The rhizosphere microbiome and its influence on the accumulation of metabolites in Bletilla striata (Thunb.) Reichb. f.

BACKGROUND: Bletilla striata (Thunb.) Reichb. f. (B. striata) is a perennial herbaceous plant in the Orchidaceae family known for its diverse pharmacological activities, such as promoting wound healing, hemostasis, anti-inflammatory effects, antioxidant properties, and immune regulation. Nevertheless, the microbe-plant-metabolite regulation patterns for B. striata remain largely undetermined, especially in the field of rhizosphere microbes. To elucidate the interrelationships between soil physics and chemistry and rhizosphere microbes and metabolites, a comprehensive approach combining metagenome analysis and targeted metabolomics was employed to investigate the rhizosphere soil and tubers from four provinces and eight production areas in China. RESULTS: Our study reveals that the core rhizosphere microbiome of B. striata is predominantly comprised of Paraburkholderia, Methylibium, Bradyrhizobium, Chitinophaga, and Mycobacterium. These microbial species are recognized as potentially beneficial for plants health. Comprehensive analysis revealed a significant association between the accumulation of metabolites, such as militarine and polysaccharides in B. striata and the composition of rhizosphere microbes at the genus level. Furthermore, we found that the soil environment indirectly influenced the metabolite profile of B. striata by affecting the composition of rhizosphere microbes. Notably, our research identifies soil organic carbon as a primary driving factor influencing metabolite accumulation in B. striata. CONCLUSION: Our fndings contribute to an enhanced understanding of the comprehensive regulatory mechanism involving microbe-plant-metabolite interactions. This research provides a theoretical basis for the cultivation of high-quality traditional Chinese medicine B. striata.

Advances in the Modulation of Potato Tuber Dormancy and Sprouting.

The post-harvest phase of potato tuber dormancy and sprouting are essential in determining the economic value. The intricate transition from dormancy to active growth is influenced by multiple factors, including environmental factors, carbohydrate metabolism, and hormonal regulation. Well-established environmental factors such as temperature, humidity, and light play pivotal roles in these processes. However, recent research has expanded our understanding to encompass other novel influences such as magnetic fields, cold plasma treatment, and UV-C irradiation. Hormones like abscisic acid (ABA), gibberellic acid (GA), cytokinins (CK), auxin, and ethylene (ETH) act as crucial messengers, while brassinosteroids (BRs) have emerged as key modulators of potato tuber sprouting. In addition, jasmonates (JAs), strigolactones (SLs), and salicylic acid (SA) also regulate potato dormancy and sprouting. This review article delves into the intricate study of potato dormancy and sprouting, emphasizing the impact of environmental conditions, carbohydrate metabolism, and hormonal regulation. It explores how various environmental factors affect dormancy and sprouting processes. Additionally, it highlights the role of carbohydrates in potato tuber sprouting and the intricate hormonal interplay, particularly the role of BRs. This review underscores the complexity of these interactions and their importance in optimizing potato dormancy and sprouting for agricultural practices.

RNA-Seq Reveals That Multiple Pathways Are Involved in Tuber Expansion in Tiger Nuts (Cyperus esculentus L.).

The tiger nut (Cyperus esculentus L.) is a usable tuber and edible oil plant. The size of the tubers is a key trait that determines the yield and the mechanical harvesting of tiger nut tubers. However, little is known about the anatomical and molecular mechanisms of tuber expansion in tiger nut plants. This study conducted anatomical and comprehensive transcriptomics analyses of tiger nut tubers at the following days after sowing: 40 d (S1); 50 d (S2); 60 d (S3); 70 d (S4); 90 d (S5); and 110 d (S6). The results showed that, at the initiation stage of a tiger nut tuber (S1), the primary thickening meristem (PTM) surrounded the periphery of the stele and was initially responsible for the proliferation of parenchyma cells of the cortex (before S1) and then the stele (S2-S3). The increase in cell size of the parenchyma cells occurred mainly from S1 to S3 in the cortex and from S3 to S4 in the stele. A total of 12,472 differentially expressed genes (DEGs) were expressed to a greater extent in the S1-S3 phase than in S4-S6 phase. DEGs related to tuber expansion were involved in cell wall modification, vesicle transport, cell membrane components, cell division, the regulation of plant hormone levels, signal transduction, and metabolism. DEGs involved in the biosynthesis and the signaling of indole-3-acetic acid (IAA) and jasmonic acid (JA) were expressed highly in S1-S3. The endogenous changes in IAA and JAs during tuber development showed that the highest concentrations were found at S1 and S1-S3, respectively. In addition, several DEGs were related to brassinosteroid (BR) signaling and the G-protein, MAPK, and ubiquitin-proteasome pathways, suggesting that these signaling pathways have roles in the tuber expansion of tiger nut. Finally, we come to the conclusion that the cortex development preceding stele development in tiger nut tubers. The auxin signaling pathway promotes the division of cortical cells, while the jasmonic acid pathway, brassinosteroid signaling, G-protein pathway, MAPK pathway, and ubiquitin protein pathway regulate cell division and the expansion of the tuber cortex and stele. This finding will facilitate searches for genes that influence tuber expansion and the regulatory networks in developing tubers.

Programmed Cell Death Reversal: Polyamines, Effectors of the U-Turn from the Program of Death in Helianthus tuberosus L.

This review describes a 50-year-long research study on the characteristics of Helianthus tuberosus L. tuber dormancy, its natural release and programmed cell death (PCD), as well as on the ability to change the PCD so as to return the tuber to a life program. The experimentation on the tuber over the years is due to its particular properties of being naturally deficient in polyamines (PAs) during dormancy and of immediately reacting to transplants by growing and synthesizing PAs. This review summarizes the research conducted in a unicum body. As in nature, the tuber tissue has to furnish its storage substances to grow vegetative buds, whereby its destiny is PCD. The review's main objective concerns data on PCD, the link with free and conjugated PAs and their capacity to switch the destiny of the tuber from a program of death to one of new life. PCD reversibility is an important biological challenge that is verified here but not reported in other experimental models. Important aspects of PA features are their capacity to change the cell functions from storage to meristematic ones and their involvement in amitosis and differentiation. Other roles reported here have also been confirmed in other plants. PAs exert multiple diverse roles, suggesting that they are not simply growth substances, as also further described in other plants.

Transcriptomic analysis of potato (Solanum tuberosum L.) tuber development reveals new insights into starch biosynthesis.

Potato tubers are rich sources of various nutrients and unique sources of starch. Many genes play major roles in different pathways, including carbohydrate metabolism during the potato tuber's life cycle. Despite substantial scientific evidence about the physiological and morphological development of potato tubers, the molecular genetic aspects of mechanisms underlying tuber formation have not yet been fully understood. In this study, for the first time, RNA-seq analysis was performed to shed light on the expression of genes involved in starch biosynthesis during potato tuber development. To this end, samples were collected at the hook-like stolon (Stage I), swollen tips stolon (Stage II), and tuber initiation (Stage III) stages of tuber formation. Overall, 23 GB of raw data were generated and assembled. There were more than 20000 differentially expressed genes (DEGs); the expression of 73 genes involved in starch metabolism was further studied. Moreover, qRT-PCR analysis revealed that the expression profile of the starch biosynthesis DEGs was consistent with that of the RNA-seq data, which further supported the role of the DEGs in starch biosynthesis. This study provides substantial resources on potato tuber development and several starch synthesis isoforms associated with starch biosynthesis.

TCP transcription factor StAST1 represses potato tuberization by regulating tuberigen complex activity.

Potato (Solanum tuberosum L.) is cultivated worldwide for its underground tubers, which provide an important part of human nutrition and serve as a model system for belowground storage organ formation. Similar to flowering, stolon-expressed FLOWERING LOCUS T-like (FT-like) protein SELF-PRUNING 6A (StSP6A) plays an instrumental role in tuberization by binding to the bZIP transcription factors StABI5-like 1 (StABL1) and StFD-like 1 (StFDL1), causing transcriptional reprogramming at the stolon subapical apices. However, the molecular mechanism regulating the widely conserved FT-bZIP interactions remains largely unexplored. Here, we identified a TCP transcription factor StAST1 (StABL1 and StSP6A-associated TCP protein 1) binding to both StSP6A and StABL1. StAST1 is specifically expressed in the vascular tissue of leaves and developing stolons. Silencing of StAST1 leads to accelerated tuberization and a shortened life cycle. Molecular dissection reveals that the interaction of StAST1 with StSP6A and StABL1 attenuates the formation of the alternative tuberigen activation complex (aTAC). We also observed StAST1 directly activates the expression of potato GA 20-oxidase gene (StGA20ox1) to regulate GA responses. These results demonstrate StAST1 functions as a tuberization repressor by regulating plant hormone levels; our findings also suggest a mechanism by which the widely conserved FT-FD genetic module is fine-tuned.

Cassava retting ability and textural attributes of fufu for demand-driven cassava breeding.

BACKGROUND: Cassava retting ability and the textural qualities of cooked fufu are important quality traits. Cassava retting is a complex process in which soaking causes tissue breakdown, starch release, and softening. The rate at which various traits linked to it evolve varies greatly during fufu processing. According to the literature, there is no standard approach for determining retting ability. The retting indices and textural properties of fufu were measured using both manual and instrumental approaches. RESULTS: Different protocols were developed to classify 64 and 11 cassava genotypes into various groups based on retting ability and textural qualities, respectively. The retting protocols revealed considerable genetic dissimilarities in genotype classification: foaming ability and water clarity should be measured at 24 h, while penetrometer, hardness, turbidity, pH, and total titratable acidity data are best collected after 36 h. The stepwise regression model revealed that pH, foaming ability, and dry matter content are the best multivariates (with the highest R2) for predicting cassava retting. These predictors were used to develop an index for assessing the retting ability of cassava genotypes. The retting index developed showed a significant relationship with dry matter content and fufu yield. The study also showed significant correlations between instrumental cohesiveness and sensory smoothness (r = -0.75), moldability (r = -0.62), and stretchability (r = 0.78). Instrumental cohesiveness can correctly estimate fufu smoothness (R2 = 0.56, P = 0.008) and stretchability (R2 = 0.60, P = 0.005). CONCLUSION: pH, foaming ability, and dry matter content are the best traits for predicting cassava retting ability, while instrumental cohesiveness can effectively estimate fufu smoothness and stretchability. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Molecular Insights into the Accelerated Sprouting of and Apical Dominance Release in Potato Tubers Subjected to Post-Harvest Heat Stress.

Climate change-induced heat stress (HS) increasingly threatens potato (Solanum tuberosum L.) production by impacting tuberization and causing the premature sprouting of tubers grown during the hot season. However, the effects of post-harvest HS on tuber sprouting have yet to be explored. This study aims to investigate the effects of post-harvest HS on tuber sprouting and to explore the underlying transcriptomic changes in apical bud meristems. The results show that post-harvest HS facilitates potato tuber sprouting and negates apical dominance. A meticulous transcriptomic profiling of apical bud meristems unearthed a spectrum of differentially expressed genes (DEGs) activated in response to HS. During the heightened sprouting activity that occurred at 15-18 days of HS, the pathways associated with starch metabolism, photomorphogenesis, and circadian rhythm were predominantly suppressed, while those governing chromosome organization, steroid biosynthesis, and transcription factors were markedly enhanced. The critical DEGs encompassed the enzymes pivotal for starch metabolism, the genes central to gibberellin and brassinosteroid biosynthesis, and influential developmental transcription factors, such as SHORT VEGETATIVE PHASE, ASYMMETRIC LEAVES 1, SHOOT MERISTEMLESS, and MONOPTEROS. These findings suggest that HS orchestrates tuber sprouting through nuanced alterations in gene expression within the meristematic tissues, specifically influencing chromatin organization, hormonal biosynthesis pathways, and the transcription factors presiding over meristem fate determination. The present study provides novel insights into the intricate molecular mechanisms whereby post-harvest HS influences tuber sprouting. The findings have important implications for developing strategies to mitigate HS-induced tuber sprouting in the context of climate change.

The tuber-specific StbHLH93 gene regulates proplastid-to-amyloplast development during stolon swelling in potato.

In potato, stolon swelling is a complex and highly regulated process, and much more work is needed to fully understand the underlying mechanisms. We identified a novel tuber-specific basic helix-loop-helix (bHLH) transcription factor, StbHLH93, based on the high-resolution transcriptome of potato tuber development. StbHLH93 is predominantly expressed in the subapical and perimedullary region of the stolon and developing tubers. Knockdown of StbHLH93 significantly decreased tuber number and size, resulting from suppression of stolon swelling. Furthermore, we found that StbHLH93 directly binds to the plastid protein import system gene TIC56 promoter, activates its expression, and is involved in proplastid-to-amyloplast development during the stolon-to-tuber transition. Knockdown of the target TIC56 gene resulted in similarly problematic amyloplast biogenesis and tuberization. Taken together, StbHLH93 functions in the differentiation of proplastids to regulate stolon swelling. This study highlights the critical role of proplastid-to-amyloplast interconversion during potato tuberization.

BEL transcription factors in prominent Solanaceae crops: the missing pieces of the jigsaw in plant development.

MAIN CONCLUSION: Understanding BEL transcription factors roles in potato and tomato varies considerably with little overlap. The review suggests reciprocal use of gained results to proceed with the knowledge in both crops The proper development of organs that plants use for reproduction, like fruits or tubers, is crucial for the survival and competitiveness of the species and thus subject to strict regulations. Interestingly, the controls of potato (Solanum tuberosum) tuber and tomato (S. lycopersicum) fruit development use common mechanisms, including the action of the BEL transcription factors (TFs). Although more than ten BEL genes have been identified in either genome, only a few of them have been characterized. The review summarizes knowledge of BEL TFs' roles in these closely related Solanaceae species, focusing on those that are essential for tuberization in potato, namely StBEL5, StBEL11 and StBEL29, and for fruit development in tomato - SlBEL11, SlBL2 and SIBL4. Comprehension of the roles of individual BEL TFs, however, is not yet sufficient. Different levels of understanding of important characteristics are described, such as BEL transcript accumulation patterns, their mobility, BEL protein interaction with KNOX partners, subcellular localisation, and their target genes during initiation and development of the organs in question. A comparison of the knowledge on BEL TFs and their mechanisms of action in potato and tomato may provide inspiration for faster progress in the study of both models through the exchange of information and ideas. Both crops are extremely important for human nutrition. In addition, their production is likely to be threatened by the upcoming climate change, so there is a particular need for breeding using a deep knowledge of control mechanisms.

Transcriptomic Analyses Reveal the Role of Cytokinin and the Nodal Stem in Microtuber Sprouting in Potato (Solanum tuberosum L.).

In potatoes, tuber secondary growth, especially sprouting, deforms the tubers and severely lowers their commercial value. Tuber sprouting is induced by signal substances, such as gibberellin (GA), which are transported to the tuber from the plant body. The molecular mechanism underlying GA-induced sprouting remains ambiguous. Here, we tried to recreate tuber secondary growth using in vitro stemmed microtubers (MTs) (with the nodal stem attached) and MT halves (with the nodal stem entirely removed). Our experiments showed that GA alone could initiate the sprouting of stemmed microtubers; however, GA failed to initiate MT halves unless 6-benzyladenine, a synthetic cytokinin CK, was co-applied. Here, we analyzed the transcriptional profiles of sprouting buds using these in vitro MTs. RNA-seq analysis revealed a downregulation of cytokinin-activated signaling but an upregulation of the "Zeatin biosynthesis" pathway, as shown by increased expression of CYP735A, CISZOG, and UGT85A1 in sprouting buds; additionally, the upregulation of genes, such as IAA15, IAA22, and SAUR50, associated with auxin-activated signaling and one abscisic acid (ABA) negative regulator, PLY4, plays a vital role during sprouting growth. Our findings indicate that the role of the nodal stem is synonymous with CK in sprouting growth, suggesting that CK signaling and homeostasis are critical to supporting GA-induced sprouting. To effectively control tuber sprouting, more effort is required to be devoted to these critical genes.

Tandem Expression of a Mobile RNA and Its RNA-Binding Protein(s) Enhances Tuber Productivity in Potato.

A significant number of discoveries in past two decades have established the importance of long-distance signaling in controlling plant growth, development, and biotic and abiotic stress responses. Numerous mobile signals, such as mRNAs, proteins, including RNA-binding proteins, small RNAs, sugars, and phytohormones, are shown to regulate various agronomic traits such as flowering, fruit, seed development, and tuberization. Potato is a classic model tuber crop, and several mobile signals are known to govern tuber development. However, it is unknown if these mobile signals have any synergistic effects on potato crop improvement. Here, we employed a simple innovative strategy to test the cumulative effects of a key mobile RNA, StBEL5, and its RNA-binding proteins, StPTB1, and -6 on tuber productivity of two potato cultivars, Solanum tuberosum cv. Désirée and subspecies andigena, using a multi-gene stacking approach. In this approach, the coding sequences of StBEL5 and StPTB1/6 are driven by their respective native promoters to efficiently achieve targeted expression in phloem for monitoring tuber productivity. We demonstrate that this strategy resulted in earliness for tuberization and enhanced tuber productivity by 2-4 folds under growth chamber, greenhouse, and field conditions. This multi-gene stacking approach could be adopted to other crops, whose agronomic traits are governed by mobile macromolecules, expanding the possibilities to develop crops with improved traits and enhanced yields.

StBIN2 Positively Regulates Potato Formation through Hormone and Sugar Signaling.

Potato is an important food crop worldwide. Brassinosteroids (BRs) are widely involved in plant growth and development, and BIN2 (brassinosteroid insensitive 2) is the negative regulator of their signal transduction. However, the function of BIN2 in the formation of potato tubers remains unclear. In this study, transgenic methods were used to regulate the expression level of StBIN2 in plants, and tuber related phenotypes were analyzed. The overexpression of StBIN2 significantly increased the number of potatoes formed per plant and the weight of potatoes in transgenic plants. In order to further explore the effect of StBIN2 on the formation of potato tubers, this study analyzed BRs, ABA hormone signal transduction, sucrose starch synthase activity, the expression levels of related genes, and interacting proteins. The results show that the overexpression of StBIN2 enhanced the downstream transmission of ABA signals. At the same time, the enzyme activity of the sugar transporter and the expression of synthetic genes were increased in potato plants overexpressing StBIN2, which also demonstrated the upregulation of sucrose and the expression of the starch synthesis gene. Apparently, StBIN2 affected the conversion and utilization of key substances such as glucose, sucrose, and starch in the process of potato formation so as to provide a material basis and energy preparation for forming potatoes. In addition, StBIN2 also promoted the expression of the tuber formation factors StSP6A and StS6K. Altogether, this investigation enriches the study on the mechanism through which StBIN2 regulates potato tuber formation and provides a theoretical basis for achieving a high and stable yield of potato.

Molecular characterization of oleosin genes in Cyperus esculentus, a Cyperaceae plant producing oil in underground tubers.

KEY MESSAGE: CeOLE genes exhibit a tuber-predominant expression pattern and their mRNA/protein abundances are positively correlated with oil accumulation during tuber development. Overexpression could significantly increase the oil content of tobacco leaves. Oleosins (OLEs) are abundant structural proteins of lipid droplets (LDs) that function in LD formation and stabilization in seeds of oil crops. However, little information is available on their roles in vegetative tissues. In this study, we present the first genome-wide characterization of the oleosin family in tigernut (Cyperus esculentus L., Cyperaceae), a rare example accumulating high amounts of oil in underground tubers. Six members identified represent three previously defined clades (i.e. U, SL and SH) or six out of seven orthogroups (i.e. U, SL1, SL2, and SH1-3) proposed in this study. Comparative genomics analysis reveals that lineage-specific expansion of Clades SL and SH was contributed by whole-genome duplication and dispersed duplication, respectively. Moreover, presence of SL2 and SH3 in Juncus effuses implies their appearance sometime before Cyperaceae-Juncaceae divergence, whereas SH2 appears to be Cyperaceae specific. Expression analysis showed that CeOLE genes exhibit a tuber-predominant expression pattern and transcript levels are considerably more abundant than homologs in the close relative Cyperus rotundus. Moreover, CeOLE mRNA and protein abundances were shown to positively correlate with oil accumulation during tuber development. Additionally, two dominant isoforms (i.e. CeOLE2 and -5) were shown to locate in LDs as well as the endoplasmic reticulum of tobacco (Nicotiana benthamiana) leaves, and are more likely to function in homo and heteromultimers. Furthermore, overexpression of CeOLE2 and -5 in tobacco leaves could significantly increase the oil content, supporting their roles in oil accumulation. These findings provide insights into lineage-specific family evolution and putative roles of CeOLE genes in oil accumulation of vegetative tissues, which facilitate further genetic improvement for tigernut.

Carbohydrate metabolism dynamic in chlorpropham- and 1,4-dimethylnaphthalene-treated potatoes and its effect on the browning of French fries.

The use of a sprout suppressor is crucial for the use of potatoes beyond their natural dormancy period. The main sprout inhibitor used on a commercial scale, chlorpropham (CIPC), is becoming increasingly limited owing to its toxicity. Therefore, we evaluated the effectiveness of 1,4-dimethylnaphthalene (1,4-DMN) compared to CIPC in controlling sprouting and maintaining the quality of potato, Solanum tuberosum 'Asterix', during cold storage. Treatment with 1,4-DMN reduced fresh weight loss and controlled the number and length of sprouts comparable to CIPC. Compared to the control, both sprouting inhibitors led to higher starch and lower reducing sugar contents, and the tubers retained the recommended quality for industrial processing. After frying, less browning was observed in French fries obtained from 1,4-DMN- or CIPC-treated tubers. We ascertain that 1,4-DMN besides being an efficient sprouting inhibitor and alternative to CIPC, it contributes to maintaining the quality of French fries after cold storage.

The Expression of the StNRAMP2 Gene Determined the Accumulation of Cadmium in Different Tissues of Potato.

Cadmium (Cd) is a toxic metal that threatens human health when enriched in crops. NRAMPs are a family of natural macrophage proteins reported to play a key role in Cd transport in plants. In order to explore the gene regulation mechanism of potato under Cd stress and the role of NRAMPs family in it, this study analyzed the gene expression differences of two different Cd accumulation levels in potato after 7 days of 50 mg/kg Cd stress and screened out the key genes that may play a major role in the differential accumulation of Cd in different varieties. Additionally, StNRAMP2 was selected for verification. Further verification showed that the StNRAMP2 gene plays an important role in the accumulation of Cd in potato. Interestingly, silencing StNRAMP2 increased Cd accumulation in tubers but significantly decreased Cd accumulation in other sites, suggesting a critical role of StNRAMP2 in Cd uptake and transport in potatoes. To further confirm this conclusion, we performed heterologous expression experiments in which overexpression of StNRAMP2 gene in tomato resulted in a threefold increase in Cd content, which further confirmed the important role of StNRAMP2 in the process of Cd accumulation compared with wild-type plants. In addition, we found that the addition of Cd to the soil increased the activity of the plant antioxidant enzyme system, and silencing StNRAMP2 partially reversed this effect. This suggests that the StNRAMP2 gene plays an important role in plant stress tolerance, and future studies could further explore the role of this gene in other environmental stresses. In conclusion, the results of this study improve the understanding of the mechanism of Cd accumulation in potato and provide experimental basis for remediation of Cd pollution.

Investigating the genetic components of tuber bruising in a breeding population of tetraploid potatoes.

BACKGROUND: Tuber bruising in tetraploid potatoes (Solanum tuberosum) is a trait of economic importance, as it affects tubers' fitness for sale. Understanding the genetic components affecting tuber bruising is a key step in developing potato lines with increased resistance to bruising. As the tetraploid setting renders genetic analyses more complex, there is still much to learn about this complex phenotype. Here, we used capture sequencing data on a panel of half-sibling populations from a breeding programme to perform a genome-wide association analysis (GWAS) for tuber bruising. In addition, we collected transcriptomic data to enrich the GWAS results. However, there is currently no satisfactory method to represent both GWAS and transcriptomics analysis results in a single visualisation and to compare them with existing knowledge about the biological system under study. RESULTS: When investigating population structure, we found that the STRUCTURE algorithm yielded greater insights than discriminant analysis of principal components (DAPC). Importantly, we found that markers with the highest (though non-significant) association scores were consistent with previous findings on tuber bruising. In addition, new genomic regions were found to be associated with tuber bruising. The GWAS results were backed by the transcriptomics differential expression analysis. The differential expression notably highlighted for the first time the role of two genes involved in cellular strength and mechanical force sensing in tuber resistance to bruising. We proposed a new visualisation, the HIDECAN plot, to integrate the results from the genomics and transcriptomics analyses, along with previous knowledge about genomic regions and candidate genes associated with the trait. CONCLUSION: This study offers a unique genome-wide exploration of the genetic components of tuber bruising. The role of genetic components affecting cellular strength and resistance to physical force, as well as mechanosensing mechanisms, was highlighted for the first time in the context of tuber bruising. We showcase the usefulness of genomic data from breeding programmes in identifying genomic regions whose association with the trait of interest merit further investigation. We demonstrate how confidence in these discoveries and their biological relevance can be increased by integrating results from transcriptomics analyses. The newly proposed visualisation provides a clear framework to summarise of both genomics and transcriptomics analyses, and places them in the context of previous knowledge on the trait of interest.

Inulin: properties and health benefits.

Inulin, a soluble dietary fiber, is widely found in more than 36 000 plant species as a reserve polysaccharide. The primary sources of inulin, include Jerusalem artichoke, chicory, onion, garlic, barley, and dahlia, among which Jerusalem artichoke tubers and chicory roots are often used as raw materials for inulin production in the food industry. It is universally acknowledged that inulin as a prebiotic has an outstanding effect on the regulation of intestinal microbiota via stimulating the growth of beneficial bacteria. In addition, inulin also exhibits excellent health benefits in regulating lipid metabolism, weight loss, lowering blood sugar, inhibiting the expression of inflammatory factors, reducing the risk of colon cancer, enhancing mineral absorption, improving constipation, and relieving depression. In this review paper, we attempt to present an exhaustive overview of the function and health benefits of inulin.

Mechanical wounds expedited starch degradation in the wound tissues of potato tubers.

Starch degradation occurs rapidly in stressed plants, but it is unclear how starch degradation occurs in potato tubers after they incur mechanical wounding. In this study, we found that wounding significantly upregulated the expression levels of StGWD, StAMY, StBAM, and StISA, and decreased the starch content of potato tubers. Meanwhile, wounding markedly upregulated the expression levels of StSUS, StBG, and StINV genes, and increased the content of sucrose, glucose, and fructose. Furthermore, wounding reduced the proportion of small starch granules and increase that of large as well as medium starch granules, in this way enhancing the average size distribution of starch. Initially, the hard surface layer of starch granules was removed by wounding, but the internal channels and other structures were only slightly affected. Taken together, the results show that wounding can accelerate starch degradation by promoting the accumulation of sucrose, glucose, and fructose, and the hydrolysis of starch granules in potato tubers.

Long-distance control of potato storage organ formation by SELF PRUNING 3D and FLOWERING LOCUS T-like 1.

Plants program their meristem-associated developmental switches for timely adaptation to a changing environment. Potato (Solanum tuberosum L.) tubers differentiate from specialized belowground branches or stolons through radial expansion of their terminal ends. During this process, the stolon apex and closest axillary buds enter a dormancy state that leads to tuber eyes, which are reactivated the following spring and generate a clonally identical plant. The potato FLOWERING LOCUS T homolog SELF-PRUNING 6A (StSP6A) was previously identified as the major tuber-inducing signal that integrates day-length cues to control the storage switch. However, whether some other long-range signals also act as tuber organogenesis stimuli remains unknown. Here, we show that the florigen SELF PRUNING 3D (StSP3D) and FLOWERING LOCUS T-like 1 (StFTL1) genes are activated by short days, analogously to StSP6A. Overexpression of StSP3D or StFTL1 promotes tuber formation under non-inductive long days, and the tuber-inducing activity of these proteins is graft transmissible. Using the non-tuber-bearing wild species Solanum etuberosum, a natural SP6A null mutant, we show that leaf-expressed SP6A is dispensable for StSP3D long-range activity. StSP3D and StFTL1 mediate secondary activation of StSP6A in stolon tips, leading to amplification of this tuberigen signal. StSP3D and StFTL1 were observed to bind the same protein partners as StSP6A, suggesting that they can also form transcriptionally active complexes. Together, our findings show that additional mobile tuber-inducing signals are regulated by the photoperiodic pathway.