Rice Transcription Factor OsDOF11 Modulates Sugar Transport by Promoting Expression of Sucrose Transporter and SWEET Genes

Transcription Factor CitERF16 Is Involved in Citrus Fruit Sucrose Accumulation by Activating CitSWEET11d

Sugars are the primary products of photosynthesis and play an important role in plant growth and development. They contribute to sweetness and flavor of fleshy fruits and are pivotal to fruit quality, and their translocation and allocation are mainly dependent on sugar transporters. Genome-wide characterization of Satsuma mandarin identified eighteen SWEET family members that encode transporters which facilitate diffusion of sugar across cell membranes. Analysis of the expression profiles in tissues of mandarin fruit at different developmental stages showed that CitSWEET11d transcripts were significantly correlated with sucrose accumulation. Further studies indicated that overexpression of CitSWEET11d in citrus callus and tomato fruit showed a higher sucrose level compared to wild-type, suggesting that CitSWEET11d could enhance sucrose accumulation. In addition, we identified an ERF transcription factor CitERF16 by yeast one-hybrid screening assay which could directly bind to the DRE cis-element on the promoter of CitSWEET11d. Overexpression of CitERF16 in citrus callus significantly induced CitSWEET11d expression and elevated sucrose content, suggesting that CitERF16 acts as a positive regulator to promote sucrose accumulation via trans-activation of CitSWEET11d expression.

Monocotyledonous plants graft at the embryonic root-shoot interface

Grafting is possible in both animals and plants. Although in animals the process requires surgery and is often associated with rejection of non-self, in plants grafting is widespread, and has been used since antiquity for crop improvement¹. However, in the monocotyledons, which represent the second largest group of terrestrial plants and include many staple crops, the absence of vascular cambium is thought to preclude grafting². Here we show that the embryonic hypocotyl allows intra- and inter-specific grafting in all three monocotyledon groups: the commelinids, lilioids and alismatids. We show functional graft unions through histology, application of exogenous fluorescent dyes, complementation assays for movement of endogenous hormones, and growth of plants to maturity. Expression profiling identifies genes that unify the molecular response associated with grafting in monocotyledons and dicotyledons, but also gene families that have not previously been associated with tissue union. Fusion of susceptible wheat scions to oat rootstocks confers resistance to the soil-borne pathogen Gaeumannomyces graminis. Collectively, these data overturn the consensus that monocotyledons cannot form graft unions, and identify the hypocotyl (mesocotyl in grasses) as a meristematic tissue that allows this process. We conclude that graft compatibility is a shared ability among seed-bearing plants.

Ancient rapid functional differentiation and fixation of the duplicated members in rice Dof genes after whole genome duplication

Whole genome duplication (WGD) in plants is typically followed by genomic downsizing, where large portions of the new genome are lost. Whether this downsizing is accompanied by increased or decreased evolutionary rates of the remaining genes is poorly known, not least because homeolog pairings are often obscured by chromosomal rearrangement. Here, we use the newly published genome from a sedge, namely Kobresia littledalei, and CRISPR/Cas-9 editing to investigate how the Rho WGD event 70 million years ago (MYA) affected transcription factor evolutionary rates, fates, and function in rice (Oryza sativa) and sorghum (Sorghum bicolor). We focus on the 30-member DNA-binding with one zinc finger (Dof) transcription factor family in both crops due to their agronomic importance. Using the known speciation dates of rice from Kobresia (97 MYA) and sorghum (50 MYA), we find that rates of amino acid substitution in the critical Dof domain region were over twofold higher during the 20-million-year period following the WGD than before or afterward. Through comparison of synteny blocks, we report that at least 11% of Dof genes were purged from 70 to 50 MYA, while only 6% have been lost in the most recent 50-million-year interval. CRISPR/Cas9 editing revealed widespread fitness-related defects in flowering and lack of redundancy of paired members, as well as significant differences in expression between gene pairs. Together these findings demonstrate the strength of Dof genes as a model for deep evolutionary study and offer one of the most detailed portraits yet of the Rho WGD impact on a gene lineage.

The Role of Membrane Transporters in Plant Growth and Development, and Abiotic Stress Tolerance

The proteins of membrane transporters (MTs) are embedded within membrane-bounded organelles and are the prime targets for improvements in the efficiency of water and nutrient transportation. Their function is to maintain cellular homeostasis by controlling ionic movements across cellular channels from roots to upper plant parts, xylem loading and remobilization of sugar molecules from photosynthesis tissues in the leaf (source) to roots, stem and seeds (sink) via phloem loading. The plant's entire source-to-sink relationship is regulated by multiple transporting proteins in a highly sophisticated manner and driven based on different stages of plant growth and development (PG&D) and environmental changes. The MTs play a pivotal role in PG&D in terms of increased plant height, branches/tiller numbers, enhanced numbers, length and filled panicles per plant, seed yield and grain quality. Dynamic climatic changes disturbed ionic balance (salt, drought and heavy metals) and sugar supply (cold and heat stress) in plants. Due to poor selectivity, some of the MTs also uptake toxic elements in roots negatively impact PG&D and are later on also exported to upper parts where they deteriorate grain quality. As an adaptive strategy, in response to salt and heavy metals, plants activate plasma membranes and vacuolar membrane-localized MTs that export toxic elements into vacuole and also translocate in the root's tips and shoot. However, in case of drought, cold and heat stresses, MTs increased water and sugar supplies to all organs. In this review, we mainly review recent literature from Arabidopsis, halophytes and major field crops such as rice, wheat, maize and oilseed rape in order to argue the global role of MTs in PG&D, and abiotic stress tolerance. We also discussed gene expression level changes and genomic variations within a species as well as within a family in response to developmental and environmental cues.

Sucrose transporter in rice

Plant photosynthesis processes play vital roles in crop plant development. Understanding carbohydrate partitioning via sugar transport is one of the potential ways to modify crop biomass, which is tightly linked to plant architecture, such as plant height and panicle size. Based on the literature, we highlight recent findings to summarize phloem loading by sucrose transport in rice. In rice, sucrose transporters, OsSUTs (sucrose transporters) and OsSWEETs (sugars are eventually exported transporters) import sucrose and export cells between phloem parenchyma cells and companion cells. Before sucrose transporters perform their functions, several transcription factors can induce sucrose transporter gene transcription levels, such as Oryza sativa DNA binding with one finger 11 (OsDOF11) and Oryza sativa Nuclear Factor Y B1 (OsNF-YB1). In addition to native regulator genes, environmental factors, such as CO₂ concentration, drought stress and increased temperature, also affect sucrose transporter gene transcription levels. However, more research work is needed on formation regulation webs. Elucidation of the phloem loading mechanism could improve our understanding of rice development under multiple conditions and facilitate its manipulation to increase crop productivity.

Sugar transporters in grasses: Function and modulation in source and storage tissues

Carbohydrate partitioning, the process of transporting carbohydrates from photosynthetic (source) tissues, such as leaves, to non-photosynthetic (sink) tissues, such as stems, roots, and reproductive structures, is vital not only for the growth and development of plants but also for withstanding biotic and abiotic stress. In many plants, sucrose is the primary form of carbohydrate loaded into the phloem for long-distance transport and unloaded into the sink tissues for utilization or storage. We highlight recent findings about 1) phloem loading in grasses, 2) the principal families of sugar transporters involved in sucrose transport, and 3) novel mechanisms by which the activities of sugar transporters are modulated. We discuss exciting discoveries from eudicot species that provide valuable insights regarding the regulation of these sugar transporters, which may be translatable to monocot species. As we better understand the intricate pathways that control the activities of various sugar transporters, we can utilize this knowledge for developing improved crop varieties.

Rice SUT and SWEET Transporters

Sugar transporters play important or even indispensable roles in sugar translocation among adjacent cells in the plant. They are mainly composed of sucrose-proton symporter SUT family members and SWEET family members. In rice, 5 and 21 members are identified in these transporter families, and some of their physiological functions have been characterized on the basis of gene knockout or knockdown strategies. Existing evidence shows that most SUT members play indispensable roles, while many SWEET members are seemingly not so critical in plant growth and development regarding whether their mutants display an aberrant phenotype or not. Generally, the expressions of SUT and SWEET genes focus on the leaf, stem, and grain that represent the source, transport, and sink organs where carbohydrate production, allocation, and storage take place. Rice SUT and SWEET also play roles in both biotic and abiotic stress responses in addition to plant growth and development. At present, these sugar transporter gene regulation mechanisms are largely unclear. In this review, we compare the expressional profiles of these sugar transporter genes on the basis of chip data and elaborate their research advances. Some suggestions concerning future investigation are also proposed.

OsDOF11 Affects Nitrogen Metabolism by Sucrose Transport Signaling in Rice (Oryza sativa L.)

Carbon and nitrogen antagonistically regulate multiple developmental processes. However, the molecular mechanism affecting nitrogen metabolism by sucrose transport remains poorly defined. Previously, we noted that Oryza sativa DNA BINDING WITH ONE FINGER 11 (OsDOF11) mediated sucrose transport by binding to the promoter regions of Sucrose Transporter 1 (SUT1), Oryza sativa Sugars Will Eventually be Exported Transporters 11 (OsSWEET11), and OsSWEET14. Here, we note that OsDOF11 promotes nitrogen uptake and then maintains the ratio of fresh weight to dry weight in seedling plants and the effective leaf blade at flowering stages. Mutants of the sucrose transporter gene OsSWEET14 displayed a phenotype similar to that of OsDOF11. By microarray analysis and qRT-PCR in OsDOF11 mutant plants, OsDOF11 affected the transcription level of amino acid metabolism-related genes. We further found that mainly amino acid contents were reduced in flag leaves but increased in seeds. Both sugar and organic nitrogen changes caused the ratio of fresh weight to dry weight to decrease in OsDOF11 mutant seedling plants and mature leaves, which might result in vigorous reduced metabolic activity and become less susceptible to stress. These results demonstrated that OsDOF11 affected nitrogen metabolism by sugar distribution in rice, which provided new insight that OsDOF11 coordinated with C and N balance to maintain plant growth activity.

Ethylene response factors regulate expression of HbSUT3, the sucrose influx carrier in laticifers of Hevea brasiliensis

Natural rubber is an important industrial raw material and is commercially produced by rubber trees (Hevea brasiliensis). The sucrose transporter HbSUT3 plays an essential role in rubber production. Its expression in latex (cytoplasm of rubber-producing laticifers) is induced by bark treatment with Ethrel, an ethylene releaser, and the inducing effect correlates well with Ethrel-stimulated rubber yield increase. However, the mechanisms of ethylene induction on HbSUT3 expression are not known. Here, five Ethylene Response Factor (ERF) genes were identified from the cDNA library of Hevea latex by yeast one-hybrid screening with the promoter of HbSUT3 gene as bait. As revealed in a tobacco (Nicotiana tabacum) protoplast transient expression system, these HbERFs were mainly localized in the nucleus and four of them exhibited apparent transactivation activity. Of the five HbERF genes, HbERF-IXc4 was the most frequently screened in yeast one-hybrid, accounting for 65% of the ERF clones obtained. Moreover, among the five HbERFs, HbERF-IXc4 showed the strongest transactivation capacity when expressed in tobacco protoplast, the highest transcript abundance in latex and a close expressional correlation with its target gene, HbSUT3, in response to the Ethrel treatment. Taken together, our results indicate that ERFs, especially HbERF-IXc4, are critically involved in the activation of HbSUT3 expression in latex after Ethrel treatment on Hevea bark, and thus the stimulated latex yield.

Evidence for phloem loading via the abaxial bundle sheath cells in maize leaves

Leaves are asymmetric, with different functions for adaxial and abaxial tissue. The bundle sheath (BS) of C3 barley (Hordeum vulgare) is dorsoventrally differentiated into three types of cells: adaxial structural, lateral S-type, and abaxial L-type BS cells. Based on plasmodesmatal connections between S-type cells and mestome sheath (parenchymatous cell layer below bundle sheath), S-type cells likely transfer assimilates toward the phloem. Here, we used single-cell RNA sequencing to investigate BS differentiation in C4 maize (Zea mays L.) plants. Abaxial BS (abBS) cells of rank-2 intermediate veins specifically expressed three SWEET sucrose uniporters (SWEET13a, b, and c) and UmamiT amino acid efflux transporters. SWEET13a, b, c mRNAs were also detected in the phloem parenchyma (PP). We show that maize has acquired a mechanism for phloem loading in which abBS cells provide the main route for apoplasmic sucrose transfer toward the phloem. This putative route predominates in veins responsible for phloem loading (rank-2 intermediate), whereas rank-1 intermediate and major veins export sucrose from the PP adjacent to the sieve element companion cell complex, as in Arabidopsis thaliana. We surmise that abBS identity is subject to dorsoventral patterning and has components of PP identity. These observations provide insights into the unique transport-specific properties of abBS cells and support a modification to the canonical phloem loading pathway in maize.

Phloem loading in rice leaves depends strongly on the apoplastic pathway

Phloem loading is the first step in sucrose transport from source leaves to sink organs. The phloem loading strategy in rice remains unclear. To determine the potential phloem loading mechanism in rice, yeast invertase (INV) was overexpressed by a 35S promoter specifically in the cell wall to block sugar transmembrane loading in rice. The transgenic lines exhibited obvious phloem loading suppression characteristics accompanied by the accumulation of sucrose and starch, restricted vegetative growth and decreased grain yields. The decreased sucrose exudation rate with p-chloromercuribenzenesulfonic acid (PCMBS) treatment also indicated that rice actively transported sucrose into the phloem. OsSUT1 (SUCROSE TRANSPORTER 1) showed the highest mRNA levels of the plasma membrane-localized OsSUTs in source leaves. Cross sections of the OsSUT::GUS transgenic plants showed that the expression of OsSUT1 and OsSUT5 occurred in the phloem companion cells. Rice ossut1 mutants showed reduced growth and grain yield, supporting the hypothesis of OsSUT1 acting in phloem loading. Based on these results, we conclude that apoplastic phloem loading plays a major role in the export of sugar from rice leaves.

Genome-wide analysis and functional characterization of the Dof transcription factor family in rice (Oryza sativa L.)

Exhaustive searches of the rice genome have revealed 30 different potential OsDof (Oryza sativa DNA binding with One Finger) genes. Their subcellular localization, phylogenetic relationship, conserved motifs identification, chromosomal allocation, expression patterns, and interaction networks were analyzed. The Dof (DNA binding with One Finger) family of transcription factors represents a particular class of plant-specific transcriptional regulators, contain a highly conserved region of 50-52 amino acids (Dof domain) and involved in various plant developmental processes and response to various environmental stresses. Few (Oryza sativa) OsDof genes have been demonstrated previously for their biological functions but there is no comprehensive study on most of the Dof genes of rice. In the current study, exhaustive searches of the rice genome revealed 30 different potential OsDof genes, and then their subcellular localization, phylogenetic relationship, conserved motifs identification, chromosomal allocation, expression patterns, and interaction networks were analyzed. Phylogenetic analysis of Dof proteins in rice showed that they are distributed in 4 groups. By genome-wide observation of gene expression profiles, we found that OsDof genes showed significant variances in expression levels in different tissues across multiple developmental stages. Protein-protein correlation network analysis, shows a statically significant overlap of some OsDofs, suggesting their similar functions and a high degree of co-expression. The Dof family transcription factors have been reported for their involvement in the regulation of various gene expression processes in rice but still, most of the Dof genes are not characterized for their specific physiological functions. This study revealed useful information and clues about predicting the potential roles of OsDofs in rice by combining their genome-wide characterization, expression profiling, protein-protein interactions, and for further studies to develop high-quality rice varieties.

Sucrose transport in response to drought and salt stress involves ABA-mediated induction of OsSWEET13 and OsSWEET15 in rice

Abiotic stresses, including drought and salinity, negatively affect plant development and physiology at molecular and metabolic levels. Sucrose transport, mediating distribution of photosynthates in plant, is a key physiological process impacted by drought and salinity stresses, as sucrose is a prime energy and signaling molecule as well as an osmolyte. Therefore, understanding the effects of abiotic stresses on sucrose transport and transporters, and underlying genetic and molecular mechanisms, is imperative to maintain sugar homeostasis in plants under stress. Here, we investigated the effects of drought and salinity stresses on sucrose transport and distribution, and on expression levels of genes encoding Sugars Will Eventually be Exported Transporters (SWEETs), along with a potential transcription factor regulating SWEET expression in rice. We observed that drought and salinity stresses increased the sucrose content in leaf and root tissues and in phloem sap of rice indica varieties. Expression analyses of SWEET genes and histochemical analysis of β-glucuronidase-reporter transgenic plants suggested that OsSWEET13 and OsSWEET15 are major SWEET transporters regulating the sucrose transport and levels in response to the abiotic stresses. Transactivation analyses showed that an abscisic acid (ABA)-responsive transcription factor OsbZIP72 directly binds to the promoters of OsSWEET13 and OsSWEET15 and activates their expression. Taken together, the results showed that the higher expressions of OsSWEET13 and OsSWEET15 genes, induced by binding of an ABA-responsive transcription factor OsbZIP72 to the promoters, potentially modulate sucrose transport and distribution in response to the abiotic stresses. The mechanism could possibly be targeted for maintaining sugar homeostasis in rice under drought and salinity stresses.

Nitrogen fertilizer-regulated plant-fungi interaction is related to root invertase-induced hexose generation

The mechanisms underlying nitrogen (N)-regulated plant-fungi interactions are not well understood. N application modulates plant carbohydrate (C) sinks and is involved in the overall plant-fungal association. We hypothesized that N regulates plant-fungi interactions by influencing the carbohydrate metabolism. The mutualistic fungus Phomopsis liquidambaris was found to prioritize host hexose resources through in vitro culture assays and in planta inoculation. Rice-Ph. liquidambaris systems were exposed to N gradients ranging from N-deficient to N-abundant conditions to study whether and how the sugar composition was involved in the dynamics of N-mediated fungal colonization. We found that root soluble acid invertases were activated, resulting in increased hexose fluxes in inoculated roots. These fluxes positively influenced fungal colonization, especially under N-deficient conditions. Further experiments manipulating the carbohydrate composition and root invertase activity through sugar feeding, chemical treatments and the use of different soil types revealed that the external disturbance of root invertase could reduce endophytic colonization and eliminate endophyte-induced host benefits under N-deficient conditions. Collectively, these results suggest that the activation of root invertase is related to N deficiency-enhanced endophytic colonization via increased hexose generation. Certain combinations of farmland ecosystems with suitable N inputs could be implemented to maximize the benefits of plant-fungi associations.

Identification and Expression Analysis of the SWEET Gene Family from Poa pratensis Under Abiotic Stresses

The sugars will eventually be exported transporters (SWEET) gene family is a glycoprotein gene family that can regulate the transport of sugar in plants and plays an important role in plant growth and development, as well as in response to environmental stress. In this study, Kentucky bluegrass (cv. Baron) seedlings were grown in various treatments, including heavy metal cadmium, salt, drought, cold, and heat stress for 6 h, 24 h, 48 h, and 7 day. The relative expression of the identified PpSWEET genes in Kentucky bluegrass was measured. The results showed there were a total of 13 SWEET genes, which could be divided into four clades by phylogenetic analysis. Most PpSWEET genes are alkali proteins with seven transmembrane helices. Moreover, almost all PpSWEET proteins possess similar conserved motifs and active sites. In addition, an analysis of the relative expression of PpSWEET genes under various stress treatments indicated that PpSWEET12 and PpSWEET15 had very high expression under the five types of stress, meaning they can be used as important candidate genes for studying responses to environmental stresses of turfgrass. Furthermore, certain genes only showed changes in expression under one or two specific stress treatments. This study provides important insight into the SWEET gene family in Kentucky bluegrass and its functional roles in responses to various environmental stresses.

The versatile functions of OsALDH2B1 provide a genic basis for growth-defense trade-offs in rice

In plants, enhanced defense often compromises growth and development, which is regarded as trade-offs between growth and defense. Here we identified a gene, OsALDH2B1, that functions as a master regulator of the growth-defense trade-off in rice. OsALDH2B1 has its primary function as an aldehyde dehydrogenase and a moonlight function as a transcriptional regulator. Loss of function of OsALDH2B1 greatly enhanced resistance to broad-spectrum pathogens, including fungal blast, bacterial leaf blight, and leaf streak, but caused severe phenotypic changes such as male sterility and reduced plant size, grain size, and number. We showed that its primary function as a mitochondrial aldehyde dehydrogenase conditions male fertility. Its moonlight function of transcriptional regulation, featuring both repressing and activating activities, regulates a diverse range of biological processes involving brassinolide, G protein, jasmonic acid, and salicylic acid signaling pathways. Such regulations cause large impacts on the morphology and immunity of rice plants. The versatile functions of OsALDH2B1 provide an example of the genic basis of growth-defense trade-offs in plants.

OsRRM, an RNA-Binding Protein, Modulates Sugar Transport in Rice (Oryza sativa L.)

Sugar allocation between vegetative and reproductive tissues is vital to plant development, and sugar transporters play fundamental roles in this process. Although several transcription factors have been identified that control their transcription levels, the way in which the expression of sugar transporter genes is controlled at the posttranscriptional level is unknown. In this study, we showed that OsRRM, an RNA-binding protein, modulates sugar allocation in tissues on the source-to-sink route. The OsRRM expression pattern partly resembles that of several sugar transporter and transcription factor genes that specifically affect sugar transporter gene expression. The messenger RNA levels of almost all of the sugar transporter genes are severely reduced in the osrrm mutant, and this alters sugar metabolism and sugar signaling, which further affects plant height, flowering time, seed size, and starch synthesis. We further showed that OsRRM binds directly to messenger RNAs encoded by sugar transporter genes and thus may stabilize their transcripts. Therefore, we have uncovered the physiological function of OsRRM, which sheds new light on sugar metabolism and sugar signaling.

Mutagenesis in Rice: The Basis for Breeding a New Super Plant

The high selection pressure applied in rice breeding since its domestication thousands of years ago has caused a narrowing in its genetic variability. Obtaining new rice cultivars therefore becomes a major challenge for breeders and developing strategies to increase the genetic variability has demanded the attention of several research groups. Understanding mutations and their applications have paved the way for advances in the elucidation of a genetic, physiological, and biochemical basis of rice traits. Creating variability through mutations has therefore grown to be among the most important tools to improve rice. The small genome size of rice has enabled a faster release of higher quality sequence drafts as compared to other crops. The move from structural to functional genomics is possible due to an array of mutant databases, highlighting mutagenesis as an important player in this progress. Furthermore, due to the synteny among the Poaceae, other grasses can also benefit from these findings. Successful gene modifications have been obtained by random and targeted mutations. Furthermore, following mutation induction pathways, techniques have been applied to identify mutations and the molecular control of DNA damage repair mechanisms in the rice genome. This review highlights findings in generating rice genome resources showing strategies applied for variability increasing, detection and genetic mechanisms of DNA damage repair.

Structure, evolution and diverse physiological roles of SWEET sugar transporters in plants

Present review describes the structure, evolution, transport mechanism and physiological functions of SWEETs. Their application using TALENs and CRISPR/CAS9 based genomic editing approach is discussed. Sugars Will Eventually be Exported Transporters (SWEET) proteins were first identified in plants as the novel family of sugar transporters which mediates the translocation of sugars across cell membranes. The SWEET family of sugar transporters is unique in terms of their structure which contains seven predicted transmembrane domains with two internal triple-helix bundles which possibly originate due to prokaryotic gene duplication. SWEETs perform diverse physiological functions such as pollen nutrition, nectar secretion, seed filling, phloem loading, and pathogen nutrition which we have discussed in the present review. We also discuss how transcriptional activator-like effector nucleases (TALENs) and CRISPR/CAS9 genome editing tools are used to engineer SWEET mutants which modulate pathogen resistance in plants and its applications in the field of agriculture. The expression of SWEETs promises to implement insights into many other cellular transport mechanisms. To conclude, the present review highlights the recent aspects which will further develop better understanding of molecular evolution, structure, and function of SWEET transporters in plants.

Source-Sink Regulation Is Mediated by Interaction of an FT Homolog with a SWEET Protein in Potato

Potato plants form tuberous storage organs on underground modified stems called stolons. Tubers are rich in starch, proteins, and other important nutrients, making potato one of the most important staple food crops. The timing of tuber development in wild potato is regulated by day length through a mechanism that is closely related to floral transition [1, 2]. Tuberization is also known to be regulated by the availability of assimilates, in particular sucrose, the transported form of sugar, required for starch synthesis. During the onset of tuber development, the mode of sucrose unloading switches from apoplastic to symplastic [3]. Here, we show that this switch may be mediated by the interaction between the tuberization-specific FT homolog StSP6A and the sucrose efflux transporter StSWEET11 [4]. The binding of StSP6A to StSWEET11 blocked the leakage of sucrose to the apoplast, and is therefore likely to promote symplastic sucrose transport. The direct physical interaction between StSWEET11 and StSP6A proteins represents a link between the sugar and photoperiodic pathways for the regulation of potato tuber formation. Our data suggest that a previously undiscovered function for the FT family of proteins extends their role as mobile signals to mediators of source-sink partitioning, opening the possibility for modifying source-sink interactions.

Sucrose transport involves in disease response to Xanthomonas oryzae pathovar oryzae

Sugar acts as an important nutrient for plant development. Previously, we reported that Oryza sativa DNA BINDING WITH ONE FINGER 11 (OsDOF11) plays a crucial role in sucrose transport by binding promoters of sucrose transporter genes, OsSUT1, OsSWEET11, and OsSWEET14. Meanwhile, sucrose transport activity abnormal also involved susceptibility to infection of Xanthomonas oryzae pathovar oryzae (Xoo) by OsSWEET genes. Here, we provid an addendum, that OsDOF11 expression pattern in spikelet development stage, and transcript levels of OsSWEET12, OsSWEET13, OsSWEET15, and OsSWEET16 in the mutants of OsDOF11 at different developmental stages. This information further supplied a new insight that sucrose transport activity mediated susceptibility to Xoo infection.

The Sugar-Signaling Hub: Overview of Regulators and Interaction with the Hormonal and Metabolic Network

Plant growth and development has to be continuously adjusted to the available resources. Their optimization requires the integration of signals conveying the plant metabolic status, its hormonal balance, and its developmental stage. Many investigations have recently been conducted to provide insights into sugar signaling and its interplay with hormones and nitrogen in the fine-tuning of plant growth, development, and survival. The present review emphasizes the diversity of sugar signaling integrators, the main molecular and biochemical mechanisms related to the sugar-signaling dependent regulations, and to the regulatory hubs acting in the interplay of the sugar-hormone and sugar-nitrogen networks. It also contributes to compiling evidence likely to fill a few knowledge gaps, and raises new questions for the future.

The Sugar-Signaling Hub: Overview of Regulators and Interaction with the Hormonal and Metabolic Network

Plant growth and development has to be continuously adjusted to the available resources. Their optimization requires the integration of signals conveying the plant metabolic status, its hormonal balance, and its developmental stage. Many investigations have recently been conducted to provide insights into sugar signaling and its interplay with hormones and nitrogen in the fine-tuning of plant growth, development, and survival. The present review emphasizes the diversity of sugar signaling integrators, the main molecular and biochemical mechanisms related to the sugar-signaling dependent regulations, and to the regulatory hubs acting in the interplay of the sugar-hormone and sugar-nitrogen networks. It also contributes to compiling evidence likely to fill a few knowledge gaps, and raises new questions for the future.