Photosynthetic plasticity aggravates the susceptibility of magnesium-deficient leaf to high light in rapeseed plants: the importance of Rubisco and mesophyll conductance.

Plants grown under low magnesium (Mg) soils are highly susceptible to encountering light intensities that exceed the capacity of photosynthesis (A), leading to a depression of photosynthetic efficiency and eventually to photooxidation (i.e., leaf chlorosis). Yet, it remains unclear which processes play a key role in limiting the photosynthetic energy utilization of Mg-deficient leaves, and whether the plasticity of A in acclimation to irradiance could have cross-talk with Mg, hence accelerating or mitigating the photodamage. We investigated the light acclimation responses of rapeseed (Brassica napus) grown under low- and adequate-Mg conditions. Magnesium deficiency considerably decreased rapeseed growth and leaf A, to a greater extent under high than under low light, which is associated with higher level of superoxide anion radical and more severe leaf chlorosis. This difference was mainly attributable to a greater depression in dark reaction under high light, with a higher Rubisco fallover and a more limited mesophyll conductance to CO2 (gm ). Plants grown under high irradiance enhanced the content and activity of Rubisco and gm to optimally utilize more light energy absorbed. However, Mg deficiency could not fulfill the need to activate the higher level of Rubisco and Rubisco activase in leaves of high-light-grown plants, leading to lower Rubisco activation and carboxylation rate. Additionally, Mg-deficient leaves under high light invested more carbon per leaf area to construct a compact leaf structure with smaller intercellular airspaces, lower surface area of chloroplast exposed to intercellular airspaces, and CO2 diffusion conductance through cytosol. These caused a more severe decrease in within-leaf CO2 diffusion rate and substrate availability. Taken together, plant plasticity helps to improve photosynthetic energy utilization under high light but aggravates the photooxidative damage once the Mg nutrition becomes insufficient.

Sufficient potassium improves inorganic phosphate-limited photosynthesis in Brassica napus by enhancing metabolic phosphorus fractions and Rubisco activity.

Crop photosynthesis (A) and productivity are often limited by a combination of nutrient stresses, such that changes in the availability of one nutrient may affect the availability of another nutrient, in turn influencing A. In this study, we examined the synergistic effects of phosphorus (P) and potassium (K) on leaf A in a nutrient amendment experiment, in which P and K were added individually or in combination to Brassica napus grown under P and K co-limitation. The data revealed that the addition of P gradually removed the dominant limiting factor (i.e. the limited availability of P) and improved leaf A. Strikingly, the addition of K synergistically improved the overall uptake of P, mainly by boosting plant growth, and compensated for the physiological demand for P by prioritizing investment in metabolic pools of P (P-containing metabolites and inorganic phosphate, Pi). The enlarged pool of metabolically active P was partially associated with the upregulation of Pi regeneration through release from triose phosphates rather than replacement of P-containing lipids. This process mitigated P restrictions on A by maintaining the ATP/NADPH and NADPH/NADP+ ratios and increasing the content and activity of Rubisco. Our findings demonstrate that sufficient K increased Pi-limited A by enhancing metabolic P fractions and Rubisco activity. Thus, ionic synergism may be exploited to mitigate nutrient-limiting factors to improve crop productivity.

Potassium deficiency enhances imbalances in rice water relations under water deficit by decreasing leaf hydraulic conductance.

Potassium (K+) is an essential macronutrient for appropriate plant development and physiology. However, little is known about the mechanisms involved in the regulation of leaf water relations by K under water deficit. A pot experiment with two K supplies of 0.45 and 0 g K2O per pot (3 kg soil per pot) and two watering conditions (well-watered and water-deficit) was conducted to explore the effects of K deficiency on canopy transpiration characteristics, leaf water status, photosynthesis, and hydraulic traits in two rice genotypes with contrasting resistance to drought. The results showed that K deficiency reduced canopy transpiration rate by decreasing stomatal conductance, which led to higher canopy temperatures, resulting in limited water deficit tolerance in rice. In addition, K deficiency led to further substantial reductions in leaf relative water content and water potential under water deficit, which increased the imbalance in leaf water relations under water deficit. Notably, K deficiency limited leaf gas exchange by reducing leaf hydraulic conductance, but decreased the intrinsic water use efficiency under water deficit, especially for the drought-resistant cultivar. Further analysis of the underlying process of leaf hydraulic resistance revealed that the key limiting factor of leaf hydraulic conductance under K deficiency was the outside-xylem hydraulic conductance rather than the xylem hydraulic conductance. Overall, our results provide a comprehensive perspective for assessing leaf water relations under K deficiency, water deficit, and their combined stresses, which will be useful for optimal rice fertilization strategies.

VisuMax Flap 2.0: a flap plus technique to reduce incidence of an opaque bubble layer in femtosecond laser-assisted LASIK.

PURPOSE: To evaluate the incidence of an opaque bubble layer (OBL) in femtosecond laser-assisted in situ keratomileusis (FS-LASIK) flaps created with VisuMax Flap 2.0 as a result of a modification in the parameters of the flap programming. METHODS: This retrospective study was comprised of 1400 eyes of 715 patients who received FS-LASIK surgery. OBLs were measured and reported as a percentage of the flap area to identify the incidence and extent. Flap creation, which is a modification technique, was performed with 8.1-mm flap diameters plus 0.3-mm enlarged interlamellar photodisruption (group Flap 2.0). The same flap diameters without extra photodisruption as the previous standard setting were also implemented (group Flap 1.0). The preoperative measurements, including sphere, cylinder, keratometry, and intraoperative characteristics such as flap size and thickness, were documented. Possible risk factors for the occurrence of OBLs were investigated in this study. RESULTS: The incidence of an OBL was reduced when using the Flap 2.0 program (31.4%) compared to the Flap 1.0 program (63.7%). The area of hard and soft OBLs created by the Flap 2.0 program is smaller than those created by the Flap 1.0 program (P = 0.007 and P < 0.001). Multivariate logistic regression indicated that a thinner flap (P = 0.038) and a higher sphere (P = 0.001) affected the chance of hard OBLs occurring. CONCLUSION: The VisuMax Flap 2.0 program promotes gas venting by enlarging the interlamellar photodisruption size. The incidence and extent of OBLs appear to be reduced significantly when the Flap 2.0 program is applied.

Loading test on the oil tank ground settlement performance monitored by an optical parallel scheme.

A loading test of the ground settlement (GS) performance of the oil tank must be examined before beginning its commercial service. This test requires the sensors to be installed around the oil tank, and the GS is measured while water is being filled in, where the liquid level is read with an ultrasonic radar equipment, etc., to indicate the applied water loads. During the service of the oil tank, loading and unloading corresponding to the oil inlet and outlet are the critical factors to cause the oil tank destruction in a fatigue way. Thus, a regular in-service loading test is the means of evaluating the tank base health condition. However, the sensors for GS measurement of the oil tank are mostly based on a liquid hydraulic sensor, which is an intrinsically static sensor determined by the fluidity of the measurement liquid. In order to meet the instantaneous requirement of the loading test, first, the configuration of the optical GS sensor was designed to suit the simultaneous measurement. Secondly, a data acquisition system was designed by combining the digital signal processing with a field programmable gate array to carry out a parallel multiple channel data collection. This ensures that the GS sensors are interrogated simultaneously to snapshot a GS status of the oil tank, even if its load was changed slowly. A practical oil inlet process was recorded with an ultrasonic radar oil level measurement, and the results of oil tank GS were verified with a manual measurement by using the Electronic Total Station. The effectiveness of our sensor monitoring of the oil tank GS performance during the loading test has been proven.

Effects of optimized nitrogen fertilizer management on the yield, nitrogen uptake, and ammonia volatilization of direct-seeded rice.

BACKGROUND: Direct-seeded rice has been developed rapidly because of labor savings. Changes in rice cultivation methods put forward new requirements for nitrogen (N) fertilizer management practices. Field experiments with five different fertilizer ratios of basal, tillering and panicle fertilizer, namely N1 (10:0:0), N2 (6:2:2), N3 (4:3:3), N4 (2:4:4) and N5 (0:5:5), were conducted to investigate the effects of different N fertilizer management practices on yield formation, N uptakes, and ammonia (NH3 ) volatilization from paddy fields in direct-seeded rice. RESULTS: The results showed that the N4 treatment improved grain yield by 5.1% while decreasing NH3 volatilization by 20.4% compared with that of conventional fertilizer treatment (N2). The panicle number per unit area was the key factor to determine the yield of direct-seeded rice (72%). Excessive N application of basal fertilizer (N1) reduced seedling emergence, N use efficiency, and yield by 45.3%, 160.6%, and 6.9% respectively and increased NH3 volatilization by 28.1% compared with that of the N4 treatment. Removal of basal N fertilizer (N5) N reduced spike number and yield by 13.0% and 6.9% respectively, minimizing NH3 volatilization while affecting the construction of high-yielding populations compared with that of the N4 treatment. CONCLUSION: Optimized N fertilizer management achieved delayed senescence (maintenance of higher leaf Soil Plant Analysis Development meter values in late reproduction), higher canopy photoassimilation (suitable leaf area), higher N fertilizer use efficiency, and less N loss (lower cumulative NH3 volatilization). © 2023 Society of Chemical Industry.

Potassium availability influences the mesophyll structure to coordinate the conductance of CO2 and H2 O during leaf expansion.

Leaf growth relies on photosynthesis and hydraulics to provide carbohydrates and expansion power; in turn, leaves intercept light and construct organism systems for functioning. Under potassium (K) deficiency stress, leaf area, photosynthesis and hydraulics are all affected by alterations in leaf structure. However, the connection between changes in leaf growth and function caused by the structure under K regulation is unclear. Consequently, the leaf hydraulic conductance (Kleaf ) and photosynthetic rate (A) combined with leaf anatomical characteristics of Brassica napus were continuously observed during leaf growth under different K supply levels. The results showed that Kleaf and A decreased simultaneously after leaf area with the increasing K deficiency stress. K deficiency significantly increased longitudinal mesophyll cell investment, leading to a reduced volume fraction of intercellular air-space (fias ) and decreased leaf expansion rate. Furthermore, reduced fias decreased mesophyll and chloroplast surfaces exposed to intercellular airspace and gas phase H2 O transport, which induced coordinated changes in CO2 mesophyll conductance and hydraulic conductance in extra-xylem pathways. Adequate K supply facilitated higher fias through smaller palisade tissue cell density (loose mesophyll cell arrangement) and smaller spongy tissue cell size, which coordinated CO2 and H2 O conductance and promoted leaf area expansion.

Potassium regulates diel leaf growth of Brassica napus by coordinating the rhythmic carbon supply and water balance.

Carbon and water are two main factors limiting leaf expansion. Restriction of leaf growth by low availability of carbon or water is among the earliest visible effects of potassium (K) deficiency. It is not known how K is involved in regulating the rhythmic supply of these two substrates, which differ remarkably across the day-night cycle, affecting leaf expansion. We investigated the effects of different K regimes on the time courses of leaf expansion, carbon assimilation, carbohydrates, and hydraulic properties of Brassica napus. Potassium supply increased leaf area, predominantly by promoting night-time leaf expansion (>60%), which was mainly associated with increased availability of carbohydrates from photosynthetic carbon fixation and import from old leaves rather than improvement of leaf hydraulics. However, sufficient K improved leaf hydraulic conductance to balance diurnal evaporative water loss and increase the osmotic contribution of water-soluble carbohydrates, thereby maintaining leaf turgor and increasing the daytime expansion rate. The results also indicated an ontogenetic role of K in modifying the amplitude of circadian expansion; almost 80% of the increase in leaf area occurred before the area reached 66.9% of the mature size. Our data provide mechanistic insight into K-mediated diel coordination of rhythmic carbon supply and water balance in leaf expansion.

Access to gem-Difluoroalkenes via Organic Photoredox-Catalyzed gem-Difluoroallylation of Alkyl Iodides.

An organic photoredox-catalyzed gem-difluoroallylation of α-trifluoromethyl alkenes with alkyl iodides via C-F bond cleavage for the synthesis of gem-difluoroalkene derivatives is reported. This transition-metal-free transformation utilized a readily available organic dye 4CzIPN as the sole photocatalyst and employed a common chemical N,N,N',N'-tetramethylethylenediamine as the radical activator of alkyl iodides via halogen-atom transfer. In addition, a variety of iodides, including primary, secondary, and tertiary alkyl iodides, were tolerated and provided good to high yields.

The Long Noncoding RNA RP11-728F11.4 Promotes Atherosclerosis.

OBJECTIVE: Noncoding RNAs are emerging as important players in gene regulation and cardiovascular diseases. Their roles in the pathogenesis of atherosclerosis are not fully understood. The purpose of this study was to determine the role played by a previously uncharacterized long noncoding RNA, RP11-728F11.4, in the development of atherosclerosis and the mechanisms by which it acts. Approach and Results: Expression microarray analysis revealed that atherosclerotic plaques had increased expression of RP11-728F11.4 as well as the cognate gene FXYD6 (FXYD domain containing ion transport regulator 6), which encodes a modulator of Na+/K+-ATPase. In vitro experiments showed that RP11-728F11.4 interacted with the RNA-binding protein EWSR1 (Ewings sarcoma RNA binding protein-1) and upregulated FXYD6 expression. Lentivirus-induced overexpression of RP11-728F11.4 in cultured monocytes-derived macrophages resulted in higher Na+/K+-ATPase activity, intracellular cholesterol accumulation, and increased proinflammatory cytokine production. The effects of RP11-728F11.4 were enhanced by siRNA-mediated knockdown of EWSR1 and reduced by downregulation of FXYD domain containing ion transport regulator 6. In vivo experiments in apoE knockout mice fed a Western diet demonstrated that RP11-728F11.4 increased proinflammatory cytokine production and augmented atherosclerotic lesions. CONCLUSIONS: RP11-728F11.4 promotes atherosclerosis, with an influence on cholesterol homeostasis and proinflammatory molecule production, thus representing a potential therapeutic target. Graphic Abstract: A graphic abstract is available for this article.

Rapid soil rewetting promotes limited N2O emissions and suppresses NH3 volatilization under urea addition.

The alternation of dry and wet is an important environmental factor affecting the emission of nitrous oxide from soil. However, the consistent or opposite effects on NH3 and N2O emissions caused by adding exogenous urea in this process have not been fully considered. Here, we controlled the initial (slow drying) and final (adding water) water-filled pore space (WFPS) at 70%, 60%, or 50% through microculture experiment to simulate a process of slow drying-fertilization and rapid wetting of the soil from rice harvest to dryland crop fertilization. Through measuring soil chemical properties and the abundance and composition of related microbial communities during drying process, we studied the pathways of influence of drying and rewetting on the emission of N2O and NH3 after urea application. During the progressive drying process (WFPS decreasing from 70% to 60% and 50%), soil N2O and NH3 emissions decreased by 49.77%-72.13% and 17.89%-42.19%, respectively. After rapid rewetting (WFPS increasing from 60% to 70%, 50%-60% and 70%), N2O emissions showed a slight increase, while NH3 volatilization continued to decrease. Soil NH4+-N and DOC contents both decreased during progressive drying, while the soil NO3--N content was enhanced. The drying process changed the community structure of ureC and amoA-b and reduced their abundance but had no effect on amoA-a, nirK or nirS. Correlation analysis indicated that the reductions in NH4+-N content and the abundances of ureC and amoA-b were the main factors suppressing N2O and NH3 emissions. We believe that drying process limits the related microbial activity and substrate supply during ammonia oxidation process in terms of N2O emissions, while in terms of NH3 volatilization, it reduces the related microbial activity of urea hydrolysis process and increases the ammonium adsorption to the soil.

Straw incorporation improved the adsorption of potassium by increasing the soil humic acid in macroaggregates.

Straw incorporation has been broadly demonstrated to be effective for the maintenance of soil potassium (K) fertility in farmlands, which increases K and carbon (C) inputs and improves soil stability due to aggregate formation and physiochemical bonding. However, the response of K retention in aggregate fractions (AFs) to soil organic carbon (SOC) changes is poorly understood. Field trials under a completely random experimental design considering two factors, straw return and K fertilization, were conducted to study the comprehensive effects of SOC and various AFs on soil K adsorption. The results indicated that the soil exchangeable and nonexchangeable K pools (EKP and NKP) increased upon straw incorporation due to an increase in macroaggregates (>2 mm fraction). The synergistic increase in SOC and humic acid (HA) contents, which resulted in a complex molecular structure and improved soil aggregation, promoted K adsorption. Good linear relationships existed between the apparent K balance and the EKP and NKP values in the >2 mm fraction. Structural equation modeling (SEM) indicated that SOC and various AFs exerted positive and significant effects on soil EKP and NKP, and thus verified 96% of the total variation in K adsorption. Thus, combination of straw and K fertilization increased the aggregate-associated C and K, which were primarily correlated with the >2 mm fraction. These direct measurements and estimates provide insights into the aggregates associated with K, which enhances the understanding of the chemical behavior of soil K upon straw incorporation.

Anatomically induced changes in rice leaf mesophyll conductance explain the variation in photosynthetic nitrogen use efficiency under contrasting nitrogen supply.

BACKGROUND: The ratio of CO2 mesophyll conductance (gm) to Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) content has been suggested to positively affect photosynthetic nitrogen use efficiency (PNUE). The anatomical basis of gm has been quantified, but information on the relationship between cell-level anatomies and PNUE is less advanced. Here, hydroponic experiments were conducted in rice plants supplied with ammonium (NH4+) and nitrate (NO3-) under three N levels (low, 0.71 mM; intermediate, 2.86 mM; high, 7.14 mM) to investigate the gas exchange parameters, leaf anatomical structure and PNUE. RESULTS: The results showed a lower PNUE in plants supplied with high nitrogen and NH4+, which was positively correlated with the gm/Rubisco ratio. A one-dimensional within-leaf model revealed that the resistance to CO2 diffusion in the liquid phase (rliq) dominated the overall mesophyll resistance (rm), in which CO2 transfer resistance in the cell wall, cytoplasm and stroma were significantly affected by nitrogen supply. The chloroplast surface area exposed to intercellular space (Sc) per Rubisco rather than the gm/Sc ratio was positively correlated with PNUE and was thus considered a key component influencing PNUE. CONCLUSION: In conclusion, our study emphasized that Sc was the most important anatomical trait in coordinating gm and PNUE with contrasting N supply.

The reduction in leaf area precedes that in photosynthesis under potassium deficiency: the importance of leaf anatomy.

Synergistic improvement in leaf photosynthetic area and rate is essential for enhancing crop yield. However, reduction in leaf area occurs earlier than that in the photosynthetic rate under potassium (K) deficiency stress. The photosynthetic capacity and anatomical characteristics of oilseed rape (Brassica napus) leaves in different growth stages under different K levels were observed to clarify the mechanism regulating this process. Increased mesophyll cell size and palisade tissue thickness, in K-deficient leaves triggered significant enlargement of mesophyll cell area per transverse section width (S/W), in turn inhibiting leaf expansion. However, there was only a minor difference in chloroplast morphology, likely because of K redistribution from vacuole to chloroplast. As K stress increased, decreased mesophyll surface exposed to intercellular space and chloroplast density induced longer distances between neighbouring chloroplasts (Dchl-chl ) and decreased the chloroplast surface area exposed to intercellular space (Sc /S); conversely this induced a greater limitation imposed by the cytosol on CO2 transport, further reducing the photosynthetic rate. Changes in S/W associated with mesophyll cell morphology occurred earlier than changes in Sc /S and Dchl-chl , inducing a decrease in leaf area before photosynthetic rate reduction. Adequate K nutrition simultaneously increases photosynthetic area and rate, thus enhancing crop yield.

Nutrition-mediated cell and tissue-level anatomy triggers the covariation of leaf photosynthesis and leaf mass per area.

Plants in nutrient-poor habitats converge towards lower rates of leaf net CO2 assimilation (Aarea); however, they display variability in leaf mass investment per area (LMA). How a plant optimizes its leaf internal carbon investment may have knock-on effects on structural traits and, in turn, affect leaf carbon fixation. Quantitative models were applied to evaluate the structural causes of variations in LMA and their relevance to Aarea in rapeseed (Brassica napus) based on their responses to nitrogen (N), phosphorus (P), potassium (K), and boron (B) deficiencies. Leaf carbon fixation decreased in response to nutrient deficiency, but the photosynthetic limitations varied greatly depending on the deficient nutrient. In comparison with Aarea, the LMA exhibited diverse responses, being increased under P or B deficiency, decreased under K deficiency, and unaffected under N deficiency. These variations were due to changes in cell- and tissue-level carbon investments between cell dry mass density (N or K deficiency) and cellular anatomy, including cell dimension and number (P deficiency), or both (B deficiency). However, there was a conserved pattern independent of nutrient-specific limitations-low nutrient availability reduced leaf carbon fixation but increased carbon investment in non-photosynthetic structures, resulting in larger but fewer mesophyll cells with a thicker cell wall but a lower chloroplast surface area appressed to the intercellular airspace, which reduced the mesophyll conductance and feedback-limited Aarea. Our results provide insight into the importance of mineral nutrients in balancing the leaf carbon economy by coordinating leaf carbon assimilation and internal distribution.

An Anisotropic Hydrogel Based on Mussel-Inspired Conductive Ferrofluid Composed of Electromagnetic Nanohybrids.

Anisotropic hydrogels with a hierarchical structure can mimic biological tissues, such as neurons or muscles that show directional functions, which are important factors for signal transduction and cell guidance. Here, we report a mussel-inspired approach to fabricate an anisotropic hydrogel based on a conductive ferrofluid. First, polydopamine (PDA) was used to mediate the formation of PDA-chelated carbon nanotube-Fe3O4 (PFeCNT) nanohybrids and also used as a dispersion medium to stabilize the nanohybrids to form a conductive ferrofluid. The ferrofluid can respond to an orientated magnetic field and be programed to form aligned structures, which were then frozen in a hydrogel network formed via in situ free-radical polymerization and gelation. The resulted hydrogel shows directional conductive and mechanical properties, mimicking an oriented biological tissue. Under external electrical stimulation, the orientated PFeCNT nanohybrids can be sensed by the myoblasts cultured on the hydrogel, resulting in the oriented growth of cells. In summary, the mussel-inspired anisotropic hydrogel with its aligned structural complexity and anisotropic properties together with the cell affinity and tissue adhesiveness is a potent multifunctional biomaterial for mimicking oriented tissues to guide cell proliferation and tissue regeneration.

Microarray profiling analysis and validation of novel long noncoding RNAs and mRNAs as potential biomarkers and their functions in atherosclerosis.

Long noncoding (lnc)RNAs have been implicated in the development and progression of atherosclerosis. However, the expression and mechanism of action of lncRNAs in atherosclerosis are still unclear. We implemented microarray analysis in human advanced atherosclerotic plaques and normal arterial intimae to detect the lncRNA and mRNA expression profile. Gene Ontology functional enrichment and pathway analyses were applied to explore the potential functions and pathways involved in the pathogenesis of atherosclerosis. A total of 236 lncRNAs and 488 mRNAs were selected for further Ingenuity Pathway Analysis. Moreover, quantitative RT-PCR tests of most selected lncRNAs and mRNAs with high fold changes were consistent with the microarray data. We also performed ELISA to investigate the corresponding proteins levels of selected genes and showed that serum levels of SPP1, CD36, ATP6V0D2, CHI3L1, MYH11, and BDNF were differentially expressed in patients with coronary heart disease compared with healthy subjects. These proteins correlated with some biochemical parameters used in the diagnosis of cardiovascular diseases. Furthermore, receiver operating characteristic analysis showed a favorable diagnostic performance. The microarray profiling analysis and validation of differentially-expressed lncRNAs and mRNAs in atherosclerosis not only provide new insights into the pathogenesis of this disease but may also reveal new biomarkers for its diagnosis and treatment.

LncRNA AC096664.3/PPAR-γ/ABCG1-dependent signal transduction pathway contributes to the regulation of cholesterol homeostasis.

Atherosclerosis is a complex inflammatory disease that involves disrupted cellular cholesterol levels and formation of foam cells. Studies about long noncoding RNA (lncRNA) have revealed its function in the development of atherosclerosis, by mediating reverse cholesterol transport and formation of foam cells. In this study, we found that oxidized low-density lipoprotein (ox-LDL) markedly decreased lncRNA AC096664.3 in vascular smooth muscle cells (VSMCs) and THP-1 macrophages. We also found that ox-LDL reduced ATP-binding cassette (ABC) G1 through inhibiting lncRNA AC096664.3 in VSMCs. Further experiments showed that the downregulation of lncRNA AC096664.3 reduced ABCG1 expression through inhibiting the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) and that ox-LDL reduced ABCG1 expression through inhibiting the expression of PPAR-γ. Furthermore, we discovered that ox-LDL inhibited ABCG1 via the lncRNA AC096664.3/PPAR-γ/ABCG1 pathway, which led to an increase in total and free cholesterol in VMSCs. Thus, we confirmed that ox-LDL induces cholesterol accumulation via the lncRNA AC096664.3/PPAR-γ/ABCG1 pathway in VSMCs, indicating a promising novel therapy in protecting against atherosclerosis.

Potassium mediates coordination of leaf photosynthesis and hydraulic conductance by modifications of leaf anatomy.

Typical symptoms of potassium deficiency, characterized as chlorosis or withered necrosis, occur concomitantly with downregulated photosynthesis and impaired leaf water transport. However, the prominent limitations and mechanisms underlying the concerted decreases of leaf photosynthesis and hydraulic conductance are poorly understood. Monocots and dicots were investigated based on responses of photosynthesis and hydraulic conductance and their components and the correlated anatomical determinants to potassium deficiency. We found a conserved pattern in which leaf photosynthesis and hydraulic conductance concurrently decreased under potassium starvation. However, monocots and dicots showed two different hydraulic-redesign strategies: Dicots tended to show a decreased minor vein density, whereas monocots reduced the size of the bundle sheath and its extensions, rather than the minor vein density; both of these strategies may restrain xylem and outside-xylem hydraulic conductance. Additionally, potassium-deprived leaves developed with fewer mesophyll cell-to-cell connections, leading to a reduced area being available for liquid-phase flow. Further quantitative analysis revealed that mesophyll conductance to CO2 and outside-xylem hydraulic resistance were the major contributors to photosynthetic limitation and increased hydraulic resistance, at more than 50% and 60%, respectively. These results emphasize the importance of potassium in the coordinated regulation of leaf photosynthesis and hydraulic conductance through modifications of leaf anatomy.

Potassium deficiency aggravates yield loss in rice by restricting the translocation of non-structural carbohydrates under Sarocladium oryzae infection condition.

Sheath rot disease (ShR) caused by Sarocladium oryzae (S. oryzae) infection is an emerging disease that causes severe yield loss by restricting the translocation of non-structural carbohydrates (NSC). Potassium (K) nutrition plays a critical role in disease resistance and the exportation of NSC. However, the physiological mechanisms of K with respect to ShR have not been thoroughly elucidated to date. The objectives of this study were to reveal the mechanisms by which K increases ShR resistance by regulating NSC translocation of rice, therefore, a field experiment combined with an inoculation experiment was conducted. We demonstrate that ShR disease incidence and disease index decreased dramatically with an increasing K application. K deficiency sharply induced the accumulation of NSC in the flag leaf (FL) and flag leaf sheath (FLS) under S. oryzae infection condition, which reduced the contribution of transferred NSC to final yield. A permutational multivariate analysis showed that K deficiency had a greater (49.0%, P < 0.001) effect on the NSC content variation in FL than that of S. oryzae infection (15.0%, P < 0.001). S. oryzae infection dramatically increased the difference in apparent transferred mass of NSC and cell membrane injury of diseased organs between K-deficient and K-sufficient rice. Finally, we demonstrate that cell membrane injury was a limiting factor imposed by K deficiency, which restricts the export of NSC from source organs. This work highlights the importance of K in improving ShR resistance by regulating NSC translocation (particularly the stem NSC).