The potential roles of acid invertase family in Dendrobium huoshanense: Identification, evolution, and expression analyses under abiotic stress.

Dendrobium huoshanense, a traditional Chinese medicine prized for its horticultural and medicinal properties, thrives in an unfavorable climate and is exposed to several adverse environmental conditions. Acid invertase (AINV), a widely distributed enzyme that has been demonstrated to play a significant role in response to environmental stresses. However, the identification of the AINV gene family in D. huoshanense, the collinearity between relative species, and the expression pattern under external stress have yet to be resolved. We systematically retrieved the D. huoshanense genome and screened out four DhAINV genes, which were further classified into two subfamilies by the phylogenetic analysis. The evolutionary history of AINV genes in D. huoshanense was uncovered by comparative genomics investigations. The subcellular localization predicted that the DhVINV genes may be located in the vacuole, while the DhCWINV genes may be located in the cell wall. The exon/intron structures and conserved motifs of DhAINV genes were found to be highly conserved in two subclades. The conserved amino acids and catalytic motifs in DhAINV proteins were determined to be critical to their function. Notably, the cis-acting elements in all DhAINV genes were mainly relevant to abiotic stresses and light response. In addition, the expression profile coupled with qRT-PCR revealed the typical expression patterns of DhAINV in response to diverse abiotic stresses. Our findings could be beneficial to the characterization and further investigation of AINV functions in Dendrobium plants.

[Genotype-Specific Features of Cold-Induced Sweetening Process Regulation in Potato Varieties Nikulinsky, Symfonia, and Nevsky].

In this study, we performed expression analysis of genes associated with cold-induced sweetening in potato tubers: vacuolar invertase (Pain-1), sucrose synthase (SUS4), and invertase inhibitor (InvInh2). Potato varieties Nikulinsky, Symfonia, and Nevsky were used. All three varieties were found to accumulate sugars at low temperatures; the maximum accumulation of reducing sugars was observed at 4°C. It was found that the expression pattern of genes associated with cold-induced sweetening differs depending on the variety and storage duration. The increased expression of vacuolar invertase and its inhibitor is more pronounced at the beginning of storage period, whereas the increased expression of sucrose synthase is more pronounced after 3 months of storage. At early storage periods, high expression of invertase and low expression of inhibitor is observed in the Dutch variety Symfonia, and vice versa in the Russian varieties Nikulinsky and Nevsky. The involvement of the studied genes in the process of cold-induced sweetening is discussed.

An alternative pathway to plant cold tolerance in the absence of vacuolar invertase activity.

To cope with cold stress, plants have developed antioxidation strategies combined with osmoprotection by sugars. In potato (Solanum tuberosum) tubers, which are swollen stems, exposure to cold stress induces starch degradation and sucrose synthesis. Vacuolar acid invertase (VInv) activity is a significant part of the cold-induced sweetening (CIS) response, by rapidly cleaving sucrose into hexoses and increasing osmoprotection. To discover alternative plant tissue pathways for coping with cold stress, we produced VInv-knockout lines in two cultivars. Genome editing of VInv in 'Désirée' and 'Brooke' was done using stable and transient expression of CRISPR/Cas9 components, respectively. After storage at 4°C, sugar analysis indicated that the knockout lines showed low levels of CIS and maintained low acid invertase activity in storage. Surprisingly, the tuber parenchyma of vinv lines exhibited significantly reduced lipid peroxidation and reduced H2 O2 levels. Furthermore, whole plants of vinv lines exposed to cold stress without irrigation showed normal vigor, in contrast to WT plants, which wilted. Transcriptome analysis of vinv lines revealed upregulation of an osmoprotectant pathway and ethylene-related genes during cold temperature exposure. Accordingly, higher expression of antioxidant-related genes was detected after exposure to short and long cold storage. Sugar measurements showed an elevation of an alternative pathway in the absence of VInv activity, raising the raffinose pathway with increasing levels of myo-inositol content as a cold tolerance response.

CRISPR/Cas-mediated knockdown of vacuolar invertase gene expression lowers the cold-induced sweetening in potatoes.

MAIN CONCLUSION: VInv gene editing in potato using CRISPR/Cas9 resulted in knockdown of expression and a lower VInv enzymatic activity resulting in a decrease in post-harvest cold-storage sugars formation and sweetening in potatoes. CRISPR-Cas9-mediated knockdown of vacuolar invertase (VInv) gene was carried out using two sgRNAs in local cultivar of potato plants. The transformation efficiency of potatoes was found to be 11.7%. The primary transformants were screened through PCR, Sanger sequencing, digital PCR, and ELISA. The overall editing efficacy was determined to be 25.6% as per TIDE analysis. The amplicon sequencing data showed maximum indel frequency for potato plant T12 (14.3%) resulting in 6.2% gene knockout and 6% frame shift. While for plant B4, the maximum indel frequency of 2.0% was found which resulted in 4.4% knockout and 4% frameshift as analyzed by Geneious. The qRT-PCR data revealed that mRNA expression of VInv gene was reduced 90-99-fold in edited potato plants when compared to the non-edited control potato plant. Following cold storage, chips analysis of potatoes proved B4 and T12 as best lines. Reducing sugars' analysis by titration method determined fivefold reduction in percentage of reducing sugars in tubers of B4 transgenic lines as compared to the control. Physiologically genome-edited potatoes behaved like their conventional counterpart. This is first successful report of knockdown of potato VInv gene in Pakistan that addressed cold-induced sweetening resulting in minimum accumulation of reducing sugars in genome edited tubers.

Functional characterization and vacuolar localization of fructan exohydrolase derived from onion (Allium cepa).

Fructans such as inulin and levan accumulate in certain taxonomic groups of plants and are a reserve carbohydrate alternative to starch. Onion (Allium cepa L.) is a typical plant species that accumulates fructans, and it synthesizes inulin-type and inulin neoseries-type fructans in the bulb. Although genes for fructan biosynthesis in onion have been identified so far, no genes for fructan degradation had been found. In this study, phylogenetic analysis predicted that we isolated a putative vacuolar invertase gene (AcpVI1), but our functional analyses demonstrated that it encoded a fructan 1-exohydrolase (1-FEH) instead. Assessments of recombinant proteins and purified native protein showed that the protein had 1-FEH activity, hydrolyzing the ß-(2,1)-fructosyl linkage in inulin-type fructans. Interestingly, AcpVI1 had an amino acid sequence close to those of vacuolar invertases and fructosyltransferases, unlike all other FEHs previously found in plants. We showed that AcpVI1 was localized in the vacuole, as are onion fructosyltransferases Ac1-SST and Ac6G-FFT. These results indicate that fructan-synthesizing and -degrading enzymes are both localized in the vacuole. In contrast to previously reported FEHs, our data suggest that onion 1-FEH evolved from a vacuolar invertase and not from a cell wall invertase. This demonstrates that classic phylogenetic analysis on its own is insufficient to discriminate between invertases and FEHs, highlighting the importance of functional markers in the nearby active site residues.

The amounts and ratio of nitrogen and phosphorus addition drive the rate of litter decomposition in a subtropical forest.

Nitrogen (N) and phosphorus (P) control biogeochemical cycling in terrestrial ecosystems. However, N and P addition effects on litter decomposition, especially biological pathways in subtropical forests, remain unclear. Here, a two-year field litterbag experiment was employed in a subtropical forest in southwestern China to examine N and P addition effects on litter biological decomposition with nine treatments: low and high N- and P-only addition (LN, HN, LP, and HP), NP coaddition (LNLP, LNHP, HNLP, and HNHP), and a control (CK). The results showed that the decomposition coefficient (k) was higher in NP coaddition treatments (P < 0.05), and lower in N- and P-only addition treatments than in CK (P < 0.05). The highest k was observed with LNLP (P < 0.05). The N- and P-only addition treatments decreased the losses of litter mass, lignin, cellulose, and condensed tannins, litter microbial biomass carbon (MBC), litter cellulase, and soil pH (P < 0.05). The NP coaddition treatments increased the losses of litter mass, lignin, and cellulose, MBC concentration, litter invertase, urease, cellulase, and catalase activities, soil arthropod diversity (S) in litterbags, and soil pH (P < 0.05). Litter acid phosphatase activity and N:P ratio were lower in N-only addition treatments but higher in P-only addition and NP coaddition treatments than in CK (P < 0.05). Structural equation model showed that litter MBC, S, cellulase, acid phosphatase, and polyphenol oxidase contributed to the loss of litter mass (P < 0.05). The litter N:P ratio was negatively logarithmically correlated with mass loss (P < 0.01). In conclusion, the negative effect of N addition on litter decomposition was reversed when P was added by increasing decomposed litter soil arthropod diversity, MBC concentration, and invertase and cellulase activities. Finally, the results highlighted the important role of the N:P ratio in litter decomposition.

Assessment of dynamic microbial community structure and rhizosphere interactions during bioaugmented phytoremediation of petroleum contaminated soil by a newly designed rhizobox system.

To understand the plant (Vigna unguiculata) and plant-growth promoting bacteria (PGPB) (Microcococcus luteus WN01) interactions in crude oil contaminated soil, experiments were conducted based on the newly designed rhizobox system. The rhizobox was divided into three main compartments namely the rhizosphere zone, the mid-zone, and the bulk soil zone, in accordance with the distance from the plant. Plants were grown in these three-chambered pots for 30 days under natural conditions. The plant root exudates were determined by analyzing for carbohydrates, amino acids, and phenolic compounds. The degradation of alkane, polycyclic aromatic hydrocarbons (PAHs), and total petroleum hydrocarbons (TPHs) were quantified by GC-FID. Soil catalase, dehydrogenase, and invertase activities were determined. The microbial community structure was assessed using denaturing gradient gel electrophoresis (DGGE). Results showed that the inoculation of M. luteus WN01 significantly enhanced cowpea root biomass and exudates, especially the phenolic compounds. Bioaugmented phytoremediation by cowpea and M. luteus promoted rhizodegradation of TPH. Cowpea stimulated microbial growth, soil dehydrogenase, and invertase activities and enhanced bacterial community diversity in oil contaminated soil. The rhizosphere zone of cowpea inoculated with M. luteus showed the highest removal efficiency, microbial activities, microbial population, and bacterial community diversity indicating the strong synergic interactions between M. luteus and cowpea.

This is the first study to characterize the rhizosphere effect of cowpea on microbial activities, population, and community structure in crude oil contaminated soil in the presence and absence of PGPB, M. luteus WN01. The rhizosphere of cowpea was found to be a degradation hotspot where microbial abundance and metabolic activities were most active. Cowpea-M. luteus association can be a good candidate that can be implemented in real field sites.

Production, immobilization and application of invertase from new wild strain Cunninghamella echinulata PA3S12MM.

AIMS: The objective of this study was to determine the best conditions to produce invertase by Cunninghamella echinulata PA3S12MM and to immobilize and apply the enzyme. METHODS AND RESULTS: The maximum production was verified in 8 days of cultivation at 28°C supplemented with 10 g L-1 apple peel, reaching 1054.85 U ml-1 . The invertase was purified from the DEAE-Sephadex column. The derivative immobilized in alginate-gelatin-calcium phosphate showed reusability >50% for 19 cycles. The derivative immobilized in glutaraldehyde-chitosan showed greater thermostability and at a different pH. The hydrolysis of 15 ml of sucrose 500 g L-1 in a fixed bed reactor (total volume of 31 ml) produced 24.44 µmol min-1 of glucose and fructose at a residence time of 30 min and a conversion factor of 0.5. CONCLUSIONS: The new wild strain C. echinulata PA3S12MM presents high invertase production in medium supplemented with an agro-industrial residue and the immobilized enzyme showed high thermal stability and resistance at a different pH. SIGNIFICANCE AND IMPACT OF THE STUDY: The fungus C. echinulata PA3S12MM is an excellent producer of invertases in Vogel medium supplemented with apple peel. The enzyme is promising for industrial application since it has good performance in reusability and inverted sugar production.

Effects of exogenous sucrose and selenium on plant growth, quality, and sugar metabolism of pea sprouts.

BACKGROUND: Pea sprouts are considered a healthy food. Sucrose is a key nutritional factor affecting taste and flavor. Meanwhile, selenium (Se) is an essential micronutrient that plays multiple roles in wide variety of physiological processes and improves crop quality and nutritional value. Nonetheless, the effects of the combination of sucrose and Se treatment on growth, quality, and sugar metabolism of pea sprouts have not been explored. RESULTS: The results revealed that sucrose at 10 mg L-1 obviously increased fresh weight, vitamin C, soluble protein, soluble sugar, fructose, glucose, and sucrose contents. Se treatments also improved nutritional quality, but higher Se (2.5 mg L-1 ) significantly inhibited the growth of seedlings. Interestingly, the combined application of sucrose (10 mg L-1 ) and Se (1.25 mg L-1 ) could effectively promote vitamin C, sucrose, and fructose contents, especially the Se content, compared with Se application alone. Additionally, there were significant differences in the regulation of sugar metabolism between Se alone and combined application of sucrose and Se. Acid invertase and neutral invertase play a pivotal role in the accumulation of soluble sugar under Se treatments alone, and acid invertase might be the key enzyme to limit sugar accumulation under combined application of sucrose and Se. CONCLUSION: The moderate combined application of sucrose (10 mg L-1 ) and Se (1.25 mg L-1 ) more effectively regulated sugar metabolism and improved nutritional quality than Se application alone did. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of Short-Term Cold Treatment on Carbohydrate Metabolism in Potato Leaves.

Plants are often challenged by an array of unfavorable environmental conditions. During cold exposure, many changes occur that include, for example, the stabilization of cell membranes, alterations in gene expression and enzyme activities, as well as the accumulation of metabolites. In the presented study, the carbohydrate metabolism was analyzed in the very early response of plants to a low temperature (2 °C) in the leaves of 5-week-old potato plants of the Russet Burbank cultivar during the first 12 h of cold treatment (2 h dark and 10 h light). First, some plant stress indicators were examined and it was shown that short-term cold exposure did not significantly affect the relative water content and chlorophyll content (only after 12 h), but caused an increase in malondialdehyde concentration and a decrease in the expression of NDA1, a homolog of the NADH dehydrogenase gene. In addition, it was shown that the content of transitory starch increased transiently in the very early phase of the plant response (3-6 h) to cold treatment, and then its decrease was observed after 12 h. In contrast, soluble sugars such as glucose and fructose were significantly increased only at the end of the light period, where a decrease in sucrose content was observed. The availability of the monosaccharides at constitutively high levels, regardless of the temperature, may delay the response to cold, involving amylolytic starch degradation in chloroplasts. The decrease in starch content, observed in leaves after 12 h of cold exposure, was preceded by a dramatic increase in the transcript levels of the key enzymes of starch degradation initiation, the α-glucan, water dikinase (GWD-EC 2.7.9.4) and the phosphoglucan, water dikinase (PWD-EC 2.7.9.5). The gene expression of both dikinases peaked at 9 h of cold exposure, as analyzed by real-time PCR. Moreover, enhanced activities of the acid invertase as well as of both glucan phosphorylases during exposure to a chilling temperature were observed. However, it was also noticed that during the light phase, there was a general increase in glucan phosphorylase activities for both control and cold-stressed plants irrespective of the temperature. In conclusion, a short-term cold treatment alters the carbohydrate metabolism in the leaves of potato, which leads to an increase in the content of soluble sugars.

Dietary Inulin Increases Lactiplantibacillus plantarum Strain Lp900 Persistence in Rats Depending on the Dietary-Calcium Level.

Synbiotics are food supplements that combine probiotics and prebiotics to synergistically elicit health benefits in the consumer. Lactiplantibacillus plantarum strains display high survival during transit through the mammalian gastrointestinal tract and were shown to have health-promoting properties. Growth on the fructose polysaccharide inulin is relatively uncommon in L. plantarum, and in this study we describe FosE, a plasmid-encoded ß-fructosidase of L. plantarum strain Lp900 which has inulin-hydrolyzing properties. FosE contains an LPxTG-like motif involved in sortase-dependent cell wall anchoring but is also (partially) released in the culture supernatant. In addition, we examined the effect of diet supplementation with inulin on the intestinal persistence of Lp900 in adult male Wistar rats in diets with distinct calcium levels. Inulin supplementation in high-dietary-calcium diets significantly increased the intestinal persistence of L. plantarum Lp900, whereas this effect was not observed upon inulin supplementation of the low-calcium diet. Moreover, intestinal persistence of L. plantarum Lp900 was determined when provided as a probiotic (by itself) or as a synbiotic (i.e., in an inulin suspension) in rats that were fed unsupplemented diets containing the different calcium levels, revealing that the synbiotic administration increased bacterial survival and led to higher abundance of L. plantarum Lp900 in rats, particularly in a low-calcium-diet context. Our findings demonstrate that inulin supplementation can significantly enhance the intestinal delivery of L. plantarum Lp900 but that this effect strongly depends on calcium levels in the diet.IMPORTANCE Synbiotics combine probiotics with prebiotics to synergistically elicit a health benefit in the consumer. Previous studies have shown that prebiotics can selectively stimulate the growth in the intestine of specific bacterial strains. In synbiotic supplementations the prebiotics constituent could increase the intestinal persistence and survival of accompanying probiotic strain(s) and/or modulate the endogenous host microbiota to contribute to the synergistic enhancement of the health-promoting effects of the synbiotic constituents. Our study establishes a profound effect of dietary-calcium-dependent inulin supplementation on the intestinal persistence of inulin-utilizing L. plantarum Lp900 in rats. We also show that in rats on a low-dietary-calcium regime, the survival and intestinal abundance of L. plantarum Lp900 are significantly increased by administering it as an inulin-containing synbiotic. This study demonstrates that prebiotics can enhance the intestinal delivery of specific probiotics and that the prebiotic effect is profoundly influenced by the calcium content of the diet.

CsSWEET1a and CsSWEET17 Mediate Growth and Freezing Tolerance by Promoting Sugar Transport across the Plasma Membrane.

Sugars Will Eventually be Exported Transporters (SWEETs) are important in plant biological processes. Expression levels of CsSWEET1a and CsSWEET17 are induced by cold acclimation (CA) and cold stress in Camellia sinensis. Here, we found that CsSWEET17 was alternatively spliced, and its exclusion (Ex) transcript was associated with the CA process. Both plasma membrane-localized CsSWEET1a and CsSWEET17 transport hexoses, but cytoplasm-localized CsSWEET17-Ex does not. These results indicate that alternative splicing may be involved in regulating the function of SWEET transporters in response to low temperature in plants. The extra C-terminal of CsSWEET17, which is not found in the tonoplast fructose transporter AtSWEET17, did not affect its plasma membrane localization but promoted its sugar transport activities. The overexpression (OE) of CsSWEET1a and CsSWEET17 genes resulted in an increased sugar uptake in Arabidopsis, affecting plant germination and growth. The leaf and seed sizes of the CsSWEET17-OE lines were significantly larger than those of the wild type. Moreover, the OE of CsSWEET1a and CsSWEET17 significantly reduced the relative electrolyte leakage levels under freezing stress. Compared with the wild type, the expression of AtCWINV genes was suppressed in both CsSWEET1a-OE and CsSWEET17-OE lines, indicating the alteration in sugar contents in the cell walls of the OE lines. Furthermore, the interaction between CsSWEET1a and CsSWEET17 was confirmed using yeast two-hybrid and bimolecular fluorescence complementation assays. We showed that CsSWEET1a and CsSWEET17 form homo-/heterodimers in the plasma membrane and mediate the partitioning of sugars between the cytoplasm and the apoplast, thereby regulating plant growth and freezing tolerance.

Acid invertase confers heat tolerance in rice plants by maintaining energy homoeostasis of spikelets.

Heat stress impairs both pollen germination and pollen tube elongation, resulting in pollination failure caused by energy imbalance. Invertase plays a critical role in the maintenance of energy homoeostasis; however, few studies investigated this during heat stress. Two rice cultivars with different heat tolerance, namely, TLY83 (heat tolerant) and LLY722 (heat susceptible), were subjected to heat stress. At anthesis, heat stress significantly decreased spikelet fertility, accompanied by notable reductions in pollen germination on stigma and pollen tube elongation in ovule, especially in LLY722. Acid invertase (INV), rather than sucrose synthase, contributed to sucrose metabolism, which explains the different tolerances of both cultivars. Under heat stress, larger enhancements in NAD(H), ATP, and antioxidant capacity were found in TLY83 compared with LLY722, whereas a sharp reduction in poly(ADP-ribose) polymerase (PARP) activity was found in the former compared with the latter. Importantly, exogenous INV, 3-aminobenzamide (a PARP inhibitor), sucrose, glucose, and fructose significantly increased spikelet fertility under heat stress, where INV activity was enhanced and PARP activity was inhibited. Therefore, INV can balance the energy production and consumption to provide sufficient energy for pollen germination and pollen tube growth under heat stress.

Modulation of photosynthetic parameters, sugar metabolism, polyamine and ion contents by silicon amendments in wheat (Triticum aestivum L.) seedlings exposed to arsenic.

The objective of the present investigation was to consider the effectiveness of exogenous silicate supplementation in reviving the arsenate imposed alterations on pigment content, Hill activity, photosynthetic parameters, sugar metabolism, polyamine, and ion contents in wheat (Triticum aestivum L. cv. PBW-343) seedlings. Experiments were conducted under different levels of arsenate (0, 25 µM, 50 µM, and 100 µM) in combination with silicate (0, 5 mM) in a hydroponic environment with modified Hoagland's solution for 21 days to determine the ameliorative role of silicon (Si). Arsenate exposure led to a decline in chlorophyll content by 28% and Hill activity by 30% on an average along with photosynthetic parameters. Activity of starch phosphorylase increased causing a subsequent decrease in starch contents by 26%. Degradation of starch enhanced sugar contents by 61% in the test cultivar. Dose-dependant increments in the activities of carbohydrate metabolizing enzymes viz., sucrose synthase, sucrose phosphate synthase, and acid invertase were also noted. Putrescine content was significantly enhanced along with a consequent decline in spermidine and spermine contents. The macro- and micronutrient contents declined proportionally with arsenate imposition. Conversely, silicate amendments irrespective of all arsenate concentrations brought about considerable alterations in all parameters tested with respect to arsenate treatment alone. Marked improvement in pigment content and Hill activity also improved the gas exchange parameters. Soluble sugar contents decreased and starch contents were enhanced. Increase in polyamine contents improved the ionic balance in the test cultivar as well. This study highlights the potentiality of silicon in ameliorating the ecotoxicological risks associated with arsenic pollution and the probable ability of silicon to offer an approach in mitigating arsenate-induced stress leading to restoration of growth and metabolism in wheat seedlings.

Expression analysis of Cell wall invertase under abiotic stress conditions influencing specialized metabolism in Catharanthus roseus.

Catharanthus roseus is a commercial source for anti-cancer terpenoid indole alkaloids (TIAs: vincristine and vinblastine). Inherent levels of these TIAs are very low, hence research studies need to focus on enhancing their levels in planta. Since primary metabolism provides precursors for specialized-metabolism, elevating the former can achieve higher amounts of the latter. Cell Wall Invertase (CWIN), a key enzyme in sucrose-metabolism catalyses the breakdown of sucrose into glucose and fructose, which serve as carbon-skeleton for specialized-metabolites. Understanding CWIN regulation could unravel metabolic-engineering approaches towards enhancing the levels of TIAs in planta. Our study is the first to characterize CWIN at gene-expression level in the medicinal plant, C. roseus. The CWINs and their inter-relationship with sucrose and TIA metabolism was studied at gene and metabolite levels. It was found that sucrose-supplementation to C. roseus leaves significantly elevated the monomeric TIAs (vindoline, catharanthine) and their corresponding genes. This was further confirmed in cross-species, wherein Nicotiana benthamiana leaves transiently-overexpressing CrCWIN2 showed significant upregulation of specialized-metabolism genes: NbPAL2, Nb4CL, NbCHS, NbF3H, NbANS, NbHCT and NbG10H. The specialized metabolites- cinnamic acid, coumarin, and fisetin were significantly upregulated. Thus, the present study provides a valuable insight into metabolic-engineering approaches towards augmenting the levels of therapeutic TIAs.

CsINV5, a tea vacuolar invertase gene enhances cold tolerance in transgenic Arabidopsis.

BACKGROUND: Vacuolar invertases (VINs) have been reported to regulate plant growth and development and respond to abiotic stresses such as drought and cold. With our best knowledge, the functions of VIN genes little have been reported in tea plant (Camellia sinensis L.). Therefore, it is necessary to develop research in this field. RESULTS: Here, we identified a VIN gene, CsINV5, which was induced by cold acclimation and sugar treatments in the tea plant. Histochemical assays results showed that the 1154 bp 5'-flanking sequence of CsINV5 drove ß-glucuronidase (GUS) gene expression in roots, stems, leaves, flowers and siliques of transgenic Arabidopsis during different developmental stages. Moreover, promoter deletion analysis results revealed that an LTRE-related motif (CCGAAA) and a WBOXHVISO1 motif (TGACT) within the promoter region of CsINV5 were the core cis-elements in response to low temperature and sugar signaling, respectively. In addition, overexpression of CsINV5 in Arabidopsis promoted taproot and lateral root elongation through glucose-mediated effects on auxin signaling. Based on physiological and RNA-seq analysis, we found that overexpression of CsINV5 improved cold tolerance in transgenic Arabidopsis mainly by increasing the contents of glucose and fructose, the corresponding ratio of hexose to sucrose, and the transcription of osmotic-stress-related genes (P5CS1, P5CS2, AtLEA3, COR413-PM1 and COR15B) to adjust its osmotic potential. CONCLUSIONS: Comprehensive experimental results suggest that overexpression of CsINV5 may enhance the cold tolerance of plant through the modification of cellular sugar compounds contents and osmotic regulation related pathways.

Effects of clay combined with moisture management on Cd immobilization and fertility index of polluted rice field.

A field-scale trial was conducted to investigate the remediation effects of sepiolite on Cd-polluted paddy soils under different moisture managements, using a series of variables (pH and extractable Cd of soil, plant Cd concentration, plant nutrition and enzyme activity in soil). Results revealed that soil pH increased significantly after sepiolite addition, which promoted the reduction in extractable Cd in soil. After applying 0.5-2.5% sepiolite into soil, due to higher pH and lower TCLP Cd concentration, brown rice Cd reduced by 17-67% under continuous flooding, 14-62% under conventional irrigation, and 13-61% under wetting irrigation (p < 0.05). The activities of phosphatase and invertase increased compared with unamended soil (p < 0.05). The available phosphorus in clay treated soil showed a remarkable raise, with a maximum increase by 14.5%, 16.9% and 18.1% under three moisture managements (p < 0.05). The increasing values of enzyme activity and then plant nutrition in soil revealed that clay application improved the ecological condition of Cd-contaminated paddy soil. The sepiolite application in combination with continuous flooding provided an efficient and safe remediation technology for Cd-polluted rice field.

Rapid sucrose monitoring in green coffee samples using multienzymatic biosensor.

Amperometric biosensor utilizing FAD-dependent glucose dehydrogenase (FAD-GDH) for a specific sucrose monitoring in green coffee is described. FAD-GDH was co-immobilized with invertase and mutarotase on a thin-layer gold planar electrode using chitosan. The biosensor showed a wide linearity (from 10 to 1200 µM), low detection limit (8.4 µM), fast response time (50 s), and appeared to be O2 independent. In addition the biosensors exhibited a good operational (3 days) and storage (1 year) stability. Finally, the results achieved from the biosensor measurements of sucrose in 17 samples of green coffee (Coffea arabica, C. canephora and C. liberica) were compared with those obtained by the standard HPLC method. The good correlation among results of real samples, satisfactory analytical performance and simple use of the presented biosensor make it suitable for application in coffee industry.

Suppression of the vacuolar invertase gene delays senescent sweetening in chipping potatoes.

BACKGROUND: Potato chip processors require potato tubers that meet quality specifications for fried chip color, and color depends largely upon tuber sugar contents. At later times in storage, potatoes accumulate sucrose, glucose, and fructose. This developmental process, senescent sweetening, manifests as a blush of color near the center of the fried chip, becomes more severe with time, and limits the storage period. Vacuolar invertase (VInv) converts sucrose to glucose and fructose and is hypothesized to play a role in senescent sweetening. To test this hypothesis, senescent sweetening was quantified in multiple lines of potato with reduced VInv expression. RESULTS: Chip darkening from senescent sweetening was delayed by about 4 weeks for tubers with reduced VInv expression. A strong positive correlation between frequency of dark chips and tuber hexose content was observed. Tubers with reduced VInv expression had lower hexose to sucrose ratios than controls. CONCLUSION: VInv activity contributes to reducing sugar accumulation during senescent sweetening. Sucrose breakdown during frying may contribute to chip darkening. Suppressing VInv expression increases the storage period of the chipping potato crop, which is an important consideration, as potatoes with reduced VInv expression are entering commercial production in the USA. © 2017 Society of Chemical Industry.