A point mutation in the photosystem I P700 chlorophyll a apoprotein A1 gene confers variegation in Helianthus annuus L

Evaluation of the Aquatic Toxicity of Several Triazole Fungicides

Fungicides play an important role in crop protection, but they have also been shown to adversely affect non-target organisms, including those living in the aquatic environment. The aim of the present study is to combine experimental and computational approaches to evaluate the effects of flutriafol, metconazole, myclobutanil, tebuconazole, tetraconazole and triticonazole on aquatic model organisms and to obtain information on the effects of these fungicides on Lemna minor, a freshwater plant, at the molecular level. The EC50 (the half-maximum effective concentration) values for the growth inhibition of Lemna minor in the presence of the investigated fungicides show that metconazole (EC50 = 0.132 mg/L) and tetraconazole (EC50 = 0.539 mg/L) are highly toxic, tebuconazole (EC50 = 1.552 mg/L), flutriafol (EC50 = 3.428 mg/L) and myclobutanil (EC50 = 9.134 mg/L) are moderately toxic, and triticonazole (EC50 = 11.631 mg/L) is slightly toxic to this plant. The results obtained with the computational tools TEST, ADMETLab2.0 and admetSAR2.0 also show that metconazole and tetraconazole are toxic to other aquatic organisms: Pimephales promelas, Daphnia magna and Tetrahymena pyriformis. A molecular docking study shows that triazole fungicides can affect photosynthesis in Lemna minor because they strongly bind to C43 (binding energies between -7.44 kcal/mol and -7.99 kcal/mol) and C47 proteins (binding energies between -7.44 kcal/mol and -8.28 kcal/mol) in the reaction center of photosystem II, inhibiting the binding of chlorophyll a to these enzymes. In addition, they can also inhibit glutathione S-transferase, an enzyme involved in the cellular detoxification of Lemna minor.

Development of InDels markers for the identification of cytoplasmic male sterility in Sorghum by complete chloroplast genome sequences analysis

Cytoplasmic male sterility (CMS) is predominantly used for F1 hybrid breeding and seed production in Sorghum. DNA markers to distinguish between normal fertile (CMS-N) and sterile (CMS-S) male cytoplasm can facilitate F1 hybrid cultivar development in Sorghum breeding programs. In this study, the complete chloroplast (cp) genome sequences of CMS-S and Korean Sorghum cultivars were obtained using next-generation sequencing. The de novo assembled genome size of ATx623, the CMS-S line of the chloroplast, was 140,644bp. When compared to the CMS-S and CMS-N cp genomes, 19 single nucleotide polymorphisms (SNPs) and 142 insertions and deletions (InDels) were identified, which can be used for marker development for breeding, population genetics, and evolution studies. Two InDel markers with sizes greater than 20 bp were developed to distinguish cytotypes based on the copy number variation of lengths as 28 and 22 bp tandem repeats, respectively. Using the newly developed InDel markers with five pairs of CMS-S and their near isogenic maintainer line, we were able to easily identify their respective cytotypes. The InDel markers were further examined and applied to 1,104 plants from six Korean Sorghum cultivars to identify variant cytotypes. Additionally, the phylogenetic analysis of seven Sorghum species with complete cp genome sequences, including wild species, indicated that CMS-S and CMS-N contained Milo and Kafir cytotypes that might be hybridized from S. propinquum and S. sudanese, respectively. This study can facilitate F1 hybrid cultivar development by providing breeders with reliable tools for marker-assisted selection to breed desirable Sorghum varieties.

Genetic and transcriptome analysis of a cotton leaf variegation mutant

In eukaryotic photosynthetic organisms, chloroplast is not only a site for photosynthesis, but it also have a vital role in signal transduction mechanisms. Plants exhibit various colors in nature with various mutants induced by EMS, whose traits are regulated by developmental and environmental factors, making them ideal for studying the regulation of chloroplast development. In this study, the cotton leaf variegated mutant (VAR) induced by EMS was used for this experiment. Genetic analysis revealed that VAR phenotype was a dominant mutation and by performing freehand section inspection, it was noticed that the vascular bundles of VAR were smaller. Chloroplast ultrastructure showed that the stacking of grana thylakoid was thinner and the starch granules were increased significantly in VAR comparedto wild type (WT). Transcriptome analysis found that the KEGG was enriched in photosynthesis pathway, and GO was abundant in zinc ion transmembrane transport, electron transporter and cation binding terms. In addition, GhFTSH5 expression in VAR was significantly higher than WT and the promoter sequence of GhFTSH5 had differences. The results showed that the VAR plant had altered GhFTSH5 expression and disrupted chloroplast structure, which in turn affects plant photosynthesis. More importantly, this study lays a foundation for further analyzing molecular mechanism of cotton variegated phenotypes.

Effects of bulk and nano-ZnO particles on functioning of photosynthetic apparatus in barley (Hordeum vulgare L.)

The functioning of the photosynthetic apparatus in barley (Hordeum vulgare L.) after 7-days of exposure to bulk (b-ZnO) and nanosized ZnO (n-ZnO) (300, 2000, and 10,000 mg/l) has been investigated. An impact on the amount of chlorophylls, photosynthetic efficiency, as well as the zinc accumulation in chloroplasts was demonstrated. Violation of the chloroplast fine structure was revealed. These changes were generally more pronounced with n-ZnO exposure, especially at high concentrations. For instance, the chlorophyll deficiency under 10,000 mg/l b-ZnO treatment was 31% and with exposure to 10,000 mg/l n-ZnO, the chlorophyll deficiency was already 52%. The expression analysis of the photosynthetic genes revealed their different sensitivity to b-ZnO and n-ZnO exposure. The genes encoding subunits of photosystem II (PSII) and, to a slightly lesser extent, photosystem I (PSI) showed the highest suppression of transcriptional levels. The mRNA levels of the subunits of cytochrome-b₆f, NADH dehydrogenase, ribulose-1,5-bisphosphate carboxylase and ATP synthase, which, in addition to linear electron flow (LEF), participate in cyclic electron flow (CEF) and autotrophic CO₂ fixation, were more stable or increased under b-ZnO and n-ZnO treatments. At the same time, CEF was increased. It was assumed that under the action of b-ZnO and n-ZnO, the processes of LEF are disrupted, and CEF is activated. This allows the plant to prevent photo-oxidation and compensate for the lack of ATP for the CO₂ fixation process, thereby ensuring the stability of photosynthetic function in the initial stages of stress factor exposure. The study of photosynthetic structures of crops is important from the point of view of understanding the risks of reducing the production potential and the level of food security due to the growing use of nanoparticles in agriculture.

High-throughput discovery of plastid genes causing albino phenotypes in ornamental chimeric plants

Chimeric plants composed of green and albino tissues have great ornamental value. To unveil the functional genes responsible for albino phenotypes in chimeric plants, we inspected the complete plastid genomes (plastomes) in green and albino leaf tissues from 23 ornamental chimeric plants belonging to 20 species, including monocots, dicots, and gymnosperms. In nine chimeric plants, plastomes were identical between green and albino tissues. Meanwhile, another 14 chimeric plants were heteroplasmic, showing a mutation between green and albino tissues. We identified 14 different point mutations in eight functional plastid genes related to plastid-encoded RNA polymerase (rpo) or photosystems which caused albinism in the chimeric plants. Among them, 12 were deleterious mutations in the target genes, in which early termination appeared due to small deletion-mediated frameshift or single nucleotide substitution. Another was single nucleotide substitution in an intron of the ycf3 and the other was a missense mutation in coding region of the rpoC2 gene. We inspected chlorophyll structure, protein functional model of the rpoC2, and expression levels of the related genes in green and albino tissues of Reynoutria japonica. A single amino acid change, histidine-to-proline substitution, in the rpoC2 protein may destabilize the peripheral helix of plastid-encoded RNA polymerase, impairing the biosynthesis of the photosynthesis system in the albino tissue of R. japonica chimera plant.

Clinical Efficacy of Huangkui Capsule plus Methylprednisolone in the Treatment of Nephropathy and the Effect on Urinary Protein and Serum Inflammatory Factors in Patients

Objective

The study aimed to assess the clinical efficacy of Huangkui capsule plus methylprednisolone in the treatment of nephropathy and the effect on urinary protein and serum inflammatory factors in patients.

Methods

Between June 2017 and July 2020, 90 patients with nephropathy admitted to our hospital were recruited after assessment of eligibility and assigned via the random number table method (1 : 1) to receive either methylprednisolone tablets (observation group) or methylprednisolone tablets plus Huangkui capsules (experimental group). All eligible patients were also given dipyridamole and valsartan. Outcome measures included clinical efficacy, urine protein, hematuria, serum inflammatory factor levels, and adverse reactions.

Results

A higher clinical efficacy was observed in the experimental group versus the observation group (P < 0.05). Huangkui capsules resulted in significantly lower levels of urine protein and hematuria in the experimental group versus the observation group after treatment (P < 0.05). The serum tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and monocyte chemoattractant protein-1 (MCP-1) levels in the experimental group were significantly lower than those in the observation group after treatment (P < 0.05). Huangkui capsules plus methylprednisolone were associated with a lower incidence of adverse events versus methylprednisolone (P < 0.05).

Conclusion

The clinical efficacy of Huangkui capsule plus methylprednisolone in the treatment of patients with nephropathy is remarkable. It can effectively mitigate the inflammatory responses and enhance renal function, with reliable clinical safety, so it is worthy of clinical application.

Mendelian and non-Mendelian genetics in model plants

The "Mendelian Rules" of inheritance are cornerstones of genetics, described in Mendel's seminal publication from 1866. The experimental results and their interpretation have been discussed in numerous ways. This perspective emphasizes the contribution of Mendel's preparations prior to his crossing experiments to the discovery of Mendelian genetics. This thoughtful experimental design, and some fortune, avoided pitfalls that could have resulted in non-Mendelian inheritance.

Effects of ZnO nanoparticles and its bulk form on growth, antioxidant defense system and expression of oxidative stress related genes in Hordeum vulgare L

A comparative analysis of physio-biochemical indices and transcriptional activity of oxidative stress genes in barley (Hordeum vulgare L.) seedlings after 7-days exposure to bulk- and nano-ZnO (300 and 2000 mg/L) was carried out. A dose-dependent reduction in the length and weight of roots and shoots, as well as a significant accumulation of Zn in plant parts, was shown. Alterations in the shape and size of organelles, cytoplasmic vacuolization, and chloroplast and mitochondrial disorganization were also revealed. These processes are particularly pronounced when H. vulgare is exposed to the higher concentrations of nano-ZnO. The study of the antioxidant defense system revealed mainly an increase in the level of reduced glutathione and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione S-transferase (GST). The increases in activity, by 4-fold and 3-fold, was found for glutathione transferase in the roots when exposed to 2000 mg/L bulk- and nano-ZnO, respectively. The study of transcriptional activity demonstrated that in the roots under the influence of bulk- and nano-ZnO, along with Mn-SOD, Fe-SOD is highly expressed, mainly associated with the protection of chloroplasts. Analysis of the Cat 1 and Cat 2 gene expression showed that the main contribution to the increase in catalase activity in treated H. vulgare is made by the CAT-1 isozyme. Generally, in response to the impact of the studied ZnO forms, the antioxidant defense system is activated in H. vulgare, which effectively prevents the progression of oxidative stress in early stages of plant ontogenesis. Nevertheless, with constant exposure to bulk- and nano-ZnO at high concentrations, such activation leads to a depletion of the plant's energy resources, which negatively affects its growth and development. The results obtained could be useful in predicting the risks associated with the further transfer of nano-ZnO to the environment.

Proteomics and Interspecies Interaction Analysis Revealed Abscisic Acid Signalling to Be the Primary Driver for Oil Palm's Response against Red Palm Weevil Infestation

The red palm weevil (RPW; Rhynchophorus ferrugineus Olivier (Coleoptera Curculionidae)) is an invasive insect pest that is difficult to manage due to its nature of infesting the host palm trees from within. A holistic, molecular-based approach to identify proteins that correlate with RPW infestation could give useful insights into the vital processes that are prevalent to the host's infestation response and identify the potential biomarkers for an early detection technique. Here, a shotgun proteomic analysis was performed on oil palm (Elaeis guineensis; OP) under untreated (control), wounding by drilling (wounded), and artificial larval infestation (infested) conditions at three different time points to characterise the RPW infestation response at three different stages. KEGG pathway enrichment analysis revealed many overlapping pathways between the control, wounded, and infested groups. Further analysis via literature searches narrowed down biologically relevant proteins into categories, which were photosynthesis, growth, and stress response. Overall, the patterns of protein expression suggested abscisic acid (ABA) hormone signalling to be the primary driver of insect herbivory response. Interspecies molecular docking analysis between RPW ligands and OP receptor proteins provided putative interactions that result in ABA signalling activation. Seven proteins were selected as candidate biomarkers for early infestation detection based on their relevance and association with ABA signalling. The MS data are available via ProteomeXchange with identifier PXD028986. This study provided a deeper insight into the mechanism of stress response in OP in order to develop a novel detection method or improve crop management.

Characterization and transcriptomic analysis of a novel yellow-green leaf wucai (Brassica campestris L.) germplasm

BACKGROUND

Leaf color mutants are the ideal materials to explore the pathways of chlorophyll (Chl) metabolism, chloroplast development, and photosynthesis system. In this study, a spontaneous yellow-green leaf wucai (Brassica campestris L.) mutant "WY16-13" was identified, which exhibited yellow-green leaf color during its entire growth period. However, current understanding of the molecular mechanism underlying Chl metabolism and chloroplast development of "WY16-13" is limited.

RESULTS

Total Chl and carotenoid content in WY16-13 was reduced by 60.92 and 58.82%, respectively, as compared with its wild type parental line W16-13. Electron microscopic investigation revealed fewer chloroplasts per cell and looser stroma lamellae in WY16-13 than in W16-13. A comparative transcriptome profiling was performed using leaves from the yellow-green leaf type (WY16-13) and normal green-leaf type (W16-13). A total of 54.12 million (M) (WY16-13) and 56.17 M (W16-13) reads were generated. A total of 40,578 genes were identified from the mapped libraries. We identified 3882 differentially expressed genes (DEGs) in WY16-13 compared with W16-13 (i.e., 1603 upregulated genes and 2279 downregulated genes). According to the Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, these DEGs are involved in porphyrin and Chl metabolism [i.e., chlorophyllase (CLH), heme oxygenase (HO), chlorophyll (ide) b reductase (NYC), and protochlorophyllide oxidoreductase (POR) genes], carbohydrate metabolism, photosynthesis, and carbon fixation in photosynthetic organisms. Moreover, deficiency in Chl biosynthetic intermediates in WY16-13 revealed that the formation of the yellow-green phenotype was related to the disorder of heme metabolism.

CONCLUSIONS

Our results provide valuable insights into Chl deficiency in the yellow-green leaf mutant and a bioinformatics resource for further functional identification of key allelic genes responsible for differences in Chl content.

Cytological and Transcriptomic Analysis Provide Insights into the Formation of Variegated Leaves in Ilex × altaclerensis 'Belgica Aurea'

Ilex × altaclerensis 'Belgica Aurea' is an attractive ornamental plant bearing yellow-green variegated leaves. However, the mechanisms underlying the formation of leaf variegation in this species are still unclear. Here, the juvenile yellow leaves and mature variegated leaves of I. altaclerensis 'Belgica Aurea' were compared in terms of leaf structure, pigment content and transcriptomics. The results showed that no obvious differences in histology were noticed between yellow and variegated leaves, however, ruptured thylakoid membranes and altered ultrastructure of chloroplasts were found in yellow leaves (yellow) and yellow sectors of the variegated leaves (variegation). Moreover, the yellow leaves and the yellow sectors of variegated leaves had significantly lower chlorophyll compared to green sectors of the variegated leaves (green). In addition, transcriptomic sequencing identified 1675 differentially expressed genes (DEGs) among the three pairwise comparisons (yellow vs. green, variegation vs. green, yellow vs. variegation). Expression of magnesium-protoporphyrin IX monomethyl ester (MgPME) [oxidative] cyclase, monogalactosyldiacylglycerol (MGDG) synthase and digalactosyldiacylglycerol (DGDG) synthase were decreased in the yellow leaves. Altogether, chlorophyll deficiency might be the main factors driving the formation of leaf variegation in I.altaclerensis 'Belgica Aurea'.