Monosaccharide Transport Research Articles

Comparative transcriptome analysis of Aspergillus niger revealed its biocontrol mechanisms in response to the guava wilt pathogen Fusarium oxysporum f. sp. psidii.

Wilt is one of the major destructive diseases in guava cultivation worldwide. Biocontrol agent Aspergillus niger has been recognized for its efficacy against various plant pathogens including guava wilt disease. This biocontrol fungus has been widely studied for its mycoparasitic and antibiosis mechanisms. Still, a notable gap exists in the literature regarding the molecular mechanisms and biosynthetic pathways underlying biocontrol activity when challenged with guava wilt pathogen. In this investigation, we conducted comprehensive global RNA sequencing, which generated a total of 35.16 GB data, comprising 18–22 million reads having 52-54% GC content. Over 55,464 transcripts displayed differential expression profiles during the interaction of biocontrol and the pathogen, out of that 5,285 transcripts were expressed at FC2 and Pval 0.05. They were mainly associated with catalytic activity (48.45%), protein or DNA binding activity (44.9%), transporter activity (8.2%), and transcription regulator activity (5.5%). In the biological process category, 36.5% and 34.7% of transcripts were linked to "metabolic" and "cellular processes," respectively. The upregulated DEGs were predominantly linked to hydrolytic activity and secondary metabolite production, encompassing AB hydrolases, cyanate hydratase, Isochorismatase hydrolase, galacturan 1,4-alpha-galacturonidase B, Esterase/Lipase, MFS monosaccharide transporter, ATP-binding cassette transporter, polyamine transporter 3, endoglucanase A, and non-ribosomal siderophore peptide synthase (SidC). Our investigation highlighted that the biocontrol mechanism primarily involves the active participation of hydrolytic enzymes, transporters, transcription factors, and secondary metabolites. Additionally, the data were validated using RT-qPCR, affirming the consistency of RNA-seq findings. This study represents the inaugural effort to elucidate the biocontrol mechanism of A. niger against F. oxysporum f. sp. psidii using the RNA-seq approach. The findings shed light on the antagonistic mechanisms of A. niger at the molecular level, enhancing our comprehension of A. niger as a biocontrol agent and deepening our exploration of biocontrol and pathogen interactions.

Regulation of gene expression in milk secretory pathways during secretory activation in Holstein cows

Increased transcription of genes involved in lactose synthesis is a key feature of secretory activation of the mammary gland. We determined which genes are transcriptionally regulated during the transition from colostrum to milk in cows and whether more frequent milking of one udder half would increase milk yields and alter gene expression. We enrolled 12 Holstein cows immediately after calving, harvested colostrum, then randomly assigned one udder half to 12 h (2X) or 6 h (4X) milking intervals for 48 h after first milking. After 48 h, all quarters were milked twice daily until d7, when final quarter milk yields were collected. Yields and composition of colostrum and milk were recorded for each 12 h interval. After each milking, a strip sample of hind milk was collected for isolation of RNA from milk fat and quantification of selected transcripts via qPCR. Milk, milk fat, total protein, and lactose yields increased significantly over the initial 48 h and at d7 after calving. Quarters on 4X treatment produced more milk than the contralateral 2X quarters. Genes upregulated concomitantly with milk yields encoded α-lactalbumin (LALBA), β-1,4-galactosyltransferase (B4GALT1), fatty acid synthase (FASN), β casein (CSN2), and folate receptor α (FOLR1). Downregulated genes encoded monosaccharide transporters (SLC2A3, SLC2A8, SLC35A2) and enzymes involved in galactose synthesis (HK1, PGM1, GALE). Three genes were initially downregulated but later upregulated at d7 (LPIN1, SLC2A1, UGP2). Notably, milking frequency had no effect on gene expression. Sequential upregulation first of genes encoding the former enzymes, then of UGP2, may be necessary for copious milk production. However, the local effects of milking frequency on milk production during lactogenesis do not appear to be controlled by transcription of these genes related to lactose synthesis.

Genome-wide identification and investigation of monosaccharide transporter gene family based on their evolution and expression analysis under abiotic stress and hormone treatments in maize (Zea mays L.)

BackgroundMonosaccharide transporter (MST) family, as a carrier for monosaccharide transport, plays an important role in carbon partitioning and widely involves in plant growth and development, stress response, and signaling transduction. However, little information on the MST family genes is reported in maize (Zea mays), especially in response to abiotic stresses. In this study, the genome-wide identification of MST family genes was performed in maize.ResultA total of sixty-six putative members of MST gene family were identified and divided into seven subfamilies (including SPT, PMT, VGT, INT, pGlcT, TMT, and ERD) using bioinformatics approaches, and gene information, phylogenetic tree, chromosomal location, gene structure, motif composition, and cis-acting elements were investigated. Eight tandem and twelve segmental duplication events were identified, which played an important role in the expansion of the ZmMST family. Synteny analysis revealed the evolutionary features of MST genes in three gramineous crop species. The expression analysis indicated that most of the PMT, VGT, and ERD subfamilies members responded to osmotic and cadmium stresses, and some of them were regulated by ABA signaling, while only a few members of other subfamilies responded to stresses. In addition, only five genes were induced by NaCl stress in MST family.ConclusionThese results serve to understand the evolutionary relationships of the ZmMST family genes and supply some insight into the processes of monosaccharide transport and carbon partitioning on the balance between plant growth and development and stress response in maize.

Long-term intermittent fasting induces sex-dependent changes in small intestine from SAMP8 aged mice

Background: Intermittent fasting (IF) is a popular and effective method to decrease body weight. Yet, the effects of IF on aged intestine is unknown. SAMP8 (Senescence Accelerated Mouse-Prone 8) mice are used as a model for studying aging. This study aimed to examine the potential for IF to ameliorate age-associated disturbances in murine jejunum. Methods: Two-month-old male and female SAMP8 mice were randomly assigned to either an IF protocol or an ad-libitum diet (AL) for the 8-month study (n=7-10 group). Fasted mice followed a 24-hour alternate day fasting protocol. At the end of the study mice were euthanized and jejunum stored at −80°C until use for western blot or other assay, and a segment was fixed for histology. Results: IF resulted in significantly less weight gain in both males (22% less, n=7-10, p<0.05) and females (33% less, n=7-8, p<0.05) and response to glucose load (glucose tolerance testing) was comparable in both sexes: area under curve for AL > IF. Interestingly, IF significantly reduced fasting serum glucose levels in males (30% less, n=6, p<0.05), but IF had no effect on fasting serum glucose in females. In jejunum, we assessed: protein expression, health, and morphology. In females, IF led to a 57% decrease in GLUT2 expression (n=5-6, p<0.05) versus AL. GLUT2 moves glucose/galactose and fructose out of the enterocyte into the blood, suggesting restructuring of monosaccharide transport due to IF. IF had no effect on jejunum GLUT5 or SGLT1 expression. Cleaved Caspase-3 expression was decreased by IF in both sexes versus AL. This reduction was greater in females, suggesting a sex-dependent protective role of IF against apoptosis. Moreover, IF induced a significant increase 1.4-fold (n=5=6, p<0.05) in jejunum superoxide dismutase (SOD) activity in both sexes. Jejunum morphology was significantly changed in females only: IF induced both a decrease in villi length (by 21%, n=4/group, p<0.05) and a decrease in wall thickness (by 7%, n=4/group, p<0.05). Conclusions: In both sexes, IF decreased body weight, yet in females resting glucose levels were unchanged by IF. In females, IF reduced monosaccharide absorption out of intestines, yet improved overall intestinal health, increasing antioxidant levels with SOD. These findings collectively highlight the complex effects of IF on cellular processes and demonstrate significant sex-dependent aged intestinal responses. Unraveling the underlying molecular mechanisms driving these sex-dependent IF-induced effects is currently under evaluation. Midwestern-Arizona Alzheimer’s Consortium Grant, Midwestern University Intramural Grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Transcriptomic and biochemical analysis of the mechanism of sodium gluconate promoting the degradation of benzo [a] pyrene by Bacillus subtilis MSC4

Benzo[a]pyrene (B[a]P) is a carcinogenic environmental pollutant widely present in the environment and can enter the human body through the food chain. It is therefore essential to treat and remediate the B[a]P-contaminated environment. Microbial remediation of B[a]P-contaminated environments is considered to be one of the most effective strategies, and the addition of biostimulants is a feasible method to further improve the effectiveness of microbial remediation. In this study, we used Bacillus subtilis MSC4 to screen for the stimulation of sodium gluconate, which promoted B[a]P degradation. Based on biochemical and transcriptomic analyses, Sodium gluconate was found to significantly increase the biomass of MSC4 and the expression of most genes involved in B[a]P degradation. Activities of central carbon metabolism, fatty acid β-oxidation and oxidative phosphorylation were all promoted. The significant increase in acid-induced oxalate decarboxylase expression indicates a decrease in intracellular pH, which promoted the synthesis of acetoin and lactate. Genes involved in the nitrogen cycle, especially nitrification and denitrification, were significantly up-regulated, contributing to B[a]P degradation. Genes involved in the synthesis of enzyme cofactors, including thiamine, molybdenum cofactors, NAD and heme, were up-regulated, which contributes to increasing enzyme activity in metabolic pathways. Up-regulation of genes in flagella assembly, chemotaxis, and lipopeptide synthesis is beneficial for the dissolution and uptake of B[a]P. Genes related to the sugar transport system were upregulated, which facilitates the transport and absorption of monosaccharides and oligosaccharides by MSC4. This study provides a theoretical basis for the further application of sodium gluconate in the treatment of PAH-contaminated sites.

Phaseolus vulgaris STP13.1 is an H+-coupled monosaccharide transporter, present in source leaves and seed coats, with higher substrate affinity at depolarized potentials.

Sugar transport proteins (STPs) are high-affinity H+-coupled hexose symporters. Recently, the contribution of STP13 to bacterial and fungal pathogen resistance across multiple plant species has garnered significant interest. Quantitative PCR analysis of source leaves, developing embryos, and seed coats of Phaseolus vulgaris L. (common bean) revealed that PvSTP13.1 was expressed in source leaves and seed coats throughout seed development. In contrast, PvSTP13.1 transcripts were detected at exceedingly low levels in developing embryos. To characterize the transport mechanism, PvSTP13.1 was expressed in Xenopus laevis oocytes, and inward-directed currents were analyzed using two-electrode voltage clamping. PvSTP13.1 was shown to function as an H+-coupled monosaccharide symporter exhibiting a unique high affinity for hexoses and aldopentoses at depolarized membrane potentials. Specifically, of the 31 assessed substrates, which included aldohexoses, deoxyhexoses, fructose, 3-O-methyl-D-glucose, aldopentoses, polyols, glycosides, disaccharides, trisaccharides, and glucuronic acid, PvSTP13.1 displayed the highest affinity (K 0.5) for glucose (43 μM), mannose (92 μM), galactose (145 μM), fructose (224 μM), xylose (1.0mM), and fucose (3.7mM) at pH5.6 at a depolarized membrane potential of -40 mV. The results presented here suggest PvSTP13.1 contributes to retrieval of hexoses from the apoplasmic space in source leaves and coats of developing seeds.

Identification and Expression Analysis of Putative Sugar Transporter Gene Family during Bulb Formation in Lilies.

Sugar transporters play important roles in plant growth and development, flowering and fruiting, as well as responses to adverse abiotic and biotic environmental conditions. Lilies (Lilium spp.) are some of the most representative ornamental bulbous flowers. Sugar metabolism is critical for bulb formation in lilies; therefore, clarifying the amount and expression pattern of sugar transporters is essential for further analyzing their roles in bulb formation. In this study, based on the transcriptome data of the Lilium Oriental hybrid 'Sorbonne' and Lilium × formolongi, a total of 69 and 41 sugar transporters were identified in 'Sorbonne' and Lilium × formolongi, respectively, by performing bioinformatics analysis. Through phylogenetic analysis, monosaccharide transporters (MSTs) can be divided into seven subfamilies, sucrose transporters (SUTs) can be divided into three subgroups, and sugars will eventually be exported transporters (SWEETs) can be divided into four clades. According to an analysis of conserved motifs, 20, 14, and 12 conserved motifs were predicted in MSTs, SUTs, and SWEETs, respectively. A conserved domain analysis showed that MSTs and SUTs contained a single domain, whereas most of the SWEETs harbored two MtN3/saliva domains, also known as a PQ-loop repeat. The LohINT1, which was predicted to have a smaller number of transmembrane structural domains, was cloned and analyzed for subcellular localization. It was found that the LohINT1 protein is mainly localized in the cell membrane. In addition, the expression analysis indicated that 22 LohMSTs, 1 LohSUTs, and 5 LohSWEETs were upregulated in 'Sorbonne' 1 day after scale detachment treatment, suggesting that they may regulate the initiation of the bulblet. A total of 10 LflMSTs, 1 LflSUTs, and 6 LflSWEETs were upregulated 4~6 months after sowing, which corresponds to the juvenile-to-adult transition phase of Lilium × formolongi, suggesting that they may also play a role in the accompanying bulb swelling process. Combined with quantitative real-time PCR (qRT-PCR) analysis, LohSTP8 and LohSTP12 were significantly overexpressed during the extremely early stage of bulblet initiation, and LflERD6.3 was significantly overexpressed during the growth of the underground bulblet, suggesting that they may be key sugar transporters in the formation of lily bulbs, which needs further functional verification.

Monosaccharide transporter OsMST6 is activated by transcription factor OsERF120 to enhance chilling tolerance in rice seedlings.

Chilling stress caused by extreme weather is threatening global rice (Oryza sativa L.) production. Identifying components of the signal transduction pathways underlying chilling tolerance in rice would advance molecular breeding. Here, we report that OsMST6, which encodes a monosaccharide transporter, positively regulates the chilling tolerance of rice seedlings. mst6 mutants showed hypersensitivity to chilling, while OsMST6 overexpression lines were tolerant. During chilling stress, OsMST6 transported more glucose into cells to modulate sugar and abscisic acid signaling pathways. We showed that the transcription factor OsERF120 could bind to the DRE/CRT element of the OsMST6 promoter and activate the expression of OsMST6 to positively regulate chilling tolerance. Genetically, OsERF120 was functionally dependent on OsMST6 when promoting chilling tolerance. In summary, OsERF120 and OsMST6 form a new downstream chilling regulatory pathway in rice in response to chilling stress, providing valuable findings for molecular breeding aimed at achieving global food security.

Utilization of plant-derived sugars and lipids are coupled during colonization of rhizoplane and rhizosphere by the fungus Metarhizium robertsii

Plant-derived sugars and lipids are key nutritional sources for plant associated fungi. However, the relationship between utilization of host-derived sugars and lipids during development of the symbiotic association remains unknown. Here we show that the fungus Metarhizium robertsii also needs plant-derived lipids to develop symbiotic relationship with plants. The fatty acid binding proteins FABP1 and FABP2 are important for utilization of plant-derived lipids as the deletion of Fabp1 and Fabp2 significantly reduced the ability of M. robertsii to colonize rhizoplane and rhizosphere of maize and Arabidopsis thaliana. Deleting Fabp1 and Fabp2 increased sugar utilization by upregulating six sugar transporters, and this explains why deleting the monosaccharide transporter gene Mst1, which plays an important role in utilization of plant-derived sugars, had no impact on the ability of the double-gene deletion mutant ΔFabp1::ΔFabp2 to colonize plant roots. FABP1 and FABP2 were also found in other plant-associated Metarhizium species, and they were highly expressed in the medium using the tomato root exudate as the sole carbon and nitrogen source, suggesting that they could be also important for these species to develop symbiotic relationship with plants. In conclusion, we discovered that utilization of plant-derived sugars and lipids are coupled during colonization of rhizoplane and rhizosphere by M. robertsii.

Genome-Wide Association Study of Cooked Rice Textural Attributes and Starch Physicochemical Properties in indica Rice

Rice cooking and eating qualities (CEQ) are mainly determined by cooked rice textural parameters and starch physicochemical properties. However, the genetic bases of grain texture and starch properties in rice have not been fully understood. We conducted a genome-wide association study for apparent amylose content (AAC), starch pasting viscosities, and cooked rice textural parameters using 279 indica rice accessions from the 3 000 Rice Genome Project. We identified 26 QTLs in the whole population and detected single nucleotide polymorphisms (SNPs) with the lowest P-value at the Waxy (Wx) locus for all traits except pasting temperature and cohesiveness. Additionally, we detected significant SNPs at the SUBSTANDARD STARCH GRAIN6 (SSG6) locus for AAC, setback (SB), hardness, adhesiveness, chewiness (CHEW), gumminess (GUM), and resilience. We subsequently divided the population using a SNP adjacent to the Waxy locus, and identified 23 QTLs and 12 QTLs in two sub-panels, WxT and WxA, respectively. In these sub-panels, SSG6 was also identified to be associated with pasting parameters, including peak viscosity, hot paste viscosity, cold paste viscosity, and consistency viscosity. Furthermore, a candidate gene encoding monosaccharide transporter 5 (OsMST5) was identified to be associated with AAC, breakdown, SB, CHEW, and GUM. In total, 39 QTLs were co-localized with known genes or previously reported QTLs. These identified genes and QTLs provide valuable information for genetic manipulation to improve rice CEQ.

Substrate selectivity and unique sequence signatures in SWEET/semiSWEET homologs of four taxonomic groups: Sequence analysis and phylogenetic studies.

The recently discovered SWEET (Sugar Will Eventually be Exported Transporter) proteins are involved in the selective transport of monosaccharides and disaccharides. The prokaryotic counterparts, semiSWEETs, form dimers with each monomer forming a triple-helix transmembrane bundle (THB). The longer eukaryotic SWEETs have seven transmembrane helices with two THBs and a linker helix. Structures of semiSWEETs/SWEETs have been determined experimentally. Experimental studies revealed the role of plant SWEETs in vital physiological processes and identified residues responsible for substrate selectivity. However, SWEETs/semiSWEETs from metazoans and bacteria are not characterized. In this study, we used structure-based sequence alignment and compared more than 2000 SWEET/semiSWEETs from four different taxonomic groups. Conservation of residue/chemical property was examined at all positions. Properties of clades/subclades of phylogenetic trees from each taxonomic group were analyzed. Conservation pattern of known residues in the selectivity-filter was used to predict the substrate preference of plant SWEETs and some clusters of metazoans and bacteria. Some residues at the gating and substrate-binding regions, pore-facing positions and at the helix-helix interface are conserved across all taxonomic groups. Conservation of polar/charged residues at specific pore-facing positions, helix-helix interface and in loops seems to be unique for plant SWEETs. Overall, the number of conserved residues is less in metazoan SWEETs. Plant and metazoan SWEETs exhibit high conservation of four and three proline residues respectively in "proline tetrad." Further experimental studies can validate the predicted substrate selectivity and significance of conserved polar/charged/aromatic residues at structurally and functionally important positions of SWEETs/semiSWEETs in plants, metazoans and bacteria.

Vacuolar Sugar Transporter TMT2 Plays Crucial Roles in Germination and Seedling Development in Arabidopsis

Vacuolar sugar transporters transport sugar across the tonoplast, are major players in maintaining sugar homeostasis, and therefore play vital roles in plant growth, development, and biomass yield. In this study, we analyzed the physiological roles of the tonoplast monosaccharide transporter 2 (TMT2) in Arabidopsis. In contrast to the wild type (WT) that produced uniform seedlings, the tmt2 mutant produced three types of offspring: un-germinated seeds (UnG), seedlings that cannot form true leaves (tmt2-S), and seedlings that develop normally (tmt2-L). Sucrose, glucose, and fructose can substantially, but not completely, rescue the abnormal phenotypes of the tmt2 mutant. Abnormal cotyledon development, arrested true leaf development, and abnormal development of shoot apical meristem (SAM) were observed in tmt2-S seedlings. Cotyledons from the WT and tmt2-L seedlings restored the growth of tmt2-S seedlings through micrografting. Moreover, exogenous sugar sustained normal growth of tmt2-S seedlings with cotyledon removed. Finally, we found that the TMT2 deficiency resulted in growth defects, most likely via changing auxin signaling, target of rapamycin (TOR) pathways, and cellular nutrients. This study unveiled the essential functions of TMT2 for seed germination and initial seedling development, ensuring cotyledon function and mobilizing sugars from cotyledons to seedlings. It also expanded the current knowledge on sugar metabolism and signaling. These findings have fundamental implications for enhancing plant biomass production or seed yield in future agriculture.

Molecular physiology for the increase of soluble sugar accumulation in citrus fruits under drought stress

To investigate the mechanism for drought promoting soluble sugar accumulation will be conducive to the enhancement of citrus fruit quality as well as stress tolerance. Fruit sucrose mainly derives from source leaves. Its accumulation in citrus fruit cell vacuole involves in two processes of unloading in the fruit segment membrane (SM) and translocating to the vacuole of fruit juice sacs (JS). Here, transcript levels of 47 sugar metabolism- and transport-related genes were compared in fruit SM or JS between drought and control treatments. Results indicated that transcript levels of cell wall invertase genes (CwINV2/6) and sucrose synthase genes (SUS2/6) in the SM were significantly increased by the drought. Moreover, transcript levels of SWEET genes (CsSWEET1/2/4/5/9) and monosaccharide transporter gene (CsPMT3) were significantly increased in SM under drought treatment. On the other hand, SUS1/3 and vacuolar invertase (VINV) transcript levels were significantly increased in JS by drought; CsPMT4, sucrose transporter gene 2 (CsSUT2), tonoplast monosaccharide transporter gene 2 (CsTMT2), sugar transport protein gene 1 (CsSTP1), two citrus type I V-PPase genes (CsVPP1, and CsVPP2) were also significantly increased in drought treated JS. Collectively, the imposition of drought stress resulted in more soluble sugar accumulation through enhancing sucrose download by enhancing sink strength- and transport ability-related genes, such as CwINV2/6, SUS2/6, CsSWEET1/2/4/5/9, and CsPMT3, in fruit SM, and soluble sugar storage ability by increasing transcript levels of genes, such as CsPMT4, VINV, CsSUT2, CsTMT2, CsSTP1, CsVPP1, and CsVPP2, in fruit JS.

Comparative Study of Bolting Adaptability between 60Co-Induced Rape and Its Original Material

In southern China, the fresh shoots of rape are used as a high-quality seasonal vegetable owing to their pleasant taste. In this study, we investigated the taste and quality of fresh shoots of Fanmingyoutai, which was derived from WH23 by 60Co mutation. WH23 was used as a control (CK). Physiological indexes, transcriptome analyses, and metabolomics analyses between Fanmingyoutai and CK were studied and the related key differential genes were identified. The results showed that the glucosinolate content of Fanmingyoutai seeds was 51.14% lower than that of CK, and the contents of soluble sugar and vitamin C in the fresh shoots of Fanmingyoutai were 2.1 times and 1.4 times higher, respectively, than CK. Using transcriptome analyses, we identified that the differential genes were involved in glycan biosynthesis and metabolism, energy metabolism, carbohydrate metabolism, and the metabolism of cofactors and vitamins. Metabolomics analyses demonstrated that the contents of sucrose and D-fructose in the fresh shoots of Fanmingyoutai were 1.22 times and 1.15 times higher, respectively, than those in CK. Using qRT-PCR analyses, the expression of SWEET17, STP5, and GSL in the fresh shoots and leaves of Fanmingyoutai was two times higher than that in CK. SWEET17 (involved in sugar production and transport), STP5 (involved in monosaccharide transport), and GSL (involved in glucosinolate accumulation) may be the key functional genes. We concluded that the low glucosinolate content and high sucrose and D-fructose contents may be the main factors affecting the taste of fresh shoots of Fanmingyoutai and CK; SWEET17, STP5, and GSL may be the key related genes. This research provides a reference for the breeding and molecular mechanisms of new edible rape varieties.

Starving the enemy: how plant and microbe compete for sugar on the border.

As the primary energy source for a plant host and microbe to sustain life, sugar is generally exported by Sugars Will Eventually be Exported Transporters (SWEETs) to the host extracellular spaces or the apoplast. There, the host and microbes compete for hexose, sucrose, and other important nutrients. The host and microbial monosaccharide transporters (MSTs) and sucrose transporters (SUTs) play a key role in the "evolutionary arms race". The result of this competition hinges on the proportion of sugar distribution between the host and microbes. In some plants (such as Arabidopsis, corn, and rice) and their interacting pathogens, the key transporters responsible for sugar competition have been identified. However, the regulatory mechanisms of sugar transporters, especially in the microbes require further investigation. Here, the key transporters that are responsible for the sugar competition in the host and pathogen have been identified and the regulatory mechanisms of the sugar transport have been briefly analyzed. These data are of great significance to the increase of the sugar distribution in plants for improvement in the yield.

Vacuolar sugar transporter EARLY RESPONSE TO DEHYDRATION 6-LIKE4 affects fructose signaling and plant growth.

Regulation of intracellular sugar homeostasis is maintained by regulation of activities of sugar import and export proteins residing at the tonoplast. We show here that the EARLY RESPONSE TO DEHYDRATION6-LIKE4 (ERDL4) protein, a member of the monosaccharide transporter family, resides in the vacuolar membrane in Arabidopsis (Arabidopsis thaliana). Gene expression and subcellular fractionation studies indicated that ERDL4 participates in fructose allocation across the tonoplast. Overexpression of ERDL4 increased total sugar levels in leaves due to a concomitantly induced stimulation of TONOPLAST SUGAR TRANSPORTER 2 (TST2) expression, coding for the major vacuolar sugar loader. This conclusion is supported by the finding that tst1-2 knockout lines overexpressing ERDL4 lack increased cellular sugar levels. ERDL4 activity contributing to the coordination of cellular sugar homeostasis is also indicated by two further observations. Firstly, ERDL4 and TST genes exhibit an opposite regulation during a diurnal rhythm, and secondly, the ERDL4 gene is markedly expressed during cold acclimation, representing a situation in which TST activity needs to be upregulated. Moreover, ERDL4-overexpressing plants show larger rosettes and roots, a delayed flowering time, and increased total seed yield. Consistently, erdl4 knockout plants show impaired cold acclimation and freezing tolerance along with reduced plant biomass. In summary, we show that modification of cytosolic fructose levels influences plant organ development and stress tolerance.

Exploring the Core Bacteria and Functional Traits in Pecan (Carya illinoinensis) Rhizosphere.

Pecan (Carya illinoinensis) and Chinese hickory (Carya cathayensis) are important commercially cultivated nut trees. They are phylogenetically closely related plants; however, they exhibit significantly different phenotypes in response to abiotic stress and development. The rhizosphere selects core microorganisms from bulk soil, playing a pivotal role in the plant's resistance to abiotic stress and growth. In this study, we used metagenomic sequencing to compare the selection capabilities of seedling pecan and seedling hickory at taxonomic and functional levels in bulk soil and the rhizosphere. We observed that pecan has a stronger capacity to enrich rhizosphere plant-beneficial microbe bacteria (e.g., Rhizobium, Novosphingobium, Variovorax, Sphingobium, and Sphingomonas) and their associated functional traits than hickory. We also noted that the ABC transporters (e.g., monosaccharide transporter) and bacterial secretion systems (e.g., type IV secretion system) are the core functional traits of pecan rhizosphere bacteria. Rhizobium and Novosphingobium are the main contributors to the core functional traits. These results suggest that monosaccharides may help Rhizobium to efficiently enrich this niche. Novosphingobium may use a type IV secretion system to interact with other bacteria and thereby influence the assembly of pecan rhizosphere microbiomes. Our data provide valuable information to guide core microbial isolation and expand our knowledge of the assembly mechanisms of plant rhizosphere microbes. IMPORTANCE The rhizosphere microbiome has been identified as a fundamental factor in maintaining plant health, helping plants to fight the deleterious effects of diseases and abiotic stresses. However, to date, studies on the nut tree microbiome have been scarce. Here, we observed a significant "rhizosphere effect" on the seedling pecan. We furthermore demonstrated the core rhizosphere microbiome and function in the seedling pecan. Moreover, we deduced possible factors that help the core bacteria, such as Rhizobium, to efficiently enrich the pecan rhizosphere and the importance of the type IV system for the assembly of pecan rhizosphere bacterial communities. Our findings provide information for understanding the mechanism of the rhizosphere microbial community enrichment process.

Genome-Wide Identification and an Evolution Analysis of Tonoplast Monosaccharide Transporter (TMT) Genes in Seven Gramineae Crops and Their Expression Profiling in Rice.

The tonoplast monosaccharide transporter (TMT) family plays essential roles in sugar transport and plant growth. However, there is limited knowledge about the evolutionary dynamics of this important gene family in important Gramineae crops and putative function of rice TMT genes under external stresses. Here, the gene structural characteristics, chromosomal location, evolutionary relationship, and expression patterns of TMT genes were analyzed at a genome-wide scale. We identified six, three, six, six, four, six, and four TMT genes, respectively, in Brachypodium distachyon (Bd), Hordeum vulgare (Hv), Oryza rufipogon (Or), Oryza sativa ssp. japonica (Os), Sorghum bicolor (Sb), Setaria italica (Si), and Zea mays (Zm). All TMT proteins were divided into three clades based on the phylogenetic tree, gene structures, and protein motifs. The transcriptome data and qRT-PCR experiments suggested that each clade members had different expression patterns in various tissues and multiple reproductive tissues. In addition, the microarray datasets of rice indicated that different rice subspecies responded differently to the same intensity of salt or heat stress. The Fst value results indicated that the TMT gene family in rice was under different selection pressures in the process of rice subspecies differentiation and later selection breeding. Our findings pave the way for further insights into the evolutionary patterns of the TMT gene family in the important Gramineae crops and provide important references for characterizing the functions of rice TMT genes.

The novel chloroplast glucose transporter pGlcT2 affects adaptation to extended light periods

Intracellular sugar compartmentation is critical in plant development and acclimation to challenging environmental conditions. Sugar transport proteins are present in plasma membranes and in membranes of organelles such as vacuoles, the Golgi apparatus, and plastids. However, there may exist other transport proteins with uncharacterized roles in sugar compartmentation. Here we report one such, a novel transporter of the Monosaccharide Transporter Family (MSF), the closest phylogenetic homolog of which is the chloroplast-localized glucose transporter pGlcT and that we therefore term plastidic glucose transporter 2 (pGlcT2). We show, using gene-complemented glucose uptake deficiency of an Escherichia coli ptsG/manXYZ mutant strain and biochemical characterization, that this protein specifically facilitates glucose transport, whereas other sugars do not serve as substrates. In addition, we demonstrate pGlcT2-GFP localized to the chloroplast envelope, and that pGlcT2 is mainly produced in seedlings and in the rosette center of mature Arabidopsis plants. Therefore, in conjunction with molecular and metabolic data, we propose pGlcT2 acts as a glucose importer that can limit cytosolic glucose availability in developing pGlcT2-overexpressing seedlings. Finally, we show both overexpression and deletion of pGlcT2 resulted in impaired growth efficiency under long day and continuous light conditions, suggesting pGlcT2 contributes to a release of glucose derived from starch mobilization late in the light phase. Together, these data indicate the facilitator pGlcT2 changes the direction in which it transports glucose during plant development and suggest the activity of pGlcT2 must be controlled spatially and temporarily in order to prevent developmental defects during adaptation to periods of extended light.

Influence of sex and rearing method on performance and flock uniformity in broilers-implications for research settings.

Male and female broiler chickens differ in their growth performance, carcass part weights and nutrient requirements. The potential reasons for these differences have been explored by looking at differences in nutrient digestibility, nutrient transporter gene expression as well as gut microbiota populations between male and female birds. Studies have shown that male broilers have higher crude protein requirements compared to female broilers. The expression of monosaccharide and amino acid transporters show conflicting results as expression depends on the interactions between sex and bird age and breed as well as which tissue is sampled. Differences in microbiota populations between the genders were reported which may contribute towards performance differences, however research in this area is limited. The differences observed between the sexes contribute to increased variation in nutrition trials, and the potential to rear birds as equally mixed-sex becomes an option to reduce the variation introduced by the sex effect. Difference in rearing options obviously would only be feasible provided a quick, practical and cost-effective method of sexing birds is available, a topic that is also discussed in this review.