Temperature is one of the key factors that influence cotton fiber synthesis at the late growth stage of cotton. In this paper, using two early-maturing cotton varieties as experimental materials, night temperature inc...Temperature is one of the key factors that influence cotton fiber synthesis at the late growth stage of cotton. In this paper, using two early-maturing cotton varieties as experimental materials, night temperature increase was stimulated in the field using far-infrared quartz tubes set in semi-mobile incubators and compared with the normal night temperatures （control） in order to investigate the effects of night temperature on the cotton fiber cellulose synthesis during secondary wall thickening. The results showed that the activity of sucrose synthase （SuSy） and sucrose phosphate synthase （SPS） quickly increased and remained constant during the development of cotton fiber, while the activity of acid invertase （AI） and alkaline invertase （NI） decreased, increased night temperatures prompted the rapid transformation of sugar, and all the available sucrose fully converted into cellulose. With night temperature increasing treatment, an increase in SuSy activity and concentration of sucrose indicate more sucrose converted into UDPG （uridin diphosphate-glucose） during the early and late stages of cotton fiber development. Furthermore, SPS activity and the increased concentration of fructose accelerated fructose degradation and reduced the inhibition of fructose to SuSy; maintaining higher value of allocation proportion of invertase and sucrose during the early development stages of cotton fiber, which was propitious to supply a greater carbon source and energy for cellulose synthesis. Therefore, the minimum temperature in the nightime was a major factor correlated with the activity of sucrose metabolism enzymes in cotton fiber. Consequently, soluble sugar transformation and cellulose accumulation were closely associated with the minimum night temperature.展开更多
Sucrose synthases(SUS) are a family of enzymes that play pivotal roles in carbon partitioning, sink strength and plant development. A total of 11 SUS genes have been identified in the genome of Malus domestica(Md SUSs...Sucrose synthases(SUS) are a family of enzymes that play pivotal roles in carbon partitioning, sink strength and plant development. A total of 11 SUS genes have been identified in the genome of Malus domestica(Md SUSs), and phylogenetic analysis revealed that the Md SUS genes were divided into three groups, named as SUS I, SUS II and SUS III, respectively. The SUS I and SUS III groups included four homologs each, whereas the SUS II group contained three homologs. SUS genes in the same group showed similar structural characteristics, such as exon number, size and length distribution. After assessing four different tissues, Md SUS1 s and Md SUS2.1 showed the highest expression in fruit, whereas Md SUS2.2/2.3 and Md SUS3 s exhibit the highest expression in shoot tips. Most Md SUSs showed decreased expression during fruit development, similar to SUS enzyme activity, but both Md SUS2.1 and Md SUS1.4 displayed opposite expression profiles. These results suggest that different Md SUS genes might play distinct roles in the sink-source sugar cycle and sugar utilization in apple sink tissues.展开更多
In plants, sucrose synthase (SUS) enzymes catalyze conversion of sucrose into fructose and UDP-glucose in the presence of UDP. To investigate the impact of overexpression of heterologous SUS on the growth and developm...In plants, sucrose synthase (SUS) enzymes catalyze conversion of sucrose into fructose and UDP-glucose in the presence of UDP. To investigate the impact of overexpression of heterologous SUS on the growth and development of Arabidopsis, we transformed Arabidopsis plants with an overexpression vector containing an aspen SUS gene (PtrSUS1). The genomic PCR confirmed the successful integration of PtrSUS1 transgene in the Arabidopsis genome. PtrSUS1 expression in transgenic Arabidopsis plants was confirmed by RT-PCR. The SUS activity was dramatically increased in all transgenic lines examined. The three selected transgenic PtrSUS1 lines exhibited faster growth and flowered about 10 days earlier compared to untransformed controls, and also possessed 133%, 139%, and 143% SUS activity compared to controls. Both fresh weights and dry biomass yields of the whole plants from these three selected transgenic lines were significantly increased to 125% of the controls. Transgenic PtrSUS1 lines also had a higher tolerance to higher concentration of sucrose which was reflective of the increased SUS activity in transgenic versus wild-type plants. The growth differences between wild-type and transgenic plants, either in root and hypocotyl length or in fresh and dry weight of whole plant, became more pronounced on the media containing higher sucrose concentrations. Taken together, these results showed that the early flowering, faster growth and increased tolerance to higher sucrose in transgenic lines were caused by the genome integration and constitutive expression of the aspen PtrSUS1 gene in transgenic Arabidopsis.展开更多
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education,China(20070759002)the Key Technologies R&D Program of China during the 11th Five-Year Plan period(2006BAD21B02)
文摘Temperature is one of the key factors that influence cotton fiber synthesis at the late growth stage of cotton. In this paper, using two early-maturing cotton varieties as experimental materials, night temperature increase was stimulated in the field using far-infrared quartz tubes set in semi-mobile incubators and compared with the normal night temperatures （control） in order to investigate the effects of night temperature on the cotton fiber cellulose synthesis during secondary wall thickening. The results showed that the activity of sucrose synthase （SuSy） and sucrose phosphate synthase （SPS） quickly increased and remained constant during the development of cotton fiber, while the activity of acid invertase （AI） and alkaline invertase （NI） decreased, increased night temperatures prompted the rapid transformation of sugar, and all the available sucrose fully converted into cellulose. With night temperature increasing treatment, an increase in SuSy activity and concentration of sucrose indicate more sucrose converted into UDPG （uridin diphosphate-glucose） during the early and late stages of cotton fiber development. Furthermore, SPS activity and the increased concentration of fructose accelerated fructose degradation and reduced the inhibition of fructose to SuSy; maintaining higher value of allocation proportion of invertase and sucrose during the early development stages of cotton fiber, which was propitious to supply a greater carbon source and energy for cellulose synthesis. Therefore, the minimum temperature in the nightime was a major factor correlated with the activity of sucrose metabolism enzymes in cotton fiber. Consequently, soluble sugar transformation and cellulose accumulation were closely associated with the minimum night temperature.
基金supported in part by the National Natural Science Foundation of China (31372038)the Natural Basic Research Plan in Shaanxi Province of China (2015JQ3082)
文摘Sucrose synthases(SUS) are a family of enzymes that play pivotal roles in carbon partitioning, sink strength and plant development. A total of 11 SUS genes have been identified in the genome of Malus domestica(Md SUSs), and phylogenetic analysis revealed that the Md SUS genes were divided into three groups, named as SUS I, SUS II and SUS III, respectively. The SUS I and SUS III groups included four homologs each, whereas the SUS II group contained three homologs. SUS genes in the same group showed similar structural characteristics, such as exon number, size and length distribution. After assessing four different tissues, Md SUS1 s and Md SUS2.1 showed the highest expression in fruit, whereas Md SUS2.2/2.3 and Md SUS3 s exhibit the highest expression in shoot tips. Most Md SUSs showed decreased expression during fruit development, similar to SUS enzyme activity, but both Md SUS2.1 and Md SUS1.4 displayed opposite expression profiles. These results suggest that different Md SUS genes might play distinct roles in the sink-source sugar cycle and sugar utilization in apple sink tissues.
文摘In plants, sucrose synthase (SUS) enzymes catalyze conversion of sucrose into fructose and UDP-glucose in the presence of UDP. To investigate the impact of overexpression of heterologous SUS on the growth and development of Arabidopsis, we transformed Arabidopsis plants with an overexpression vector containing an aspen SUS gene (PtrSUS1). The genomic PCR confirmed the successful integration of PtrSUS1 transgene in the Arabidopsis genome. PtrSUS1 expression in transgenic Arabidopsis plants was confirmed by RT-PCR. The SUS activity was dramatically increased in all transgenic lines examined. The three selected transgenic PtrSUS1 lines exhibited faster growth and flowered about 10 days earlier compared to untransformed controls, and also possessed 133%, 139%, and 143% SUS activity compared to controls. Both fresh weights and dry biomass yields of the whole plants from these three selected transgenic lines were significantly increased to 125% of the controls. Transgenic PtrSUS1 lines also had a higher tolerance to higher concentration of sucrose which was reflective of the increased SUS activity in transgenic versus wild-type plants. The growth differences between wild-type and transgenic plants, either in root and hypocotyl length or in fresh and dry weight of whole plant, became more pronounced on the media containing higher sucrose concentrations. Taken together, these results showed that the early flowering, faster growth and increased tolerance to higher sucrose in transgenic lines were caused by the genome integration and constitutive expression of the aspen PtrSUS1 gene in transgenic Arabidopsis.
