Significant Difference In Starch Content Research Articles

Cloning and gene function of dicarboxylate-tricarboxylate carrier protein in Gastrodia elata

The gene GeDTC encoding the dicarboxylate-tricarboxylate carrier protein in Gastrodia elata was cloned by specific primers which were designed based on the transcriptome data of G. elata. Bioinformatics analysis on GeDTC gene was carried out by using ExPASY, ClustalW, MEGA, etc. Positive transgenic plants and potato minituber were obtained by virtue of the potato genetic transformation system. Agronomic characters, such as size, weight, organic acid content, and starch content, of potato minituber were tested and analyzed and GeDTC gene function was preliminarily investigated. The results showed that the open reading frame of GeDTC gene was 981 bp in length and 326 amino acid residues were encoded, with a relative molecular weight of 35.01 kDa. It was predicted that the theoretical isoelectric point of GeDTC protein was 9.83, the instability coefficient was 27.88, and the average index of hydrophilicity was 0.104, which was indicative of a stable hydrophilic protein. GeDTC protein had a transmembrane structure and no signal peptide and was located in the inner membrane of mitochondria. The phylogenetic tree showed that GeDTC was highly homologous with DTC proteins of other plant species, among which GeDTC had the highest homology with DcDTC(XP＿020675804.1) in Dendrobium candidum, reaching 85.89%. GeDTC overexpression vector pCambia1300-35Spro-GeDTC was constructed by double digests, and transgenic potato plants were obtained by Agrobacterium-mediated gene transformation. Compared with the wild-type plants, transgenic potato minituber harvested by transplanting had smaller size, lighter weight, lower organic acid content, and no significant difference in starch content. It is preliminarily induced that GeDTC is the efflux channel of tricarboxylate and related to the tuber development, which lays a foundation for further elucidating the molecular mechanism of G. elata tuber development.

Transcriptome Analysis Reveals the Accumulation Mechanism of Starch in Chinese Yam (Dioscorea opposite Thunb.) Tubers Using RNA-Seq and Iso-Seq

The starch composition of tubers affects the quality and yield of yam, and it is of great significance to deeply investigate the mechanism of starch accumulation in yam. In this study, two yam varieties with significant differences in starch content, Bikeqi (Dioscorea opposita Bikeqi) and Dahechangyv (Dioscorea opposita Dahechangyu), were used as materials. The transcriptome of tubers from seven developmental stages were sequenced using RNA-seq and Iso-seq. Differential genes closely contacted with the metabolism of starch and sucrose were screened and the functions were analysed. The results showed that, the starch content of the two yam varieties reached the maximum at 150 and 165 days respectively, and their difference was the largest at 150 days. Total 21623 unigenes were annotated, and 8378 differential genes were identified within varieties by comparing each developmental stage with the beginning of tuber expansion (90 days), respectively. A total of 5177 differential genes were identified in two varieties in the same period. GO and KEGG were used to analyze these differential genes, a variety of key genes closely related to starch and sucrose metabolism were screened. These results help us to better understand the mechanism of starch accumulation in yam.

Effect of sowing time, seed rate and harvesting duration on quality of Ashwagandha Withania somnifera

The experiment was carried out at Herbal garden, Rajendranagar, Hyderabad during the 2009-10. The experiment was laid out in Completely Randomized Block Design with factorial concept comprising a total of 18 treatments replicated thrice with two sowing dates (August 15th and August 30th), three seed rates (10 kg/ha, 12 kg/ha and 14 kg/ha) and three harvesting durations (150 DAS, 180 DAS and 210 DAS). The data indicated that fresh root yield (13.91 q/ha) and dry root yield (3.38 q/ha) were maximum in August 15th sown crop when compared to August 30th crop. Among the harvesting durations, H3 (210 DAS) recorded maximum fresh root yield (13.48 q/ha) and dry root yield (3.12 q/ha). Among the three way interactions, maximum fresh root yield (15.63 q/ha) and dry root yield (4.40 q/ha) were recorded with August15th sown crop with a seed rate of 12 kg/ha and harvesting duration of 210 DAS (D1S2H3). There was significant difference in starch content due to dates of sowing. Significantly maximum starch content (11.81%) was recorded in D2 (August 30th) followed by D1 (August 15th) recording 11.64%. Reducing sugars were reported to be maximum (2.89%) in August 30th sown crop when compared to August 15th crop. Among the seed rates, S1 (10 kg/ha) recorded maximum reducing sugars (3.26%). Among the harvesting durations, H3 (210 DAS) recorded maximum reducing sugars (3.25%). Maximum non- reducing sugars (7.70%) was recorded in August 30th sown crop when compared to August 15th crop. Among the harvesting durations, H3 (210 DAS) recorded maximum non reducing sugars (7.70%). Among the three way interactions, maximum non reducing sugars (7.78%) was recorded with August 30th sown crop with a seed rate of 12 kg/ha and harvesting duration of 210 DAS (D2S2H3).

Non-structural carbohydrates characteristics of different forest layers in monsoon broad-leaved evergreen forest in Pu'er, Yunnan Province, China

Based on cluster analysis of species vertical stratification, the variations in concentration, allocation and seasonal dynamics of non-structural carbohydrates were investigated in a monsoon broad-leaved evergreen forest in Pu'er, Yunnan Province. The results showed that the concentrations of soluble sugar (3.9%) and nonstructural carbohydrates (NSC, 13.3%) were the highest in the sub-canopy. In contrast, the sugar/starch (0.76) of understory was the lowest. There was no significant difference in starch content among three forest layers. For all forest stories, the soluble sugar was mainly allocated to leaves and the roots had more starch and NSC. The soluble sugar contents in leaves and trunks of sub-canopy species were higher than canopy and understory species. There were no significant differences in soluble sugar content of twigs and roots among three different forest layers. The starch content of leaves increased with decreasing height of forest layers. In contrast, the lowest starch content (10.7%) of roots was in understory. There was no significant difference in starch content of twigs and trunks among three different forest layers. The NSC content of leaves was lower in canopy (10.7%) than that in sub-canopy (12.3%) and understory (12.0%). The lowest NSC content of roots was in understory (14.2%). The lowest sugar/starch of leaves, twigs, and trunks presented in understory, while the lowest sugar/starch of roots presented in canopy (0.79). There were dramatic seasonal variations in concentrations and components of NSC. The concentration of soluble sugar and the sugar/starch were higher in the rainy season than that in the dry season. However, the concentration of starch and NSC were higher in the dry season than in the rainy season. The variations in concentration of NSC and its components among forest layers indicated that species with different heights varied in their utilization strategies of carbon, which partly explained species coexistence.

Two β-amylase genes, OsBAM2 and OsBAM3, are involved in starch remobilization in rice leaf sheaths

To identify mechanisms of starch degradation in rice leaf sheaths at the post-heading stage, we investigated the function of OsBAM2 and OsBAM3, which encode plastid-targeted active β-amylase isoforms, in starch remobilization in leaf sheaths. The starch content in the second leaf sheaths below the flag leaf (the third leaf sheaths) peaked at the flag leaf emergence stage and gradually decreased until 15 days after heading. The mRNA levels of OsBAM2 and OsBAM3 in the third leaf sheaths increased from the flag leaf emergence stage to the heading stage when the starch content began to decrease. However, these mRNA levels did not always remain high during post-heading. Overexpression of OsBAM2 or OsBAM3 markedly repressed starch accumulation in the third leaf sheaths, showing that OsBAM2 and OsBAM3 function in starch degradation in rice leaf sheaths. In contrast, no significant differences in starch content in the third leaf sheaths were detected between knockdown plants of OsBAM2 or OsBAM3 and non-transgenic wild-type plants. Our results suggest that reduced expression of the individual genes, OsBAM2 or OsBAM3, does not result in excess accumulation of starch in the leaf sheaths, probably because of the complementary function of another gene or the action of other genes encoding starch-degrading .

Physicochemical and antioxidant composition of fresh peach palm (Bactris gasipaes Kunth) fruits in Costa Rica

Summary The variability of the physicochemical composition, carotenoid and polyphenol contents and hydrophilic antioxidant capacity of fresh peach palm (Bactris gasipaes) fruit was studied with a view to its exploitation as a potential source of bioactive compounds. The variability present in five batches of peach palm fruit obtained from two regions in Costa Rica: Tucurrique (T) and Pérez Zeledón (PZ), was studied. Significant differences were found for fruit weight, length and width amongst the batches studied. The moisture, fat and protein contents of the Tucurrique fruit were significantly lower than those from Pérez Zeledón. No significant difference in starch content was found between any of the batches of peach palm fruit studied. In terms of antioxidant compounds, the total carotenoid content ranged between 109 and 202 µg β-carotene equivalents/g dry weight (dw), while the total polyphenol content varied from 54 to 106 mg gallic acid equivalents (GAE) /100 g (dw). Both these components presented variability amongst the five batches. The antioxidant capacity was determined by the ORAC method and only the PZ 3 sample presented significant differences from the other four batches. The average hydrophilic antioxidant capacity was 37 ± 7 µmol of Trolox equivalents (TE)/g (dw). Overall, the peach palm fruit showed potential to be used in the development of functional foods since the variability of the raw peach-palm fruit, determined by applying a principal component analysis, showed that some characteristics of this fruit were not affected by harvest time and showed no differences between the batches from the two areas.

CARBOHYDRATE METABOLISM IN INFLORESCENCES OF EPIDENDRUM IBAGUENSE

The purpose of this work was to determine changes in the carbohydrate content and sucrolytic activity in flower structures of Epidendrum ibaguense. Inflorescences were harvested at the different stages of development: 0 – mature closed bud, 1 – fully opened flower, 2 – senescence onset (red petals and twisted red labellum), 3 – wilted and senescent flower. Levels of total soluble sugar, reducing and non-reducing sugars and starch, as well as acid and alkaline invertase and sucrose synthase activities were determined. In inflorescences at the stage 3 the consumption of carbohydrates was observed during their postharvest life, as both carbohydrate types decreased along with time. The levels of soluble sugars, non-reducing sugars and starch did not differ over time in the inflorescence at stages 0, 1 and 2. Reducing sugar content decreased in flowers at stages 0, 1 and 3. No significant difference in starch content was detected among stages 0 to 2; starch showed an increase in senescing flowers. Soluble acid invertase was the main enzyme active throughout flower ageing. Sucrose synthase activity was kept low, with a relative increasing during senescence, which coincided with the highest levels of starch. In conclusion, carbohydrate metabolism varied along with the stage of development and the postharvest life of inflorescences of E. ibaguense.

Translocation of 14C, carbohydrate content and activity of the enzymes of sucrose metabolism in rose petals temperatures

Both export of 14C from the source leaves of roses (Rosa×hybrida cv. Golden Times) and import of 14C to the petals were reduced by plant exposure to low night temperature. However, the import was affected to a greater extent than the export. During all stages of flower bud development the concentration of reducing sugars in petals of roses grown at reduced night temperature was lower than in petals of plants grown at higher night temperature. There was no significant difference in starch content in response to the night temperature, and the content of starch decreased toward complete flower bud opening. The concentration of sucrose in flowers at the low night temperature remained low during all stages of flower bud development, while at the high night temperature the concentration of sucrose increased during flower bud development, reaching a peak at the stage when petals start to unfold. At both temperatures the concentration of sucrose declined at complete flower opening. The activity of sucrose synthase (EC 2.4.1.14) was inhibited by low temperature in young rose shoots more than in the petals, while the activity of acid invertase (EC 3.2.1.26) was affected similarly in both tissues by the temperature treatments.