S45A, a double recessive mutant at both the BnMs1 and BnMs2 loci in Brassica napus, produces no pollen in mature anthers and no seeds by self-fertilization. The BnMs1 and BnMs2 genes, which have ...redundant functions in the control of male fertility, are positioned on linkage groups N7 and N16, respectively, and are located at the same locus on Arabidopsis chromosome 1 based on collinearity between Arabidopsis and Brassica. Complementation tests indicated that one candidate gene, BnCYP704B1, a member of the cytochrome P450 family, can rescue male sterility. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of the developing anther showed that pollen-wall formation in the mutant was severely compromised, with a lack of sporopollenin or exine. The phenotype was first evident at the tetrad stage (stage 7) of anther development, coinciding with the maximum BnCYP704B1 mRNA accumulation observed in tapetal cells at stages 7-8 (haploid stage). TEM also suggested that development of the tapetum was seriously defective due to the disturbed lipid metabolism in the S45A mutant. A TUNEL assay indicated that the pattern of programmed cell death in the tapetum of the S45A mutant was defective. Lipid analysis showed that the total fatty acid content was reduced in the S45A mutant, indicating that BnCYP704B1 is involved in lipid metabolism. These data suggest that BnCYP704B1 participates in a vital tapetum-specific metabolic pathway that is not only involved in exine formation but is also required for basic tapetal cell development and function.
Ultrafast ultrasound imaging has been demonstrated to be an effective method to evaluate carotid stiffness through carotid pulse-wave velocity (PWV) with high reproducibility, but a lack of reference ...values has precluded its widespread use in clinical practice. The aims of this study were to establish reference values of PWV for ultrafast ultrasound imaging in a prospective, multicenter, population-based cohort study and to investigate the main determinants of carotid PWV.
A total of 1,544 healthy Han Chinese volunteers (581 men 38%; age range, 18–95 years) were enrolled from 32 collaborating laboratories in China. The participants were categorized by age, blood pressure (BP), and body mass index (BMI). Basic clinical parameters and carotid PWV at the beginning of systole (BS) and at end-systole (ES) were measured using ultrafast ultrasound imaging techniques.
PWV at both BS and ES was significantly higher in the left carotid artery than in the right carotid artery. PWV at BS was significantly higher in men than in women; however, no significant difference was noted in PWV at ES between men and women. Multiple linear regression analyses revealed that age, BP, and BMI were independently correlated with PWV at both BS and ES. PWV at BS and ES progressively increased with increases in age, BP, and BMI. Furthermore, age- and sex-specific reference values of carotid PWV for ultrafast ultrasound imaging were established.
Reference values of carotid PWV for ultrafast ultrasound imaging, stratified by sex and age, were determined for the first time. Age, BP, and BMI were the dominant determinants of carotid PWV for ultrafast ultrasound imaging, which should be considered in clinical practice for assessing arterial stiffness.
•Ultrafast ultrasound imaging is a new method to evaluate arterial stiffness with PWV.•The lack of reference values of PWV has precluded its widespread clinical use.•This study established reference values of PWV based on a Han Chinese population.•Age, BP, and BMI were the dominant determinants of PWV.
•The EAF of NNL shows superior inhibition on AGEs than aminoguanidine.•The inhibitory mechanism was elucidated by high resolution mass spectrometry.•NNL extracts attenuate the conformational change ...of BSA induced by glycation.•11 and 10 glycation sites were identified from glycated BSA with and without EAF, respectively.•EAF does not reduce the glycation sites, but decrease the DSP and alter the location.
The inhibition of Nelumbo nucifera leaf (NNL) extract and its fractions on the formation of advanced glycation end-products (AGEs) was evaluated with different models. Changes in the conformational structure of bovine serum albumin (BSA) were analyzed by fluorescence spectrometry. Effect of ethyl acetate fraction (EAF) on the glycation sites and glycation degree of BSA was investigated by Nano LC-Orbitrap-MS/MS due to its strongest inhibitory ability. Results indicated that EAF could effectively inhibit the formation of AGEs by scavenging reactive radicals and attenuating the conformational change of BSA induced by glycation. Phenolics and flavonoids were the major contributors. Eleven (11 lysines) and ten (9 lysines and 1 arginine) glycation sites were identified from glycated BSA with and without EAF, respectively. Addition of EAF could not reduce the number of glycation sites of BSA, but could significantly decrease the glycation degree of most glycated peptides and alter the location of glycation.
Light is one of the most important factors regulating plant growth and development. Light-sensing photoreceptors tightly regulate gene expression to control photomorphogenic responses. Although many ...levels of gene expression are modulated by photoreceptors, regulation at the mRNA splicing step remains unclear.
We performed high-throughput mRNA sequencing to analyze light-responsive changes in alternative splicing in the moss Physcomitrella patens, and found that a large number of alternative splicing events were induced by light in the moss protonema. Light-responsive intron retention preferentially occurred in transcripts involved in photosynthesis and translation. Many of the alternatively spliced transcripts were expressed from genes with a function relating to splicing or light signaling, suggesting a potential impact on pre-mRNA splicing and photomorphogenic gene regulation in response to light. Moreover, most light-regulated intron retention was induced immediately upon light exposure, while motif analysis identified a repetitive GAA motif that may function as an exonic regulatory cis element in light-mediated alternative splicing. Further analysis in gene-disrupted mutants was consistent with a function for multiple red-light photoreceptors in the upstream regulation of light-responsive alternative splicing.
Our results indicate that intensive alternative splicing occurs in non-vascular plants and that, during photomorphogenesis, light regulates alternative splicing with transcript selectivity. We further suggest that alternative splicing is rapidly fine-tuned by light to modulate gene expression and reorganize metabolic processes, and that pre-mRNA cis elements are involved in photoreceptor-mediated splicing regulation.
Cadmium is a potentially toxic heavy metal to human health. Rapeseed (
L.), a vegetable and oilseed crop, might also be a Cd hyperaccumulator, but there is little information on this trait in ...rapeseed. We evaluated Cd accumulation in different oilseed accessions and employed a genome-wide association study to identify quantitative trait loci (QTLs) related to Cd accumulation. A total of 419
accessions and inbred lines were genotyped with a 60K Illumina Infinium SNP array of Brassica. Wide genotypic variations in Cd concentration and translocation were found. Twenty-five QTLs integrated with 98 single-nucleotide polymorphisms (SNPs) located at 15 chromosomes were associated with Cd accumulation traits. These QTLs explained 3.49-7.57% of the phenotypic variation observed. Thirty-two candidate genes were identified in these genomic regions, and they were 0.33-497.97 kb away from the SNPs. We found orthologs of
located near the significant SNPs on the
genome, including NRAMP6 (natural resistance-associated macrophage protein 6), IRT1 (iron-regulated transporter 1), CAD1 (cadmium-sensitive 1), and PCS2 (phytochelatin synthase 2). Of them, four candidate genes were verified by qRT-PCR, the expression levels of which were significantly higher after exposure to Cd than in the controls. Our results might facilitate the study of the genetic basis of Cd accumulation and the cloning of candidate Cd accumulation genes, which could be used to help reduce Cd levels in edible plant parts and/or create more efficient hyperaccumulators.
Pichia pastoris
is an efficient host for the expression and secretion of heterologous proteins and the most important feature of
P. pastoris
is the existence of a strong and tightly regulated ...promoter from the alcohol oxidase I (AOX1) gene. The AOX1 promoter (pAOX1) has been used to express foreign genes and to produce a variety of recombinant proteins in
P. pastoris
. However, some efforts have been made to develop new alternative promoters to pAOX1 to avoid the use of methanol. The glyceraldehyde-3-phosphate dehydrogenase promoter (pGAP) has been used for constitutive expression of many heterologous proteins. The pGAP-based expression system is more suitable for large-scale production because the hazard and cost associated with the storage and delivery of large volume of methanol are eliminated. Some important developments and features of this expression system will be summarized in this review.
Introduction
Salicylic acid (SA) is a multi-functional endogenous phytohormone implicated in the growth, development, and metabolism of many plant species.
Methods
This study evaluated the effects of ...different concentrations of SA (0, 25, 100, 200, and 500 mg/L) on the growth and cadmium (Cd) content of lettuce (
Lactuca sativa
L.) under Cd stress. The different concentrations of SA treatments were administered through foliar application.
Results
Our results showed that 100-200 mg/L SA significantly increased the plant height and biomass of lettuce under Cd stress. When SA concentration was 200 mg/L, the plant height and root length of lettuce increased by 19.42% and 22.77%, respectively, compared with Cd treatment alone. Moreover, 200 mg/L and 500mg/L SA concentrations could reduce peroxidase (POD) and superoxide dismutase (SOD) activities caused by Cd stress. When the concentration of exogenous SA was 500 mg/L, the POD and SOD activities of lettuce leaves decreased by 15.51% and 19.91%, respectively, compared with Cd treatment. A certain concentration of SA reduced the uptake of Cd by the lettuce root system and the transport of Cd from the lettuce root system to shoots by down-regulating the expression of
Nramp5
,
HMA4
, and
SAMT
, thus reducing the Cd content of lettuce shoots. When the concentration of SA was 100 mg/L, 200 mg/L, and 500 mg/L, the Cd contents of lettuce shoots were 11.28%, 22.70%, and 18.16%, respectively, lower than that of Cd treatment alone. Furthermore, principal component and correlation analyses showed that the Cd content of lettuce shoots was correlated with plant height, root length, biomass, antioxidant enzymes, and the expression level of genes related to Cd uptake.
Discussion
In general, these results provide a reference for the mechanism by which SA reduces the Cd accumulation in vegetables and a theoretical basis for developing heavy metal blockers with SA components.
The Polima (pol) system of cytoplasmic male sterility (CMS) and its fertility restoration gene Rfp have been used in hybrid breeding in Brassica napus, which has greatly improved the yield of ...rapeseed. However, the mechanism of the male sterility transition in pol CMS remains to be determined.
To investigate the transcriptome during the male sterility transition in pol CMS, a near-isogenic line (NIL) of pol CMS was constructed. The phenotypic features and sterility stage were confirmed by anatomical analysis. Subsequently, we compared the genomic expression profiles of fertile and sterile young flower buds by RNA-Seq. A total of 105,481,136 sequences were successfully obtained. These reads were assembled into 112,770 unigenes, which composed the transcriptome of the bud. Among these unigenes, 72,408 (64.21%) were annotated using public protein databases and classified into functional clusters. In addition, we investigated the changes in expression of the fertile and sterile buds; the RNA-seq data showed 1,148 unigenes had significantly different expression and they were mainly distributed in metabolic and protein synthesis pathways. Additionally, some unigenes controlling anther development were dramatically down-regulated in sterile buds.
These results suggested that an energy deficiency caused by orf224/atp6 may inhibit a series of genes that regulate pollen development through nuclear-mitochondrial interaction. This results in the sterility of pol CMS by leading to the failure of sporogenous cell differentiation. This study may provide assistance for detailed molecular analysis and a better understanding of pol CMS in B. napus.
In cruciferous plants, SI is determined by the S locus, which harbors genes encoding the stigma papilla cell‐specific S‐receptor kinase (SRK) and the pollen surface‐localized ligand of SRK, S‐locus ...cysteine‐rich protein/S‐locus protein 11 (SCR/SP11) (Schopfer et al., 1999; Suzuki et al., 1999). In B. rapa, the linear dominance hierarchy of class II S haplotype SCR alleles is controlled by SCR‐methylation‐inducing region 2 (Smi2) in the S locus; the Smi2 of the dominant S locus generates small interfering RNAs (siRNAs), which suppresses the expression of the recessive S‐locus SCR by siRNA‐mediated DNA methylation (e.g., BrS44 > BrS60 > BrS40 > BrS29, Yasuda et al., 2016). BoS15 and BrS60 are interspecific pairs between B. oleracea and B. rapa based on their high sequence similarity and incompatibility of B. oleracea BoS15 pollen with BrS60/BoS18 interspecific hybrid stigmas (Sato et al., 2006). ...BrS29 could be deduced to be recessive to BoS15.
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