there is a relatively high indetity among TaSUS2 in wheat, TpSUS2dand TpSUS2h which are obtained from dwarfing polish wheat and polish wheat, respectively, which result in their distribution into group SUSI.3. The specific expression of TpSUS3 in dwarfing polish wheat indicated that TpSUS3 is a specifically novel gene in dwarfing polish wheat. The expression concentrated in the early period of sink tissue, its expression levels are relatively low in advanced period of vegetative growth and entire reproductive growth; TpSUS2d is ubiquitously expressed in the entire growth stage of dwarfing polish wheat, the highest expression level is detected in culm of elongation stage and spikelet of booting stage. The expression of TpSUS2h concentrated in culm of elongation stage and leaf of booting stage. There is of possibility that the different expression pattern of TpSUS2d and TpSUS2h in booting stage result in the distribution of fructification rate of polish wheat and dwarfing polish wheat.