Photosynthesis Pathways Research Articles

Mapping the global distribution of C4 vegetation using observations and optimality theory

Plants with the C4 photosynthesis pathway typically respond to climate change differently from more common C3-type plants, due to their distinct anatomical and biochemical characteristics. These different responses are expected to drive changes in global C4 and C3 vegetation distributions. However, current C4 vegetation distribution models may not predict this response as they do not capture multiple interacting factors and often lack observational constraints. Here, we used global observations of plant photosynthetic pathways, satellite remote sensing, and photosynthetic optimality theory to produce an observation-constrained global map of C4 vegetation. We find that global C4 vegetation coverage decreased from 17.7% to 17.1% of the land surface during 2001 to 2019. This was the net result of a reduction in C4 natural grass cover due to elevated CO2 favoring C3-type photosynthesis, and an increase in C4 crop cover, mainly from corn (maize) expansion. Using an emergent constraint approach, we estimated that C4 vegetation contributed 19.5% of global photosynthetic carbon assimilation, a value within the range of previous estimates (18–23%) but higher than the ensemble mean of dynamic global vegetation models (14 ± 13%; mean ± one standard deviation). Our study sheds insight on the critical and underappreciated role of C4 plants in the contemporary global carbon cycle.

Natural genetic variation in GLK1-mediated photosynthetic acclimation in response to light

BackgroundGOLDEN-like (GLK) transcription factors are central regulators of chloroplast biogenesis in Arabidopsis and other species. Findings from Arabidopsis show that these factors also contribute to photosynthetic acclimation, e.g. to variation in light intensity, and are controlled by retrograde signals emanating from the chloroplast. However, the natural variation of GLK1-centered gene-regulatory networks in Arabidopsis is largely unexplored.ResultsBy evaluating the activities of GLK1 target genes and GLK1 itself in vegetative leaves of natural Arabidopsis accessions grown under standard conditions, we uncovered variation in the activity of GLK1 centered regulatory networks. This is linked with the ecogeographic origin of the accessions, and can be associated with a complex genetic variation across loci acting in different functional pathways, including photosynthesis, ROS and brassinosteroid pathways. Our results identify candidate upstream regulators that contribute to a basal level of GLK1 activity in rosette leaves, which can then impact the capacity to acclimate to different environmental conditions. Indeed, accessions with higher GLK1 activity, arising from habitats with a high monthly variation in solar radiation levels, may show lower levels of photoinhibition at higher light intensities.ConclusionsOur results provide evidence for natural variation in GLK1 regulatory activities in vegetative leaves. This variation is associated with ecogeographic origin and can contribute to acclimation to high light conditions.

Differential protein analysis of saline-alkali promoting the oil accumulation in Nitzschia palea

BackgroundThe increasingly severe salinization of the aquatic environment has led to serious damage to the habitats of aquatic organisms. Benthic diatoms are commonly employed as indicator species for assessing water quality and serve as a reflection of the overall health of the aquatic ecosystem. Nitzschia palea is a common diatom found in freshwater, with high oil content, rapid reproductive rate, and it is a commonly dominant species in various rivers.ResultsThe results showed that after 4 days (d) of saline-alkali stress, the cell density and chlorophyll a content of Nitzschia palea reached their maximum values. Therefore, we selected Nitzschia palea under 4 d stress for Tandem Mass Tag (TMT) quantitative proteomic analysis to explore the molecular adaptation mechanism of freshwater diatoms under saline-alkali stress. Totally, 854 proteins were enriched, of which 439 differentially expressed proteins were identified. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and subcellular fractionation analysis revealed that these proteins were mainly enriched in the photosynthesis pathway, citric acid cycle (TCA cycle), fatty acid synthesis, and glutathione cycle.ConclusionsThis study aims to reveal the physiological, biochemical and proteomic mechanisms of salt and alkali tolerance and molecular adaptation of Nitzschia palea under different saline-alkali concentrations. This study showed that Nitzschia palea is one candidate of the environmental friendly, renewable bioenergy microalgae. Meantime, Nitzschiapalea reveals for the proteome of the freshwater and provides the basis, it became a model algal species for freshwater diatoms.

Part 2: aspects of the relation between photosynthesis and crop productivity

ABSTRACT Photosynthesis is amongst the basic physiological processes, affecting plants productivity. There can be different means to increase productivity, and most of them involve increase of photosynthetic activity. Photosynthesis can be influenced by many stressors, which exert different effects, but they have in common a negative impact on productivity. Moreover, the alleviation of stress by plants correspondingly decreases productivity. Thus, the summarised effects of stress were only generally mentioned in this article, and the process of photorespiration was underlined. Photorespiratory pathway relates photosynthesis and productivity, and can also protect plants from oxidative stress at the expense of carboxylation. In addition, alterations of the photorespiration can disrupt the balance between carbon and nitrogen in the biomass of plant. Being a common metabolic pathway between the photosynthesis and many assimilatory metabolic pathways, such as the biosynthesis of proteins and assimilaiton of nitrogen and sulphur, photorespiration binds the photosynthesis to productivity. One very important topic, especially under the global increase of CO2 content in the atmosphere is the relation between carbohydrates and protein biosynthesis. It affects differently the C3 and C4 species, thus photosynthetic specifics of these plants were reviewed as well. C4 are often considered more competitive and productive, as compared with other plants and therefore are preferred as innovative crops under the future climatic conditions.

Characterization and analysis of multi-organ full-length transcriptomes in Sphaeropteris brunoniana and Alsophila latebrosa highlight secondary metabolism and chloroplast RNA editing pattern of tree ferns

BackgroundSphaeropteris brunoniana and Alsophila latebrosa are both old relict and rare tree ferns, which have experienced the constant changes of climate and environment. However, little is known about their high-quality genetic information and related research on environmental adaptation mechanisms of them. In this study, combined with PacBio and Illumina platforms, transcriptomic analysis was conducted on the roots, rachis, and pinna of S. brunoniana and A. latebrosa to identify genes and pathways involved in environmental adaptation. Additionally, based on the transcriptomic data of tree ferns, chloroplast genes were mined to analyze their gene expression levels and RNA editing events.ResultsIn the study, we obtained 11,625, 14,391 and 10,099 unigenes of S. brunoniana root, rachis, and pinna, respectively. Similarly, a total of 13,028, 11,431 and 12,144 unigenes were obtained of A. latebrosa root, rachis, and pinna, respectively. According to the enrichment results of differentially expressed genes, a large number of differentially expressed genes were enriched in photosynthesis and secondary metabolic pathways of S. brunoniana and A. latebrosa. Based on gene annotation results and phenylpropanoid synthesis pathways, two lignin synthesis pathways (H-lignin and G-lignin) were characterized of S. brunoniana. Among secondary metabolic pathways of A. latebrosa, three types of WRKY transcription factors were identified. Additionally, based on transcriptome data obtained in this study, reported transcriptome data, and laboratory available transcriptome data, positive selection sites were identified from 18 chloroplast protein-coding genes of four tree ferns. Among them, RNA editing was found in positive selection sites of four tree ferns. RNA editing affected the protein secondary structure of the rbcL gene. Furthermore, the expression level of chloroplast genes indicated high expression of genes related to the chloroplast photosynthetic system in all four species.ConclusionsOverall, this work provides a comprehensive transcriptome resource of S. brunoniana and A. latebrosa, laying the foundation for future tree fern research.

The end game(s) of photosynthetic carbon metabolism.

The year 2024 marks 70 years since the general outline of the carbon pathway in photosynthesis was published. Although several alternative pathways are now known, it is remarkable how many organisms use the reaction sequence described 70 yrs ago, which is now known as the Calvin-Benson cycle or variants such as the Calvin-Benson-Bassham cycle or Benson-Calvin cycle. However, once the carbon has entered the Calvin-Benson cycle and is converted to a 3-carbon sugar, it has many potential fates. This review will examine the last stages of photosynthetic metabolism in leaves. In land plants, this process mostly involves the production of sucrose provided by an endosymbiont (the chloroplast) to its host for use and transport to the rest of the plant. Photosynthetic metabolism also usually involves the synthesis of starch, which helps maintain respiration in the dark and enables the symbiont to supply sugars during both the day and night. Other end products made in the chloroplast are closely tied to photosynthetic CO2 assimilation. These include serine from photorespiration and various amino acids, fatty acids, isoprenoids, and shikimate pathway products. I also describe 2 pathways that can short circuit parts of the Calvin-Benson cycle. These final processes of photosynthetic metabolism play many important roles in plants.

Fine-tuning RNA extraction protocols for polysaccharide-rich freshwater red algae (Rhodophyta).

Freshwater red algae are important primary producers, widely distributed, contributing significantly to nutrient cycling in aquatic ecosystems. Recent studies have focused on identifying the effect of different environmental conditions such as light on the gene expression in photosynthesis pathways. However, obtaining the necessary RNA quantity and quality for sequencing from these algae has been challenging. Although RNA extractions have been optimized for model organisms, RNA extraction for non-model organisms, such as gelatinous (polysaccharide-rich) red algae, requires considerable troubleshooting. The common freshwater red alga, Batrachospermum gelatinosum , was used to test protocols. The extraction efficiency of various sample disruption methods in combination with seven RNA extraction kits was compared. Using a 2-minute disruption procedure with a modification of TRIzol ™ Plus RNA Purification Kit (PureLink ™ RNA Mini Kit + Trizol ™ ) protocol resulted in significantly higher RIN scores (p < 0.05) and high RNA concentration, compared to other methods. The fine-tuned protocol yielded quality RNA (RIN>7) in high concentrations for subsequent sequencing.

Elucidating the regulatory role of long non-coding RNAs in drought stress response during seed germination in leaf mustard.

Leaf mustard (Brassica juncea L. Czern & Coss), an important vegetable crop, experiences pronounced adversity due to seasonal drought stress, particularly at the seed germination stage. Although there is partial comprehension of drought-responsive genes, the role of long non-coding RNAs (lncRNAs) in adjusting mustard's drought stress response is largely unexplored. In this study, we showed that the drought-tolerant cultivar 'Weiliang' manifested a markedly lower base water potential (-1.073MPa vs -0.437 MPa) and higher germination percentage (41.2% vs 0%) than the drought-susceptible cultivar 'Shuidong' under drought conditions. High throughput RNA sequencing techniques revealed a significant repertoire of lncRNAs from both cultivars during germination under drought stress, resulting in the identification of 2,087 differentially expressed lncRNAs (DELs) and their correspondingly linked 12,433 target genes. It was noted that 84 genes targeted by DEL exhibited enrichment in the photosynthesis pathway. Gene network construction showed that MSTRG.150397, a regulatory lncRNA, was inferred to potentially modulate key photosynthetic genes (Psb27, PetC, PetH, and PsbW), whilst MSTRG.107159 was indicated as an inhibitory regulator of six drought-responsive PIP genes. Further, weighted gene co-expression network analysis (WGCNA) corroborated the involvement of light intensity and stress response genes targeted by the identified DELs. The precision and regulatory impact of lncRNA were verified through qPCR. This study extends our knowledge of the regulatory mechanisms governing drought stress responses in mustard, which will help strategies to augment drought tolerance in this crop.

Physiological and transcriptomic analysis provides novel insight into growth in Kam sweet rice under different nitrogen supplies

AbstractKam Sweet Rice (KSR) is a rice cultivar cultivated for thousands of years in China. Proper and balanced use of nitrogen sources is essential for achieving optimal growth and yield in KSR. This study was carried out to find the most effective hydroponic nutrient solution for cultivating and promoting the growth of KSR. Different nitrogen treatments were applied to KSR cultivars GouDan (GD), GouHa (GH), HongHe (HH), LeiLongGang (LG), and ZaiBianXiaoXiangHe (ZH), resulting in noticeable changes in both growth and physiological traits. Our findings revealed that D3 treatment [1.2 mM NH4Cl + 2.4 mM NaNO3+ neutral amino acids (0.1 mM Ser + 0.2 mM Thr + 0.2 mM Gly + 0.2 mM Pro +0.3 mM Ala)] had a notable positive impact on the growth of GH and ZH which showed the best performance in terms of plant height, root length and fresh weight when compared to the control (CK). Through transcriptome analysis, we discovered that these treatments altered the expression levels of genes associated with carbon metabolism, photosynthesis, and nitrogen pathways within 40 days. Interestingly, by altering the growth and tillering in rice transgenic plants, we validated the role of amino acid transporter OsAAP13 identified in transcriptome profiling, underscoring its significance. Our results are helpful for large‐scale production of KSR with the key methods for controlling the growth of KSR. It is a valuable asset for future investigations aimed at unravelling the intricate mechanisms governing plant growth in the context of different nitrogen supplies.

Integrated transcriptome and metabolome analysis of salinity tolerance in response to foliar application of choline chloride in rice (Oryza sativa L.).

Salt stress is a major abiotic stress that affects crop growth and productivity. Choline Chloride (CC) has been shown to enhance salt tolerance in various crops, but the underlying molecular mechanisms in rice remain unclear. To investigate the regulatory mechanism of CC-mediated salt tolerance in rice, we conducted morpho-physiological, metabolomic, and transcriptomic analyses on two rice varieties (WSY, salt-tolerant, and HHZ, salt-sensitive) treated with 500 mg·L-1 CC under 0.3% NaCl stress. Our results showed that foliar application of CC improved morpho-physiological parameters such as root traits, seedling height, seedling strength index, seedling fullness, leaf area, photosynthetic parameters, photosynthetic pigments, starch, and fructose content under salt stress, while decreasing soluble sugar, sucrose, and sucrose phosphate synthase levels. Transcriptomic analysis revealed that CC regulation combined with salt treatment induced changes in the expression of genes related to starch and sucrose metabolism, the citric acid cycle, carbon sequestration in photosynthetic organs, carbon metabolism, and photosynthetic antenna proteins in both rice varieties. Metabolomic analysis further supported these findings, indicating that photosynthesis, carbon metabolism, and carbon fixation pathways were crucial in CC-mediated salt tolerance. The combined transcriptomic and metabolomic data suggest that CC treatment enhances rice salt tolerance by activating distinct transcriptional cascades and phytohormone signaling, along with multiple antioxidants and unique metabolic pathways. These findings provide a basis for further understanding the mechanisms of metabolite synthesis and gene regulation induced by CC in rice in response to salt stress, and may inform strategies for improving crop resilience to salt stress.

Functional identification of Medicago truncatulaMtRAV1 in regulating growth and development1

Related to ABI3 and VP1 (RAV) transcription factors belong to the AP2 and B3 superfamily. RAVs genes have been reported to be involved in plant growth and development regulation. This study screened three RAV genes from Medicago truncatula and named one of them MtRAV1. The MtRAV1 overexpressing plants exhibits traits such as plant dwarfing, delayed flowering, reduced leaf and floral organs, increased branching, and reduced pods and seeds. Gene expression analysis results showed that overexpression of MtRAV1 inhibited the expression of Flowering Locus T (MtFTa1), Suppressor of Overexpression of CO 1 (MtSOC1), GA3-oxidase1 (MtGA3OX1), DWARF14 (MtD14) and Carotenoid Cleavage Dioxygenase 7 (MtCCD7). To further investigate the regulation pathway involved by MtRAV1, RNA-sequencing (RNA-seq) and DNA affinity purification sequencing (DAP-seq) analysis were conducted. RNA-seq results indicated that MtRAV1 might affect plant growth and development by regulating some genes in photosynthesis, circadian rhythm and plant hormone signaling pathways, especially the auxin signaling pathway. Conjoint analysis of DAP-seq and RNA-seq revealed that MtRAV1 might inhibit the expression of Ferredoxin (MtFd-l3), Light-harvesting Chlorophyll a/b Binding Protein 1 (MtLhcb-l2) and Small Auxin Up-regulated RNA (MtSAUR-l), which related to photosystem II and auxin signaling pathway. Summarily, MtRAV1 was preliminarily proven to be a key growth inhibitory factor in M. truncatula.

Hormetic effect of a short-chain PFBS on Microcystis aeruginosa and its molecular mechanism

Short-chain Perfluorinated compounds (PFCs), used as substitutes for highly toxic long-chain PFCs, are increasingly entering the aquatic environment. However, the toxicity of short-chain PFCs in the environment is still controversial. This study investigated the effects of short-chain perfluorobutanesulfonic acid (PFBS) at different concentrations (2.5, 6, 14.4, 36, and 90 mg/L) on M. aeruginosa growth under 12-day exposure and explored the molecular mechanism of toxicity using transcriptomics. The results showed that M. aeruginosa exhibited hormetic effects after exposure to PFBS. Low PFBS concentrations stimulated algal growth, whereas high PFBS concentrations inhibited it, and this inhibitory effect became progressively more pronounced with increasing PFBS exposure concentrations. Transcriptomics showed that PFBS promoted the pathways of photosynthesis, glycolysis, energy metabolism and peptidoglycan synthesis, providing the energy required for cell growth and maintaining cellular morphology. PFBS, on the other hand, caused growth inhibition in algae mainly through oxidative stress, streptomycin synthesis, and genetic damage. Our findings provide new insights into the toxicity and underlying mechanism of short-chain PFCs on algae and inform the understanding of the hormetic effect of short-chain PFCs, which are crucial for assessing their ecological risks in aquatic environments.

Assessing phosphoglycolate phosphatase activity in C3 cereals: unveiling insights into photosynthesis and stress response

The article sheds new light on the biochemical and molecular mechanisms that connect plant respiration, photosynthesis, and photorespiration. The activity of the main enzyme of the photorespiratory C2 cycle, a major pathway of plant primary metabolism 2-Phosphoglycolate (2PG) phosphatase (PGLP; EC 3.1.3.18) was studied in the leaves of wheat (Triticum aestivum L. and Triticum durum L.) and barley (Hordeum vulgare L.) genotypes that differ in drought tolerance and belong to the C3 pathway of photosynthesis. The highest PGLP activity was detected in Barakatli 95, Gobustan, Dayanatli and Garabag 22 genotypes. The obtained results revealed that Gobustan and Garabagh 22 genotypes can be cultivated in rainfed and semi-arid regions, and can be used as a starting material for creating stress-tolerant varieties in practical breeding programs. Keywords: Drought stress, 2-Phosphoglycolate phosphatase (PGLP), C3 cereals, plant breeding

Improved Modeling of Gross Primary Production and Transpiration of Sugarcane Plantations with Time-Series Landsat and Sentinel-2 Images

Sugarcane croplands account for ~70% of global sugar production and ~60% of global ethanol production. Monitoring and predicting gross primary production (GPP) and transpiration (T) in these fields is crucial to improve crop yield estimation and management. While moderate-spatial-resolution (MSR, hundreds of meters) satellite images have been employed in several models to estimate GPP and T, the potential of high-spatial-resolution (HSR, tens of meters) imagery has been considered in only a few publications, and it is underexplored in sugarcane fields. Our study evaluated the efficacy of MSR and HSR satellite images in predicting daily GPP and T for sugarcane plantations at two sites equipped with eddy flux towers: Louisiana, USA (subtropical climate) and Sao Paulo, Brazil (tropical climate). We employed the Vegetation Photosynthesis Model (VPM) and Vegetation Transpiration Model (VTM) with C4 photosynthesis pathway, integrating vegetation index data derived from satellite images and on-ground weather data, to calculate daily GPP and T. The seasonal dynamics of vegetation indices from both MSR images (MODIS sensor, 500 m) and HSR images (Landsat, 30 m; Sentinel-2, 10 m) tracked well with the GPP seasonality from the EC flux towers. The enhanced vegetation index (EVI) from the HSR images had a stronger correlation with the tower-based GPP. Our findings underscored the potential of HSR imagery for estimating GPP and T in smaller sugarcane plantations.

Molecular characterization of a novel heat shock transcription factor gene TaHsfA2-11 and its overexpression improves thermotolerance in wheat

High temperature is a major constrait limiting the yield and quality of wheat. Wheat heat shock transcription factor (Hsf) plays important roles in regulating plant response to heat shock. In previous study, we found there are 82 Hsfs in wheat and TaHsfA2–11 expression was obviously upregulated by heat stress. In this study, we aim to investigate TaHsfA2–11 function and regulating mechanism in response to heat shock through genetic transformation into wheat Fielder. Gene expression analyses results showed that TaHsfA2–11 was expressed in all detected tissues and the most highly expressed level was in wheat mature roots. The expression level of TaHsfA2–11 was strongly upregulated by heat shock in wheat leaves. Subcellular localization results represented that TaHsfA2–11 is located to the nucleus. Transgenic wheat seedlings overexpressing TaHsfA2–11 showed stronger thermotolerance than the control Fielder after treated under 50 °C for 12 h. After heat shock, the TaHsfA2–11 overexpressing lines showed increased survival rate, chlorophyll content, POD (Peroxidase) activity, SOD (Superoxide dismutase) activity and photosynthetic rate, and decreased relative electrolyte leakage and MDA (malondialdehyde) content compared with Fielder. The results of RNA-sequence data demonstrated that TaHsfA2–11 can regulate many heat response genes, such as Hsp genes TaHsp16.6 and TaHsp21, ER (Endoplasmic reticulum) stress genes TaBiP2 and TaERDJ3A, photoprotectant for PSII gene TaELIPHV58, flavone biosynthesis related genes TaUGT-2A and TaPMaT, etc after heat stress. These results showed that TaHsfA2–11 can impove thermotolerance perhaps through effecting signal pathway of heat, ER stress, photosynthesis and ROS (Reactive Oxygen Species). The findings will provide useful gene resource for performing genetic modification of wheat thermotolerance in heat-resistant breeding.

Behavior and toxicity of silver nanoparticles to Chlorella vulgaris: A new perspective based on surface charges

The toxicity of silver nanoparticles (AgNPs) to algae is influenced by their surface charges. This study investigated the behavior and toxicity of two AgNPs modified by branched polyethyleneimine (BPEI-AgNPs with a positive charge) and citrate (CIT-AgNPs with a negative charge) on Chlorella vulgaris (C. vulgaris) to elucidate the surface charge-dependent toxicity of AgNPs to C. vulgaris. The results indicated that the BPEI-AgNPs exhibited a stronger inhibitory effect on the growth and photosynthetic activity of C. vulgaris, compared with the CIT-AgNPs. The reduction in the final superoxide dismutase content of 0.5 mg/L BPEI-AgNPs (48%) was higher than that of the CIT-AgNPs group (39%). The C. vulgaris exhibited less tolerance to the positively charged BPEI-AgNPs. The BPEI-AgNPs induced higher secretion of extracellular polymeric substances (EPS) and higher concentrations of lactate dehydrogenase (LDH) in C. vulgaris than CIT-AgNPs. The BPEI-AgNPs had a more significant up-regulation of gene expression for oxidative stress (sod2) than CIT-AgNPs, up to 2.57-fold. Genes encoding photosynthesis pathways were down-regulated, resulting in serious damage to photosynthetic system. Furthermore, the CIT-AgNPs inhibited the citrate cycle and oxidative phosphorylation metabolism, while BPEI-AgNPs disrupted the photophosphorylation pathways. These findings offer valuable insights into the effects of AgNPs with different surface charges on C. vulgaris.

Nitraria sibirica adapts to long-term soil water deficit by reducing photosynthesis, stimulating antioxidant systems, and accumulating osmoregulators

Amid climate change and shifts in precipitation patterns, drought conditions are expanding worldwide. Drought stress severely threatens plant growth in arid and semi-arid regions, wherein shrubs play a crucial role in maintaining ecological stability. Despite its ecological significance, studies are lacking on how Nitraria sibirica adapts to long-term drought stress. Therefore, in this study, to elucidate the mechanism of drought stress adaptation in N. sibirica, we analysed morphological, physiological, and transcriptional characteristics of plants in two soil habitats: riparian (moist) and desert (arid). The results showed that in desert soils, as soil water content decreased, leaf thickness increased, while plant height and leaf area decreased. Physiologically, photosynthesis decreased; soluble sugar, starch, proline, and hydrogen peroxide content increased significantly; while soluble proteins decreased significantly. Additionally, membrane lipid peroxidation products and antioxidant enzyme activities significantly increased under drought stress. Then, Kyoto Encyclopaedia of Genes and Genomes (KEGG) enrichment analysis identified 313 key genes, which were considered the most significantly enriched in the photosynthesis and photosynthetic antenna protein pathways. Further, we found that the proteins encoding photosystem II (PsbP, PsbQ, PsbR, PsbY, and Psb27), photosystem I (PsaD, PsaF, PsaG, PsaH, PsaK, and PsaO), photosynthetic electron transport (PetF), and light-trapping antenna proteins were significantly downregulated under drought stress. Taken together, these results suggest that N. sibirica adapts to long-term drought conditions by suppressing photosynthesis, activating antioxidant systems, and recruiting osmoregulators. This study provides a basis for elucidating the growth mechanisms of N. sibirica under long-term drought stress conditions.

Cell-Targeted Metal-Phenolic Nanoalgaecide in Hydroponic Cultivation to Enhance Food Sustainability.

The growing global population necessitates substantial increases in food production. Hydroponic cultivation systems afford a critical alternative for food sustainability and enable stable annual production regardless of the climatic and geographical variations. However, the overgrowth of harmful algal blooms significantly threatens the crop yield by competing with nutrition in the solution and producing contaminants. The conventional practice of algaecides fails to control algal proliferation due to the limited efficiency and food safety concerns. Nanopesticides can deliver active ingredients responsively to suppress crop diseases and offer solutions to current practical challenges and difficulties. Inspired by prospects of nanotechnology for agricultural applications, we have utilized natural polyphenols and copper ions (Cu2+ ions) to develop self-assembled nanoalgaecides referred to as CuBes. The nanoalgaecide attached to algal cells via phenolic surface interactions, enabling localized Cu2+ ion release. This cell-targeted delivery suppressed Chlorella vulgaris for over 30 days (99% inhibition). Transcriptomics revealed that the nanoalgaecide disrupted algal metabolism by downregulating photosynthesis and chlorophyll pathways. In a solar-illuminated plant factory, the nanoalgaecide showed higher algal inhibition and lettuce biosafety versus the commercial Kocide 3000. Notably, the use of nanoalgaecide can enhance the nutrient value of lettuces, which meets the daily supply of Cu for adults. By integrating smart nanotechnology design with selective delivery mechanisms, this metal-phenolic nanoalgaecide provides a nanoenabled solution for controlling harmful algal blooms in hydroponics to advance food production.

Fine mapping and candidate gene analysis of a major QTL for oil content in the seed of Brassica napus.

By integrating QTL fine mapping and transcriptomics, a candidate gene responsible for oil content in rapeseed was identified. The gene is anticipated to primarily function in photosynthesis and photosystem metabolism pathways. Brassica napus is one of the most important oil crops in the world, and enhancing seed oil content is an important goal in its genetic improvement. However, the underlying genetic basis for the important trait remains poorly understood in this crop. We previously identified a major locus, OILA5 responsible for seed oil content on chromosome A5 through genome-wide association study. To better understand the genetics of the QTL, we performed fine mapping of OILA5 with a double haploid population and a BC3F2 segregation population consisting of 6227 individuals. We narrowed down the QTL to an approximate 43kb region with twelve annotated genes, flanked by markers ZDM389 and ZDM337. To unveil the potential candidate gene responsible for OILA5, we integrated fine mapping data with transcriptome profiling using high and low oil content near-isogenic lines. Among the candidate genes, BnaA05G0439400ZS was identified with high expression levels in both seed and silique tissues. This gene exhibited homology with AT3G09840 in Arabidopsis that was annotated as cell division cycle 48. We designed a site-specific marker based on resequencing data and confirmed its effectiveness in both natural and segregating populations. Our comprehensive results provide valuable genetic information not only enhancing our understanding of the genetic control of seed oil content but also novel germplasm for advancing high seed oil content breeding in B. napus and other oil crops.

Analysis of the 2OG‐Fe (II) oxygenase family reveals new insights associated with flowering regulation in Saccharum spontaneum

AbstractPlant flowering is a crucial phenomenon affecting crop yield and crossbreeding. Saccharum spontaneum is the closest wild relative sugarcane species widely used in sugarcane genetic improvement. However, the molecular interactions among the components of the flowering regulatory network of S. spontaneum are still unclear. In this study, we conducted a transcriptome sequencing approach to analyze the expressed genes on four developmental stages of panicle samples in S. spontaneum. The weighted gene co‐expression network analysis (WGCNA) results suggested that genes from the MEred (p = 3 × 10−4) module were significantly enriched in pathways of ABC transporters, photosynthesis, and circadian rhythm‐plant. Thus, 23 genes associated with flower development‐related genes were screened, including 7 AGL24, 1 FLC, 3 VIN3, 3 GA20ox, and 9 ELF3. In the gibberellic acid (GA) synthesis pathway, GA20ox, GA3ox, and GA2ox were the three enzymes that catalyzed later reactions of GA biosynthesis and belong to the 2‐oxoglutarate Fe (II) oxygenase (2OG) superfamily. Flavonoid synthesis was promoted by 2‐oxoglutarate Fe (II) oxygenase genes, a flowering hormone, which catalyzed and oxidized naringenin to dihydrokaempferol, an important precursor of florigen. Genome‐wide analysis revealed that 122 Ss2OG genes were identified in S. spontaneum, of which 99 genes were enriched in the panicle transcriptome. Furthermore, a quantitative reverse transcription polymerase chain reaction analysis showed that Ss2OG‐FeII_Oxy90, Ss2OG‐FeII_Oxy47, and Ss2OG‐FeII_Oxy89 could introduce the flower development, while Ss2OG‐FeII_Oxy34, Ss2OG‐FeII_Oxy37, and Ss2OG‐FeII_Oxy50 inhibited it. These findings provide new clues and resources for exploring the molecular mechanism of flowering regulation in S. spontaneum and promoting sugarcane breeding.