Pharmacokinetic Properties of Baitouweng Decoction in Bama Miniature Pigs: Implications for Clinical Application in Humans.

Traditional Chinese medicine (TCM) serves as a significant adjunct to chemical treatment for chronic diseases. For instance, the administration of Baitouweng decoction (BTWD) has proven effective in the treatment of ulcerative colitis. However, the limited understanding of its pharmacokinetics (PK) has impeded its widespread use. Chinese Bama miniature pigs possess anatomical and physiological similarities to the human body, making them a valuable model for investigating PK properties. Consequently, the identification of PK properties in Bama miniature pigs can provide valuable insights for guiding the clinical application of BTWD in humans. To facilitate this research, a rapid and sensitive UPLC-MS/MS method has been developed for the simultaneous quantification of eleven active ingredients of BTWD in plasma. Chromatographic separation was conducted using an Acquity UPLC HSS T3 C18 column and a gradient mobile phase comprising acetonitrile and water (containing 0.1% acetic acid). The methodology was validated in accordance with the FDA Bioanalytical Method Validation Guidance for Industry. The lower limit of quantitation fell within the range of 0.60-2.01 ng/mL. Pharmacokinetic studies indicated that coptisine chloride, berberine, columbamine, phellodendrine, and obacunone exhibited low Cmax, while fraxetin, esculin, fraxin, and pulchinenoside B4 were rapidly absorbed and eliminated from the plasma. These findings have implications for the development of effective components in BTWD and the adjustment of clinical dosage regimens.

TLC-Bioautography-Guided Isolation and Assessment of Antibacterial Compounds from Manuka (Leptospermum scoparium) Leaf and Branch Extracts.

A rapid procedure for the targeted isolation of antibacterial compounds from Manuka (Leptospermum scoparium) leaf and branch extracts was described in this paper. Antibacterial compounds from three different Manuka samples collected from New Zealand and China were compared. The active compounds were targeted by TLC-bioautography against S. aureus and were identified by HR-ESI-MS, and -MS/MS analysis in conjunction with Compound Discoverer 3.3. The major antibacterial component, grandiflorone, was identified, along with 20 ß-triketones, flavonoids, and phloroglucinol derivatives. To verify the software identification, grandiflorone underwent purification via column chromatography, and its structure was elucidated through NMR analysis, ultimately confirming its identity as grandiflorone. This study successfully demonstrated that the leaves and branches remaining after Manuka essential oil distillation serve as excellent source for extracting grandiflorone. Additionally, we proposed an improved TLC-bioautography protocol for evaluating the antibacterial efficacy on solid surfaces, which is suitable for both S. aureus and E. coli. The minimum effective dose (MED) of grandiflorone was observed to be 0.29-0.59 µg/cm2 against S. aureus and 2.34-4.68 µg/cm2 against E. coli, respectively. Furthermore, the synthetic plant growth retardant, paclobutrazol, was isolated from the samples obtained in China. It is hypothesized that this compound may disrupt the synthesis pathway of triketones, consequently diminishing the antibacterial efficacy of Chinese Manuka extract in comparison to that of New Zealand.

An improved MTT colorimetric method for rapid viable bacteria counting.

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay has been employed in the analysis of bacterial growth. In comparison to experiments conducted on mammalian cells, the MTT bacterial assay encounters a greater number of interfering factors and obstacles that impact the accuracy of results. In this study, we have elucidated an improved MTT assay protocol and put forth an equation that establishes a correlation between colony-forming units (CFU) and the amount of formazan converted by the bacteria, drawing upon the fundamental principle of the MTT assay. This equation is represented as CFU=kF. Furthermore, we have explicated a methodology to determine the scale factor "k" by employing S. aureus and E. coli as illustrative examples. The findings indicate that S. aureus and E. coli reduce MTT by a cyclic process, from which the optimal reduction time at room temperature was determined to be approximately 30 mins. Furthermore, individual E. coli exhibits an MTT reduction capacity approximately four times greater than that of S. aureus. HPLC analysis proves to be the most accurate method for mitigating interferences during the dissolution and quantification of formazan. Additionally, this study has identified a new constraint related to the narrow linear range (0-125 µg/mL) of formazan concentration-absorbance and has presented strategies to circumvent this limitation.

The DUF288 domain containing proteins GhSTLs participate in cotton fiber cellulose synthesis and impact on fiber elongation.

Cotton is one of the most important economic crops in the world, with over 90 % cellulose in the mature fiber. However, the cellulose synthesis mechanism in cotton fibers is poorly understood. Here, we identified four DUF288 domain containing proteins, which we designated GhSTL1-4. These four GhSTL genes are highly expressed in 6 days post anthesis (dpa) and 20 dpa cotton fibers. They are localized to the Golgi apparatus, and can rescue the growth defects in primary cell wall (PCW) and secondary cell wall (SCW) of cellulose synthesis of the Arabidopsis stl1stl2 double mutant at varying degrees. Silencing of GhSTLs resulted in reduced cellulose content and shorter fibers. In addition, split-ubiquitin membrane yeast two-hybrid analysis showed that GhSTL1 and GhSTL4 can interact with PCW-related GhCesA6-1/6-3 and SCW-associated GhCesA7-1/7-2. GhSTL3 can interact with SCW-related GhCesA4-3. These interactions are further confirmed by firefly luciferase complementation imaging assay. Together, we demonstrate that GhSTLs can selectively interact with both the PCW and SCW-associated GhCesAs and impact on cellulose synthesis and fiber development. Our findings provide insights into the mechanism underlying cellulose biosynthesis in cotton fibers, and offer potential candidate genes to coordinate PCW and SCW cellulose synthesis of cotton fibers for developing elite cotton varieties with enhanced fiber quality.

GhMYB7 promotes secondary wall cellulose deposition in cotton fibres by regulating GhCesA gene expression through three distinct cis-elements.

Cotton fibre is the most important source for natural textiles. The secondary cell walls (SCWs) of mature cotton fibres contain the highest proportion of cellulose content (> 90%) in any plant. The onset and progression of SCW cellulose synthesis need to be tightly controlled to balance fibre elongation and cell wall deposition. However, regulatory mechanisms that control cellulose synthesis during cotton fibre growth remain elusive. Here, we conducted genetic and functional analyses demonstrating that the R2R3-MYB GhMYB7 controls cotton fibre cellulose synthesis. Overexpression of GhMYB7 in cotton sped up SCW cellulose biosynthesis in fibre cells, and led to shorter fibres with thicker walls. By contrast, RNA interference (RNAi) silencing of GhMYB7 delayed fibre SCW cellulose synthesis and resulted in elongated fibres with thinner walls. Furthermore, we demonstrated that GhMYB7 regulated cotton fibre SCW cellulose synthases by directly binding to three distinct cis-elements in the respective GhCesA4, GhCesA7 and GhCesA8 promoters. We found that this regulatory mechanism of cellulose synthesis was 'hi-jacked' also by other GhMYBs. Together, our findings uncover a hitherto-unknown mechanism that cotton fibre employs to regulate SCW cellulose synthesis. Our results also provide a strategy for genetic improvement of SCW thickness of cotton fibre.

De novosynthesis of pH-responsive, self-assembled, and targeted polypeptide nano-micelles for enhanced delivery of doxorubicin.

Doxorubicin (DOX) is a commonly used anticancer drug, but it is inefficient as a therapeutic due to a lack of targeting. Peptide-tuned self-assembly of DOX offers a strategy to improve targeting for greater efficacy. In this work, we designed and prepared an amphiphilic tumor cell-targeting peptide, P14 (AAAAFFFHHHGRGD), able to encapsulate DOX by self-assembly to form tumor cell-targeting and pH-sensitive nano-micelles. The results showed a critical P14-micelle concentration of 1.758 mg l-1and an average particle size of micelles of 121.64 nm, with entrapment and drug-loading efficiencies of 28.02% ± 1.35% and 12.06% ± 0.59%, respectively. The prepared micelles can release 73.52 ± 1.27% DOX within 24 h in pH 4.5 medium, and the drug cumulative release profile of micelles can be described by the first-order model. Compared with free DOX, the micelles exhibited an increased ability to inhibit tumor cell growth and cause tumor apoptosisin vitro, with IC50values of DOX and P14-DOX micelles against human breast cancer cells (MCF-7) of 0.91 ± 0.07 and 0.75 ± 0.06µg ml-1, respectively, and cellular apoptotic rates of DOX and P14-DOX micelles of 70.3% and 42.4%, respectively. Cellular uptake experiments revealed high concentrations of micelles around and inside MCF-7 cells, demonstrating that micelles can target tumor cells. These results indicate the excellent potential for the application of this amphiphilic peptide as a carrier for small-molecule drugs and suggest a strategy for the design of effective anti-tumor drugs.

Genome-Wide Identification of the HD-ZIP III Subfamily in Upland Cotton Reveals the Involvement of GhHB8-5D in the Biosynthesis of Secondary Wall in Fiber and Drought Resistance.

A subfamily of transcription factors known as HD-ZIP III plays distinct roles in the secondary cell wall biosynthesis, which could be attributed to the quality of cotton fiber and adaptation to drought stress. In this study, 18 HD-ZIP III genes were identified as genome wide from the upland cotton (Gossypium hirsutum). These genes are distributed on 14 different chromosomes, and all of them have undergone segmental duplications. Numerous cis-elements were identified in the promoter regions, which are related to phytohormone responses and abiotic stresses. Expression profiling of these genes by quantitative real-time (qRT)-PCR illustrated their differential spatial expression, with preferential expression in cotton fiber. Among these genes, GhHB8-5D was predicted to encode a protein that is targeted to the cell nucleus and having self-activation ability. In addition, the ectopic expression of GhHB8-5D or its synonymous mutant GhHB8-5Dm in Arabidopsis resulted in stunted plant growth, curly leaves, and twisted inflorescence stems. Microscopy examination revealed that the morphology of vascular bundles and deposition of secondary wall had substantially altered in stems, which is concomitant with the significant alteration in the transcription levels of secondary wall-related genes in these transgenic Arabidopsis. Further, ectopic expression of GhHB8-5D or GhHB8-5Dm in Arabidopsis also led to significant increase in green seedling rate and reduction in root length relative to wild type when the plants were grown under mimicked drought stress conditions. Taken together, our results may shed new light on the functional roles of GhHB8-5D that is attributable for secondary cell wall thickening in response to drought stress. Such a finding may facilitate a novel strategy for improving plant adaptations to environmental changes via regulating the biosynthesis of secondary cell wall.

A cotton NAC domain transcription factor, GhFSN5, negatively regulates secondary cell wall biosynthesis and anther development in transgenic Arabidopsis.

NAC domain transcription factors (TFs) are plant-specific transcriptional regulators, some of which play crucial roles in secondary cell wall (SCW) biosynthesis in plants. Cotton is one of the most important natural fiber producing crops, whose mature fiber SCW contains more than 90% cellulose with very small amounts of xylan and lignin, but little is known about the molecular mechanism underlying fiber SCW formation. We previously identified seven fiber preferentially expressed NAC members, GhFSN1-7. One, GhFSN1, was demonstrated to positively regulate fiber SCW thickening, but the functions of other GhFSN members remain unknown. In this study, roles of GhFSN5 were dissected. qRT-PCR analysis showed that GhFSN5 was predominantly transcribed during the fiber SCW thickening stage. In addition, a large number of fiber SCW biosynthetic genes and SCW-related TFs were co-expressed with GhFSN5. Heterologous expression of GhFSN5 in Arabidopsis resulted in plants with smaller siliques and severe sterility. Anther dehiscence in transgenic lines was not substantially affected, but most pollen was collapsed and nonviable. Furthermore, cellulose and lignin contents in inflorescence stems as well as roots were reduced in transgenic lines, compared with the wild type. Moreover, a set of SCW biosynthetic genes for cellulose, xylan and lignin and several transcription factors involved in regulation of SCW formation were down-regulated in transgenic plants. Our findings indicate that GhFSN5 acts as a negative regulator of SCW formation and anther development and expands our understanding of transcriptional regulation of SCW biosynthesis.

Crustal growth and reworking: A case study from the Erguna Massif, eastern Central Asian Orogenic Belt.

Despite being the largest accretionary orogen on Earth, the record of crustal growth and reworking of individual microcontinental massifs within the Central Asian Orogenic Belt (CAOB) remain poorly constrained. Here, we focus on zircon records from granitoids in the Erguna Massif to discuss its crustal evolution through time. Proterozoic-Mesozoic granitoids are widespread in the Erguna Massif, and spatiotemporal variations in their zircon εHf(t) values and TDM2(Hf) ages reveal the crustal heterogeneity of the massif. Crustal growth curve demonstrates that the initial crust formed in the Mesoarchean, and shows a step-like pattern with three growth periods: 2.9-2.7, 2.1-1.9, and 1.7-0.5 Ga. This suggests that microcontinental massifs in the eastern CAOB have Precambrian basement, contradicting the hypothesis of significant crustal growth during the Phanerozoic. Phases of growth are constrained by multiple tectonic settings related to supercontinent development. Calculated reworked crustal proportions and the reworking curve indicate four reworking periods at 1.86-1.78 Ga, 860-720 Ma, 500-440 Ma, and 300-120 Ma, which limited the growth rate. These periods of reworking account for the crustal heterogeneity of the Erguna Massif.

Genome-Wide Identification of R2R3-MYB Transcription Factors Regulating Secondary Cell Wall Thickening in Cotton Fiber Development.

MYB proteins represent one of the largest transcription factor (TF) families in plants, some of which act as key transcriptional regulators of secondary cell wall (SCW) biosynthesis. Cotton (Gossypium hirsutum) fiber is thought to be an ideal single-cell model to study cell elongation and SCW biosynthesis. However, little knowledge regarding the TFs controlling fiber SCW biosynthesis, particularly for R2R3-MYBs is known. By far, no comprehensive genome-wide analysis of the secondary wall-associated R2R3-MYBs has been reported in cultivated tetraploid upland cotton. In this study, we identified 419 R2R3-MYB genes by systematically examining the cotton genome. A combination of phylogenetic, RNA-seq and co-expression analyses indicated that 36 R2R3-MYBs were either preferentially or highly expressed in 20 day post anthesis (dpa) fibers and are putative SCW regulators. Among these MYB genes, 22 MYBs are homologs of known SCW MYB proteins and the other 14 MYBs are novel proteins without prior reported SCW biosynthesis-related functions. Finally, we highlighted on the roles of two MYBs named GhMYB46_D13 and GhMYB46_D9, both of which displayed the highest expression in 20 dpa fibers. Expression of GhMYB46_D13 or GhMYB46_D9 individually in Arabidopsis resulted in ectopic SCW deposition in transgenic plants. Furthermore, both GhMYB46_D13 and GhMYB46_D9 were able to activate the cotton fiber SCW cellulose synthase gene promoters. Thus, we have identified 36 R2R3-MYBs as potential SCW regulators in cotton fibers that represent strong candidates for further functional studies during fiber development and SCW thickening.

A new C20-diterpenoid alkaloid from Aconitum soongaricum var. pubescens.

A new denudatine-type C20-diterpenoid alkaloid, pubesine (1), along with seven known diterpenoid alkaloids, altaconitine (2), 14-benzoylaconine (3), spicatine A (4), 14-benzoylaconine-8-palmitate (5), 14-O-acetylsenbusine A (6), senbusine A (7) and 14-acetylneoline (8) were isolated from the whole plant of Aconitum soongaricum var. pubescens. Their structures were elucidated by means of extensive spectroscopic analyses (NMR and HR-ESI-MS) and comparison with data reported in the literature. All compounds were evaluated for their cytotoxicity against H460, MCF-7 and Hep G2 human cancer cell lines.

The cotton ß-galactosyltransferase 1 (GalT1) that galactosylates arabinogalactan proteins participates in controlling fiber development.

Arabinogalactan proteins (AGPs) are highly glycosylated proteins that play pivotal roles in diverse developmental processes in plants. Type-II AG glycans, mostly O-linked to the hydroxyproline residues of the protein backbone, account for up to 95% w/w of the AGP, but their functions are still largely unclear. Cotton fibers are extremely elongated single-cell trichomes on the seed epidermis; however, little is known of the molecular basis governing the regulation of fiber cell development. Here, we characterized the role of a CAZy glycosyltransferase 31 (GT31) family member, GhGalT1, in cotton fiber development. The fiber length of the transgenic cotton overexpressing GhGalT1 was shorter than that of the wild type, whereas in the GhGalT1-silenced lines there was a notable increase in fiber length compared with wild type. The carbohydrate moieties of AGPs were altered in fibers of GhGalT1 transgenic cotton. The galactose: arabinose ratio of AG glycans was higher in GhGalT1 overexpression fibers, but was lower in GhGalT1-silenced lines, compared with that in the wild type. Overexpression of GhGalT1 upregulates transcript levels of a broad range of cell wall-related genes, especially the fasciclin-like AGP (FLA) backbone genes. An enzyme activity assay demonstrated that GhGalT1 is a ß-1,3-galactosyltransferase (ß-1,3-GalT) involved in biosynthesis of the ß-1,3-galactan backbone of the type-II AG glycans of AGPs. We also show that GhGalT1 can form homo- and heterodimers with other cotton GT31 family members to facilitate AG glycan assembly of AGPs. Thus, our data demonstrate that GhGalT1 influences cotton fiber development via controlling the glycosylation of AGPs, especially FLAs.

Phosphorylation of serine residue modulates cotton Di19-1 and Di19-2 activities for responding to high salinity stress and abscisic acid signaling.

Di19 (drought-induced protein 19) family is a novel type of Cys2/His2 zinc-finger proteins. In this study, we demonstrated that cotton Di19-1 and Di19-2 (GhDi19-1/-2) proteins could be phosphorylated in vitro by the calcium-dependent protein kinase (CDPK). Mutation of Ser to Ala in N-terminus of GhDi19-1/-2 led to the altered subcellular localization of the two proteins, but the constitutively activated form (Ser was mutated to Asp) of GhDi19-1/-2 still showed the nuclear localization. GhDi19-1/-2 overexpression transgenic Arabidopsis seedlings displayed the hypersensitivity to high salinity and abscisic acid (ABA). However, Ser site-mutated GhDi19-1(S116A) and GhDi19-2(S114A), and Ser and Thr double sites-mutated GhDi19-1(S/T-A/A) and GhDi19-2(S/T-A/A) transgenic Arabidopsis did not show the salt- and ABA-hypersensitive phenotypes. In contrast, overexpression of Thr site-mutated GhDi19-1(T114A) and GhDi19-2(T112A) in Arabidopsis still resulted in salt- and ABA-hypersensitivity phenotypes, like GhDi19-1/-2 transgenic lines. Overexpression of GhDi19-1/-2 and their constitutively activated forms in Atcpk11 background could recover the salt- and ABA-insensitive phenotype of the mutant. Thus, our results demonstrated that Ser phosphorylation (not Thr phosphorylation) is crucial for functionally activating GhDi19-1/-2 in response to salt stress and ABA signaling during early plant development, and GhDi19-1/-2 proteins may be downstream targets of CDPKs in ABA signal pathway.

Cotton GhMYB7 is predominantly expressed in developing fibers and regulates secondary cell wall biosynthesis in transgenic Arabidopsis.

The secondary cell wall in mature cotton fibers contains over 90% cellulose with low quantities of xylan and lignin. However, little is known regarding the regulation of secondary cell wall biosynthesis in cotton fibers. In this study, we characterized an R2R3-MYB transcription factor, GhMYB7, in cotton. GhMYB7 is expressed at a high level in developing fibers and encodes a MYB protein that is targeted to the cell nucleus and has transcriptional activation activity. Ectopic expression of GhMYB7 in Arabidopsis resulted in small, curled, dark green leaves and also led to shorter inflorescence stems. A cross-sectional assay of basal stems revealed that cell wall thickness of vessels and interfascicular fibers was higher in transgenic lines overexpressing GhMYB7 than in the wild type. Constitutive expression of GhMYB7 in Arabidopsis activated the expression of a suite of secondary cell wall biosynthesis-related genes (including some secondary cell wall-associated transcription factors), leading to the ectopic deposition of cellulose and lignin. The ectopic deposition of secondary cell walls may have been initiated before the cessation of cell expansion. Moreover, GhMYB7 was capable of binding to the promoter regions of AtSND1 and AtCesA4, suggesting that GhMYB7 may function upstream of NAC transcription factors. Collectively, these findings suggest that GhMYB7 is a potential transcriptional activator, which may participate in regulating secondary cell wall biosynthesis of cotton fibers.

Diterpenoid Alkaloids from Aconitum soongaricum var. pubescens.

One new diterpenoid alkaloid, pubescensine (1), along with nine known diterpenoid alkaloids (2-10) were isolated from the roots of Aconitum soongaricum var. pubescens. Their structures were elucidated by spectroscopic analyses and comparison with previously reported data. All the compounds were evaluated for their antifeedant activities. The aconitine-type diterpenoid alkaloids (1-6) showed considerably potent antifeedant activity (EC50 < 1 mg/cm2), while the activities of napelline-type diterpenoid alkaloids (compds. 7, 9 and 10) were not significant (EC50 > 50 mg/cm2).

Asymmetric dimethylarginine is associated with carotid atherosclerosis in patients with essential hypertension.

This study was to assess the relationship between asymmetric dimethylarginine (ADMA) and carotid atherosclerosis in patients with essential hypertension. A total of 182 individuals with never-treated essential hypertension and 182 age-matched healthy controls were studied. Plasma ADMA levels, mean intima-media thickness (IMT) and plaque score were significantly greater in hypertensive patients than normotensive controls. ADMA was positively correlated with mean IMT. On multiple logistic regression analysis, ADMA was a crucial independent predictor of carotid plaque formation (plaque score ≥1.1). Our results suggest that increased levels of ADMA are associated with the development of carotid atherosclerosis in hypertensive patients.

Asymmetric dimethylarginine is associated with high-sensitivity C-reactive protein and early carotid atherosclerosis in women with previous gestational diabetes mellitus.

Asymmetric dimethylarginine (ADMA) is increased in subjects with previous gestational diabetes mellitus (GDM). The aim of this study was to investigate the relationship between serum ADMA levels and early carotid atherosclerosis in women with history of GDM. A total of 42 normoglycemic women with previous GDM and 42 age-matched healthy controls were enrolled. Serum levels of ADMA, lipids, insulin, fasting and 2-h glucose following 75-g oral glucose tolerance test, and high sensitivity C-reactive protein (hsCRP) were measured. Carotid atherosclerosis was evaluated by ultrasonographically determined intima-media thickness (IMT). Serum ADMA and hsCRP were higher in women with previous GDM compared to the healthy controls (0.72 ± 0.16 vs. 0.41 ± 0.15 µmol/L, p < 0.001; 1.81 ± 0.32 vs. 1.05 ± 0.26 mg/L, p < 0.001; respectively). Carotid IMT was also increased in the previous GDM group (0.77 ± 0.14 vs. 0.52 ± 0.13 mm, p < 0.001). In women with previous GDM, ADMA was positively correlated with hsCRP (r = 41, p < 0.001) and carotid IMT (r = 0.38, p < 0.001). Multiple linear regression analysis revealed that ADMA was a significant predictor for elevated carotid IMT in subjects with previous GDM after adjusting for traditional risk factors (ß = 0.26, p = 0.017). Our data demonstrated that serum ADMA was associated with hsCRP and carotid IMT in normoglycemic women with previous GDM.

Arabidopsis drought-induced protein Di19-3 participates in plant response to drought and high salinity stresses.

Di19 (drought-induced protein19) family is a novel type of Cys2/His2 zinc-finger proteins. In this study, Arabidopsis Di19-3 was functionally characterized. The experimental results revealed that AtDi19-3 is a transcriptional activator, and could bind to the TACA(A/G)T sequence. AtDi19-3 expression in plants was remarkably induced by NaCl, mannitol and abscisic acid (ABA). T-DNA insertion mutation of AtDi19-3 results in an increase in plant tolerance to drought and high salinity stresses and ABA, whereas overexpression of AtDi19-3 leads to a drought-, salt- and ABA-sensitive phenotype of the transgenic plants. In the presence of NaCl, mannitol or ABA, rates of seed germination and cotyledon greening in Atdi19-3 mutant were higher, but in AtDi19-3 overexpression transgenic plants were lower than those in wild type. Roots of Atdi19-3 mutant seedlings were longer, but those of AtDi19-3 overexpression transgenic seedlings were shorter than those of wild type. Chlorophyll and proline contents in Atdi19-3 mutant were higher, but in AtDi19-3 overexpression seedlings were lower than those in wild type. Atdi19-3 mutant showed greater drought-tolerance, whereas AtDi19-3 overexpression transgenic plants exhibited more drought-sensitivity than wild type. Furthermore, expression of the genes related to ABA signaling pathway was altered in Atdi19-3 mutant and AtDi19-3 transgenic plants. These data suggest that AtDi19-3 may participate in plant response to drought and salt stresses in an ABA-dependent manner.

Two cotton fiber-associated glycosyltransferases, GhGT43A1 and GhGT43C1, function in hemicellulose glucuronoxylan biosynthesis during plant development.

Xylan is the major hemicellulosic constituent in dicot secondary cell walls. Cell wall composition of cotton fiber changes dynamically throughout development. Not only the amounts but also the molecular sizes of the hemicellulosic polysaccharides show substantial changes during cotton fiber development. However, none of the genes encoding glycosyltransferases (GTs) responsible for synthesizing xylan have been isolated and characterized in cotton fiber. In this study, we applied a bioinformatics approach and identified two putative GTs from cotton, designated GhGT43A1 and GhGT43C1, which belong to the CAZy GT43 family and are closely related to Arabidopsis IRX9 and IRX14, respectively. We show that GhGT43A1 is highly and preferentially expressed in 15 and 20 days post-anthesis (dpa) cotton fiber, whereas GhGT43C1 is ubiquitously expressed in most organs, with especially high expression in 15 dpa fiber and hypocotyl. Complementation analysis demonstrates that GhG43A1 and GhGT43C1 are orthologs of Arabidopsis IRX9 and IRX14, respectively. Furthermore, we show that overexpression of GhGT43A1 or GhGT43C1 in Arabidopsis results in increased xylan content. We also show that overexpression of GhGT43A1 or GhGT43C1 leads to more cellulose deposition. These findings suggest that GhGT43A1 and GhGT43C1 likely participate in xylan synthesis during fiber development.