Effects of mepiquat chloride and plant population density on leaf photosynthesis and carbohydrate metabolism in upland cotton

Background Mepiquat chloride(MC)application and plant population density(PPD)increasing are required for modern cotton production.However,their interactive effects on leaf physiology and carbohydrate metabolism remain obscure.This study aimed to examine whether and how MC and PPD affect the leaf morpho-physiological characteristics,and thus final cotton yield.PPD of three levels(D1:2.25 plants·m^(-2),D2:4.5 plants·m^(-2),and D3:6.75 plants·m^(-2))and MC dosage of two levels(MC0:0 g·ha^(-2),MC1:82.5 g·ha^(-2))were combined to create six treatments.The dynamics of nonstructual carbohydrate concentration,carbon metabolism-related enzyme activity,and photosynthetic attributes in cotton leaves were examined during reproductive growth in 2019 and 2020.Results Among six treatments,the high PPD of 6.75 plants·m^(-2)combined with MC application(MC1D3)exhibited the greatest seed cotton yield and biological yield.The sucrose,hexose,starch,and total nonstructural carbohydrate(TNC)concentrations peaked at the first flowering(FF)stage and then declined to a minimum at the first boll opening(FBO)stage.Compared with other treatments,MC1D3 improved starch and TNC concentration by 5.4%~88.4%,7.8%~52.0% in 2019,and by 14.6%~55.9%,13.5%~39.7% in 2020 at the FF stage,respectively.Additionally,MC1D3 produced higher transformation rates of starch and TNC from the FF to FBO stages,indicating greater carbon production and utilization efficiency.MC1D3 displayed the maximal specific leaf weight(SLW)at the FBO stage,and the highest chlorophyll a(Chl a),Chl b,and Chl a+b concentration at the mid-late growth phase in both years.The Rubisco activity with MC1D3 was 2.6%~53.2% higher at the flowering and boll setting stages in both years,and 2.4%~52.7% higher at the FBO stage in 2020 than those in other treatments.These results provided a explanation of higher leaf senescence-resistant ability in MC1D3.Conclusion Increasing PPD coupled with MC application improves cotton yield by enhancing leaf carbohydrate production and utilization efficiency and delaying leaf senescence.

Chrysoeriol ameliorates hyperglycemia by regulating the carbohydrate metabolic enzymes in streptozotocin-induced diabetic rats

The present study aimed to evaluate the effects of chrysoeriol from Cardiospermum halicacabum in streptozotocin induced Wistar rats.Thirty rats were categorized as control,diabetic control supplemented with 0,20 mg/kg chrysoeriol and 600μg/kg BW of glibenclamide for 45-day trial period.Our results indicated that the inclusion of chrysoeriol(20 mg/kg)showed a significant reduction in plasma glucose,hemoglobin and glycosylated hemoglobin level with a rising of plasma insulin sensitivity.Further,downregulated enzymes including glucose 6-phosphatase,fructose 1,6-bisphosphatase,and glycogen phosphorylase as well upregulated enzymes such as hexokinase,glucose-6-phosphate dehydrogenase,pyruvate kinase,and hepatic glycogen content.There was a diminish action found in liver glycogen synthase of tested rat with a rise in gamma-glutamyl transpeptidase,towards normal levels upon treatment with chrysoeriol.The histopathological study confirmed that renewal of the beta cells of pancreatic of chrysoeriol and glibenclamide treated rats.In addition,the molecular docking of chrysoeriol against glycolytic enzymes including hexokinase,glucose-6-phosphate dehydrogenase,pyruvate kinase,using Argus software shows chrysoeriol had greatest ligand binding energy as equivalent to glibenclamide,as a standard drug.Thus,chrysoeriol found to be non-toxic with potential regulation on glycemic control and upregulation of the carbohydrate metabolic enzymes.

Selenium Alleviates Carbohydrate Metabolism and Nutrient Composition in Arsenic Stressed Rice Plants

This study reported the influence of selenium(Se)on carbohydrate composition and some related enzymes and nutrient compositions of arsenic(As)stressed rice plants.Rice plants of cultivar PR126 were grown on soil amended with As in a range of 25-100μmol/kg with and without 0.5 or 1.0 mg/kg Se.Total soluble sugars(TSS)and reducing sugars(RS)increased in leaves of As stressed plants at the tillering and grain filling stages whereas sucrose and starch contents showed the reverse trend.Se supplementation to As stressed plants further increased TSS and RS,and enhanced sucrose phosphate synthase activity in rice leaves,thus improving sucrose content and the tolerance to As stress of the plants.Se alone or in combination with As resulted in lower As accumulation in rice husk and grains,and the highest reduction was observed in Se applied at 1.0 mg/kg compared to the corresponding As treatments alone.As may limit the accumulations of Na,Mg,K,Ca,Fe,Zn and Mn in rice grains,which are essential for humans.Binary application of different combinations of As and Se protected the plants against As and increased the mineral content in rice grains.Addition of Se in As treated soil significantly alleviated As stress by enhancing grain yields compared to the corresponding As treatment.It is concluded that Se induced amelioration of the toxic impact of As in rice either by modulating carbohydrate composition and/or nutrient uptake is one of the mechanisms to alleviate As stress in plants.

Response of carbohydrate metabolism-mediated sink strength to auxin in shoot tips of apple plants

Auxin(indole-3-acetic acid, IAA) has a considerable impact on the regulation of plant carbohydrate levels and growth, but the mechanism by which it regulates sugar levels in plants has received little attention. In this study, we found that exogenous IAA altered fructose(Fru), glucose(Glc), and sucrose(Suc) concentrations in shoot tips mainly by regulating MdSUSY1, MdFRK2, MdHxK1 and MdSDH2 transcript levels. Additionally, we used 5-year-old ’Royal Gala’ apple trees to further verify that these genes play primary roles in regulating sink strength. The results showed that MdSUSY1, MdFRK2, MdHxK1/3 and MdSDH2 might be major contributors to sink strength regulation. Taken together, these results provide new insight into the regulation of the carbohydrate metabolism mechanism, which will be helpful for regulating sink strength and yield.

PCSK9 and carbohydrate metabolism:A double-edged sword

Proprotein convertase subtilisin/kexin type 9(PCSK9) plays a paramount role in the degradation of lowdensity lipoprotein(LDL) receptors(LDLR) on the hepatic cells surface and subsequently affects LDL particles catabolism and LDL cholesterol(LDL-c) levels. The anti-PCSK9 monoclonal antibodies lead to substantial decrease of LDL-c concentration. PCSK9(which is also expressed in pancreatic delta-cells) can decrease LDLR and subsequently decrease cholesterol accumulation in pancreatic beta-cells, which impairs glucose metabolism and reduces insulin secretion. Thus, a possible adverse effect of PCSK9 inhibitors on carbohydrate metabolism may be expected by this mechanism, which has been supported by the mendelian studies results. On the other hand, clinical data have suggested a detrimental association of PCSK9 with glucose metabolism. So, the inhibition of PCSK9 may be seen as a double-edged sword regarding carbohydrate metabolism. Completed clinical trials have not shown a detrimental effect of PCSK9 inhibitors on diabetes risk, but their short-term duration does not allow definite conclusions.

Changes of carbohydrate and protein metabolism in seedling leaves of a temperature-induced greenable albino mutant line W25 of rice

W25 is a low-temperature-sensitive albino mu-tant line. Temperature not only controls thealbino phenotype expression of W25, but alsodetermines whether it could survive. When thetemperature is lower than 25℃, the leaves ofW25 shows complete albino, but they exhibitsnormal green when temperature is higher than30℃. Meanwhile, at 25℃, it can be greenable

Is intraspecific trait differentiation in Parthenium hysterophorus a consequence of hereditary factors and/or phenotypic plasticity?

Of the various strategies adopted by an invasive plant species for expanding its niche breadth,phenotypic differentiation(either due to plasticity and/or adaptive evolution) is proven to be the most successful.Lately,we studied the persistence of substantial morpho-functional variations within the individuals of alien invasive plant,Parthenium hysterophorus in Chandigarh,India,through field surveys.Based on observed differences,the individuals were categorized into two morphotypes,PAand PB.PAhad higher leaf area,leaf biomass,and chlorophyll content as compared with PB.However,PBhad a higher stem circumference,stem specific density,twig dry matter content,profuse branching,bigger canopy,and better reproductive output than PA.To substantiate the persistence of intraspecific variations in P. hysterophorus and to deduce the possible genesis of these variations,we propagated both the morphotypes under experimental conditions in winter and summer.Apart from the key morpho-functional differences observed during the field studies,protein and carbohydrate metabolism were studied in leaves and roots of the propagated plants.Differences in plant metabolism were observed only during the early growth period,whereas the morpho-functional traits varied in the mature flowering plants.The effect of growth season was highly significant on all the studied morpho-functional and biochemical parameters(p ≤0.05).Parent morphotypes(P) and interactions between morphotypes and seasons significantly affected several growth parameters(p ≤0.05).The analyses revealed that the contrasting growth conditions at the time of transplantation and early growth may regulate the phenotype of P. hysterophorus.The pattern of intraspecific variations observed during the study is justified to consider morphotype PAas winter biotype and morphotype PBas summer biotype of P. hysterophorus.The study points towards the role of plasticity or a combination of genetic and environmental(G×E) factors in producing the phenotypic variability observed in the population of P. hysterophorus.

Bionics and Structural Biology:A Novel Approach for Bio-energy Production

Cellular metabolism is a very complex process. The biochemical pathways are fundamental structures of biology. These pathways possess a number of regeneration steps which facilitate energy shuttling on a massive scale. This facilitates the biochemical pathways to sustain the energy currency of the cells. This concept has been mimicked using electronic circuit components and it has been used to increase the efficiency of bio-energy generation. Six of the carbohydrate biochemical pathways have been chosen in which glycolysis is the principle pathway. All the six pathways are interrelated and coordinated in a complex manner. Mimic circuits have been designed for all the six biochemical pathways. The components of the metabolic pathways such as enzymes, cofactors etc., are substituted by appropriate electronic circuit components. Enzymes are related to the gain of transistors by the bond dissociation energies of enzyme-substrate molecules under consideration. Cofactors and coenzymes are represented by switches and capacitors respectively. Resistors are used for proper orientation of the circuits. The energy obtained from the current methods employed for the decomposition of organic matter is used to trigger the mimic circuits. A similar energy shuttle is observed in the mimic circuits and the percentage rise for each cycle of circuit functioning is found to be 78.90. The theoretical calculations have been made using a sample of domestic waste weighing 1.182 kg. The calculations arrived at finally speak of the efficiency of the novel methodology employed.

Bioinformatics Analysis of HKDC1 Expression in Non-small Cell Lung Cancer and Its Relationship to Survival

Lung cancer has become one of the most common types of cancer,and has the highest morbidity and mortality rates.We herein performed a bioinformatic analysis to explore the gene expression of hexokinase domain containing 1(HKDC1)to further illuminate the molecular mechanisms involved in non-small cell lung cancer(NSCLC).We also examined the relationship between HKDC1 expression and patient survival.The Oncomine and cBioPortal cancer genomics databases were used to investigate the expression of HKDC1 in NSCLC.Then the protein-protein interaction network and protein expression intensity of HKDC1 were examined with the Gene MANIA and The Human Protein Atlas databases.Finally,the prognostic impact of HKDC1 was evaluated via the GEPIA,Oncolnc and Kaplan-Meier Plotter online tools.HKDC1 was significantly up-regulated in NSCLC patients.In addition,the mutation frequency of HKDC1 in NSCLC was high in a large number of studies.Moreover,HKDC1 expression was correlated with a poor prognosis in NSCLC patients.These findings suggest that HKDC1 represents a novel therapeutic target for NSCLC.

Insulin Resistance in Pregnancy Is Correlated with Decreased Insulin Receptor Gene Expression in Omental Adipose: Insulin Sensitivity and Adipose Tissue Gene Expression in Normal Pregnancy

Aims: To determine correlations of insulin sensitivity to gene expression in omental and subcutaneous adipose tissue of non-obese, non-diabetic pregnant women. Methods: Microarray gene profiling was performed on subcutaneous and omental adipose tissue from 14 patients and obtained while fasting during non-laboring Cesarean section, using Illumina HumanHT-12 V4 Expression BeadChips. Findings were validated by real-time PCR. Matusda-Insulin sensitivity index (IS) and homeostasis model assessment of insulin resistance (HOMA-IR) were calculated from glucose and insulin levels obtained from a frequently sampled oral glucose tolerance test, and correlated with gene expression. Results: Of genes differentially expressed in omental vs. subcutaneous adipose, in omentum 12 genes were expressed toward insulin resistance, whereas only 5 genes were expressed toward insulin sensitivity. In particular, expression of the insulin receptor gene (INSR), which initiates the insulin signaling cascade, is strongly positively correlated with IS and negatively with HOMA-IR in omental tissue (r = 0.84). Conclusion: Differential gene expression in omentum relative to subcutaneous adipose showed a pro-insulin resistance profile in omentum. A clinical importance of omental adipose is observed here, as downregulation of insulin receptor in omentum is correlated with increased systemic insulin resistance.

Effects of Salt Stress on Carbohydrate Metabolism in Desert Soil Alga Microcoleus vaginatus Gom

The effects of salt stress on carbohydrate metabolism in Microcoleus vaginatus Gom., a cyanobacterium isolated from desert algal crusts, were investigated in the present study. Extracellular total carbohydrates and exopolysaccharides （EPS） in the culture medium produced by M. vaginatus increased significantly during the growth phase and reached a maximum during the stationary phase. The production of extracellular carbohydrates also significantly increased under higher salt concentrations, which was attributed to an increase in low molecular weight carbohydrates. In the presence of NaCI, the production of cellular total carbohydrates decreased and photosynthetic activity was impaired, whereas cellular reducing sugars, water-soluble sugars and sucrose content and sucrose phosphate synthase activity increased, reaching a maximum in the presence of 200 mmol/L NaCI. These parameters were restored to original levels when the algae were transferred to a non-saline medium. Sodium and K＋ concentrations of stressed cells decreased significantly and H＋-ATPase activity increased after the addition of exogenous sucrose or EPS. The results suggest that EPS and sucrose are synthesized to maintain the cellular osmOtic equilibrium between the intra-and extracellular environment, thus protecting algal cells from osmotic damage, which was attributed to the selective exclusion of cellular Na＋ and K＋ by H＋-ATPase.

EFFECT OF ANTIHYDATID DRUGS ON CARBOHYDRATE METABOLISM OF METACESTODE OF ECHINOCOCCUS GRANULOSUS

A biochemical some enzymes of glycolysis and a partial reversed tricarboxylic acid cycle together with hydrolytic enzymes in the cyst wall of Echinococcus granulosus was carried out. Lactate dehydrogenase (LDH), pyruvate kinase (PK), phosphoenolpyruvate carboxykinase (PEPCK), and adenosine triphosphatase (ATPase) showed their high level of activity, suggesting that the proliferation of E. granulosus cyst wall is an energy-dependent process and the major pathways for glucose metabolism is glycolysis. Treatment of E. granulosus-in-fected mice with mebendazole and albendazole resulted in marked inhibition of PK, PEPCK and ATPase of E. granulosus cyst wall, whereas praziquantel had no effect, indicating that PK, PEPCK, and ATPase might be chemotherapeutic targets and the differences in the inhibitory effects might account for the efficacy of the three antihydatid drugs.

A Transcriptomic Analysis of Physiological Significance of Hypoxia-inducible Factor-1α in Myogenesis and Carbohydrate Metabolism of Genioglossus in Mice

Background： Chronic intermittent hypoxia is the most remarkable feature of obstructive sleep apnea/hypopnea syndrome and it can induce the change of hypoxia-inducible factor-1α （H IF-1α） expression and contractile properties in the genioglossus. To clarify the role of HIF-lot in contractile properties of the genioglossus, this study generated and compared high-throughput RNA-sequencing data from genioglossus between HIF-1α conditional knockout （KO） mice and littermate wild-type （WT） mice. Methods： KO mice were generated with cre-loxP strategy. Gene expression profile analysis was performed using gene enrichment analysis. Gene ontology （GO） and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway analyses of differently expressed messenger RNAs were performed to identify the related pathways and biological lhnctions. Six differentially expressed genes （DEGs） were validated by qualitative reverse transcription polymerase chain reaction. Results： A total of 142 （77 upregulated and 65 downregulated） transcripts were found to exhibit statistically significant difference between the HIF-la-KO and WT mice. GO and KEGG analyses indicated that DEGs included genes involved in ＂skeletal muscle cell differentiation,＂ ＂muscle organ development,＂ ＂glucose metabolic process,＂ ＂glycogen biosynthetic and metabolic process,＂ etc. Conclusion： This study might provide evidence that H IF-lot affects the expression of multiple genes involved in the myogenesis, muscle developrnent, and carbohydrate metabolism through transcriptome analysis in conditional HIE-1α-KO mice.

New insights into the influence of myo-inositol on carbohydrate metabolism during osmoregulation in Nile tilapia (Oreochromis niloticus)

A two-factor(23)orthogonal testwas conducted to investigate the effects of dietary myo-inositol(MI)on the osmoregulation and carbohydrate metabolism of euryhaline fish tilapia(Oreochromis niloticus)under sustained hypertonic stress(20 practical salinity units[psu]).6 diets containing either normal carbohydrate(NC,30%)or high carbohydrate(HC,45%)levels,with 3 levels(0,400 and 1,200 mg/kg diet)of MI,respectively,were fed to 540 fish under 20 psu for 8 weeks.Dietary MI supplementation significantly improved growth performance and crude protein content of whole fish,and decreased the content of crude lipid of whole fish(P<0.05).Curled,disordered gill lamella and cracked gill filament cartilage were observed in the gill of fish fed diets without MI supplementation.The ion transport capacity in gill was significantly improved in the 1,200 mg/kg MI supplementation groups compared with the 0 mg/kg MI groups(P<0.05).Moreover,the contents of Na^(+),K^(+),Cl^(-)in serum weremarkedly reduced with the dietary MI supplementation(P<0.05).The fish fed 1,200 mg/kg MI supplementation had the highest MI content in the gills and the lowest MI content in the serum(P<0.05).Additionally,the fish fed with 1,200 mg/kg MI supplementation had the highest MI synthesis capacity in gills and brain(P<0.05).Dietary MI markedly promoted the ability of carbohydrate metabolism in liver(P<0.05).Moreover,fish in the 1,200 mg/kg MI groups had the highest antioxidant capacity(P<0.05).This study indicated that high dietary carbohydrate would intensify stress,and impair the ability of osmoregulation in tilapia under a long-term hypersaline exposure.The supplementation of MI at 1,200 mg/kg in the high carbohydrate diet could promote carbohydrate utilization and improve the osmoregulation capacity of tilapia under long-term hypertonic stress.

Metabolism of carbohydrate in alimentary tract of reindeer in winter

The study was conducted on six reindeers in December.It was established that concentration of reducing sugars in the chyme of jejunum increases substantially(6 times in comparison with abomasum),whereas concentration cellulose,on the contrary,decreases(4.5 times).The maximal increase of monosaccharides in the small intestine testifies to formation of metabolic fund of sugars in this part of the alimentary tract due to high degree of polysaccharides hydrolysis of exogenous,as well as endogenous,microbial formation.Obtained data assume that the need of the reindeer for glucose is provided for not only by gluconeogenesis as it was considered before,but also by absorption of monosaccharides from the alimentary tract.

Nanotandem-rocket releases messenger to disrupt metabolic communication for antitumor immunotherapy

Metabolic communication between intracellular metabolism and extracellular microenvironment is responsible for celluar metabolism balance and cell survival.Tumor cells adaptively regulate metabolic communication to promote hyperproliferation and immunosuppression.Herein,nanotandem-rockets(hyaluronic acid modified Mg_(5)(CO_(3))_(4)(OH)_(2)(H-MCH))are developed for stepwisely disrupting metabolic communication to activate antitumor immunity.Benefiting from the nanotandem-rocket structure,H-MCH nanoplates successively disrupt the extracellular metabolite transport and intracellular carbohydrate metabolism.Theoretical simulation together with metabolomic analysis discloses the underlying mechanism of H-MCH nanotandem-rockets.The extra-/intra-celluar interruption of metabolic communication provides H-MCH nanotandem-rockets with high efficiency in tumor eradication.Moreover,the interference of metabolic communication reverses immunosuppression to facilitate the intratumoral infiltration of immune cells.With H-MCH nanotandem-rockets as an in situ vaccine,systemic antitumor immunity and immune memory effect are fabricated to eliminate tumor metastasis and recurrence.Different from traditional metabolic poisons(e.g.,arsenic or cyanide),the structure of nanotandem-rockets endows chemical messengers with selective regulation to tumor metabolic communication,but with minimal influence to normal tissues.The nanotandem-rockets provide a powerful paltform to augment the regulating actitiy of chemical messengers in metabolic communication.We expect our discovery of disrupting tumor metabolic communication with chemical messengers will be a powerful strategy for tumor therapy with vast practical applications.

Gut bacterium promotes host fitness in special ecological niche by affecting sugar metabolism in Drosophila suzukii

As an important fruit pest of global significance,Drosophila suzukii occupies a special ecological niche,with the characteristics of high sugar and low protein contents.This niche differs from those occupied by other fruit-damaging Drosophila species.Gut bacteria substantially impact the physiology and ecology of insects.However,the contribution of gut microbes to the fitness of D.suzukii in their special ecological niche remains unclear.In this study,the effect of Klebsiella oxytoca on the development of D.suzukii was examined at physiological and molecular levels.The results showed that,after the removal of gut microbiota,the survival rate and longevity of axenic D.suzukii decreased significantly.Reintroduction of K.oxytoca to the midgut of D.suzukii advanced the development level of D.suzukii.The differentially expressed genes and metabolites between axenic and K.oxytoca-reintroduced D.suzukii were enriched in the pathways of carbohydrate metabolism.This advancement was achieved through an increased glycolysis rate and the regulation of the transcript level of key genes in the glycolysis/gluconeogenesis pathway.Klebsiella oxytoca is likely to play an important role in increasing host fitness in their high-sugar ecological niche by stimulating the glycolysis/gluconeogenesis pathway.As a protein source,bacteria can also provide direct nutrition for D.suzukii,which depends on the quantity or biomass of K.oxytoca.This result may provide a new target for controlling D.suzukii by inhibiting sugar metabolism through eliminating the effect of K.oxytoca and thus disrupting the balance of gut microbial communities.

Metabolic changes during larval–pupal metamorphosis of Helicoverpa armigera

Energy metabolism is essential for insect metamorphosis. The accumulation and utilization of energy is still not completely clear during larval–pupal metamorphosis of holometabolous insects. We used metabolome and transcriptome analysis to reveal key metabolic changes in the fat body and plasma and the underlying metabolic regulation mechanism of Helicoverpa armigera, an important global agricultural insect pest, during larval–pupal metamorphosis. During the feeding stage, activation of aerobic glycolysis provided intermediate metabolites and energy for cell proliferation and lipid synthesis. During the non-feeding stages (the initiation of the wandering stage and the prepupal stage), aerobic glycolysis was suppressed, while, triglyceride degradation was activated in the fat body. The blocking of metabolic pathways in the fat body was probably caused by 20-hydroxyecdysone-induced cell apoptosis. 20-hydroxyecdysone cooperated with carnitine to promote the degradation of triglycerides and the accumulation of acylcarnitines in the hemolymph, allowing rapid transportation and supply of lipids from the fat body to other organs, which provided a valuable reference for revealing the metabolic regulation mechanism of lepidopteran larvae during the last instar. Carnitine and acylcarnitines are first reported to be key factors that mediate the degradation and utilization of lipids during larval–pupal metamorphosis of lepidopteran insects.

Membrane-Transport Systems for Sucrose in Relation to Whole-Plant Carbon Partitioning

Sucrose is the principal product of photosynthesis used for the distribution of assimilated carbon in plants. Transport mechanisms and efficiency influence photosynthetic productivity by relieving product inhibition and contribute to plant vigor by controlling source/sink relationships and biomass partitioning. Sucrose is synthesized in the cytoplasm and may move cell to cell through plasmodesmata or may cross membranes to be compartmentalized or exported to the apoplasm for uptake into adjacent cells. As a relatively large polar compound, sucrose requires proteins to facilitate efficient membrane transport. Transport across the tonoplast by facilitated diffusion, antiport with protons, and symport with protons have been proposed; for transport across plasma membranes, symport with protons and a mechanism resembling facilitated diffusion are evident. Despite decades of research, only symport with protons is well established at the molecular level. This review aims to integrate recent and older studies on sucrose flux across membranes with principles of whole-plant carbon partitioning.

Homogalacturonan MethyI-Esterification and Plant Development

The ability of a plant cell to expand is largely defined by the physical constraints imposed by its cell wall. Accordingly, cell wall properties have to be regulated during development. The pectic polysaccharide homogalacturonan is a major component of the plant primary walls. Biosynthesis and in muro modification of homogalacturonan have recently emerged as key determinants of plant development, controlling cell adhesion, organ development, and phyllotactic patterning. This review will focus on recent findings regarding impact of homogalacturonan content and methylesterification status of this polymer on plant life. Demethyl-esterification of homogalacturonan occurs through the action of the ubiquitous enzyme ＇pectin methyl-esterase＇. We here describe various strategies developed by the plant to finely tune the methyl-esterification status of homogalacturonan along key events of the plant lifecycle.