摘要：
Capsaicinoids are naturally specialized metabolites in pepper and are the main reason that Capsicum fruits have a pungent smell. During the synthesis of capsaicin, MYB transcription factors play key regulatory roles. In particular, R2R3-MYB subfamily genes are the most important members of the MYB family and are critical candidate factors in capsaicinoid biosynthesis. The 108 R2R3-MYB genes in pepper were identified in this study and all are shown to have two highly conserved MYB binding domains. Phylogenetic and structural analyses clustered CaR2R3-MYB genes into seven groups. Interspecies collinearity analysis found that the R2R3-MYB family contains 16 duplicated gene pairs and the highest gene density is on chromosome 00 and 03. The expression levels of CaR2R3-MYB differentially expressed genes (DEGs) and capsaicinoid-biosynthetic genes (CBGs) in fruit development stages were obtained via RNA-seq and quantitative polymerase chain reaction (qRT-PCR). Co-expression analyses reveal that highly expressed CaR2R3-MYB genes are co-expressed with CBGs during early stages of pericarp and placenta development processes. It is speculated that six candidate CaR2R3-MYB genes are involved in regulating the synthesis of capsaicin and dihydrocapsaicin. This study is the first systematic analysis of the CaR2R3-MYB gene family and provided references for studying their molecular functions. At the same time, these results also laid the foundation for further research on the capsaicin characteristics of CaR2R3-MYB genes in pepper.
摘要：
The brown planthopper (BPH), Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), is a serious pest of rice. At present, the application of chemical insecticides is the main control option for this pest. BPH has evolved resistance to various classes of insecticides. Cycloxaprid, a new oxabridged cis-configuration neonicotinoid insecticide, is a (nitromethylene) imidazole analog of imidacloprid. This study focused on the baseline susceptibility to cycloxaprid of 18 field samples of N. lugens collected from nine geographical locations in China, as well as possible cross-resistances between cycloxaprid and other important neonicotinoids in one laboratory-selected resistant strain of N. lugens to imidacloprid. The median lethal concentration (LC50) of cycloxaprid for the 18 samples ranged from 1.26 to 14.90 mg/liter. Furthermore, the cross-resistance studies showed that the imidacloprid-resistant strain exhibited a 27.63-fold resistance to imidacloprid and lower levels of cross-resistance to acetamiprid (16.64-fold), thiacloprid (12.64-fold), and nitenpyram (16.90-fold); however, there was no cross-resistance to cycloxaprid (1.92-fold). These results indicate that cycloxaprid could be an effective alternative insecticide for the management of N. lugens, which is urgently needed to prevent or delay further increases in insecticide resistance in N. lugens.
摘要：
To investigate whether brassinosteroids (BR) affects cytokinin (CK)-induced anthocyanin biosynthesis, seedlings of the Arabidopsis dwarf4 (dwf4) mutants including partially suppressing coi1 (psc1) and dwf4-102, which are defective in the BR biosynthesis, and the brassinosteroid-insensitive 1-4 (bri1-4) mutant defective in BR signalling were used for the analysis of CK-induced anthocyanin accumulation and the expression of anthocyanin biosynthetic genes and WD-repeat/Myb/bHLH transcription factors. The results show that the CK-induced anthocyanin accumulation was remarkably reduced in dwf4 and bri1-4 mutants, but distinctly increased in the wild type (WT) treated with BR. Moreover, the CK-induced expressions of the late anthocyanin biosynthetic genes including dihydroflavonol reductase, leucoanthocyanidin dioxygenase, and UDP-glucose: flavonoid-3-O-glucosyl transferase were significantly reduced in bri1-4 and dwf4-102 mutants compared to WT. In addition, the expressions of transcription factors production of anthocyanin pigment 1 (PAP1), glabra 3 (GL3), and enhancer of glabra 3 (EGL3) were induced by CK in WT but not in the bri1-4 and dwf4-102 mutants. These results indicate that BR enhanced the CK-induced anthocyanin biosynthesis by up-regulating the late anthocyanin biosynthetic genes and this regulation might be mediated by the transcription factors PAP1, GL3, and EGL3.
摘要：
The hydrophobic nature of most membrane proteins severely complicates their extraction, proteolysis and identification. Although detergents can be used to enhance the solubility of the membrane proteins, it is often difficult for a detergent not only to have a strong ability to extract membrane proteins, but also to be compatible with the subsequent proteolysis and mass spectrometric analysis. In this study, we made evaluation on a novel application of sodium laurate (SL) to the shotgun analysis of membrane proteomes. SL was found not only to lyse the membranes and solubilize membrane proteins as efficiently as SDS, but also to be well compatible with trypsin and chymotrypsin. Furthermore, SL could be efficiently removed by phase transfer method from samples after acidification, thus ensuring not to interfere with the subsequent CapLC-MS/MS analysis of the proteolytic peptides of proteins. When SL was applied to assist the digestion and identification of a standard protein mixture containing bacteriorhodoposin and the proteins in rat liver plasma membrane-enriched fractions, it was found that, compared with other two representative enzyme- and MS-compatible detergents RapiGest SF (RGS) and sodium deoxycholate (SDC), SL exhibited obvious superiority in the identification of membrane proteins particularly those with high hydrophobicity and/or multiple transmembrane domains.
作者机构：
[Wang, Xianchun; Yan, Yizhong; Chen, Ping; He, Quanze; Liu, Yi; Li, Jianjun; Lin, Yong; Liang, Songping] Hunan Normal Univ, Coll Life Sci, Key Lab Prot Chem & Dev Biol, Natl Educ Comm, Changsha 410081, Hunan, Peoples R China.;[Lin, Yong] Hunan Agr Univ, Natl Res Ctr Engn & Technol Utilizat Bot Funct In, Coll Hort & Landscape, Changsha, Hunan, Peoples R China.
通讯机构：
[Wang, Xianchun] H;Hunan Normal Univ, Coll Life Sci, Key Lab Prot Chem & Dev Biol, Natl Educ Comm, Changsha 410081, Hunan, Peoples R China.
关键词：
Membrane proteome;Protein fractionation;Sample cleanup;SDS;Special gradient gel
摘要：
SDS is mostly used to enhance the solubilization and extraction of membrane proteins due to its strong detergency and low cost. Nevertheless, SDS interferes with the subsequent procedures and needs to be removed from the samples. In this work, a special gradient gel electrophoresis (GGE) system was developed to remove SDS from the SDS-solubilized protein samples. As a proof-of-principle experiment, the GGE system was designed to be composed of an agarose loading layer, six polyacrylamide fractionation layers with different concentrations and a high-concentration polyacrylamide sealing layer. The advantages of the GGE system are that it not only can electrophoretically remove SDS efficiently so that the protein loss resulted from the repeated gel washing after electrophoresis was avoided, but also can reduce the complexity of the sample, prevent the precipitation of proteins after loading and avoid the loss of proteins with low molecular weight during the electrophoresis. Using GGE system, about 85% of SDS in the sample and gel was electrophoretically removed and the proteins were fractionated. Compared with the two representative gel-based sample cleanup methods reported in literature, GGE-based strategy significantly improved the identification efficiency of proteins in terms of the number and coverage of the identified proteins.
摘要：
White leaf No.1 is a typical albino tea cultivar grown in China and it has received increased attention in recent years due to the fact that white leaves containing a high level of amino acids, which are very important components affecting the quality of tea drink. According to the color of its leaves, the development of this tea cultivar is divided into three stages: the pre-albinistic stage, the albinistic stage and the regreening stage. To understand the intricate mechanism of periodic albinism, a comparative proteomic approach based on two-dimensional electrophoresis (2-DE) and mass spectrometry was adopted first time to identify proteins that changed in abundance during the three developmental periods. The 2-DE results showed that the expression level of 61 protein spots varied markedly during the three developmental stages. To analyze the functions of the significantly differentially expressed protein spots, 30 spots were excised from gels and analyzed by matrix-assisted laser desorption ionization-time of flight-tandem mass spectrometry. Of these, 26 spots were successfully identified. All identified protein spots were involved in metabolism of carbon, nitrogen and sulfur, photosynthesis, protein processing, stress defense and RNA processing, indicating these physiological processes may play crucial roles in the periodic albinism. Quantitative real-time RT-PCR analysis was used to assess the transcriptional level of differentially expressed proteins. In addition, the ultrastructural studies revealed that the etioplast-chloroplast transition in the leaf cell of White leaf No. 1 was inhibited and the grana in the chloroplast was destroyed at the albinistic stage. In this work, the proteomic analysis revealed that some proteins may have important roles in the molecular events involved in periodic albinism of White leaf No. 1 and identificated many attractive candidates for further investigation. In addition, the ultrastructural studies revealed that the change in leaf color of White leaf No. 1 might be a consequence of suppression of the etioplast-chloroplast transition and damage to grana in the chloroplast induced by temperature. These results provide much useful information to improve our understanding of the mechanism of albinism in the albino tea cultivar.
作者机构：
[Krzysztof Górnik; Renato D. de Castro; Yongqing Liu; Raoul J. Bino; Steven P. C. Groot] Centre for Plant Breeding and Reproduction Research (CPRO-DLO), P.O. Box 16, 6700 AA Wageningen, Netherlands
通讯机构：
[Steven P. C. Groot] C;Centre for Plant Breeding and Reproduction Research (CPRO-DLO), P.O. Box 16, 6700 AA Wageningen, Netherlands
摘要：
Links between germination, DNA replication and β-tubulin accumulation were studied with cabbage (Brassica oleracea L.) seeds, by using flow cytometric analysis of nuclear DNA content and immunodetection of β-tubulin levels. The seeds were incubated in water or 0.1-500 mM hydroxyurea solutions. Radicle tips isolated from dry cabbage seeds revealed most 2C (G 0 or G 1 stage) and some 4C (G 2 stage) signals of nuclear DNA contents and a constitutive level of β-tubulin. The onset of DNA replication in the radicle tip was observed between 12 and 24 h of imbibition in water and was preceded by an increase of β-tubulin levels. Incubation of the seeds in 1 mM hydroxyurea retarded DNA replication, whereas an arrest of DNA replication occurred upon incubation in 10mM hydroxyurea or higher concentrations. The arrest of DNA replication and cell division did not block radicle protrusion and allowed some extension of the radicle. This demonstrated that DNA replication is not a prerequisite for radicle protrusion and initial extension. However, further seedling development, including root growth and root hair development, was dependent on DNA replication. Accumulation of β-tubulin was not affected by hydroxyurea. Thus, it can be deduced that both DNA replication and β-tubulin accumulation are two parallel and independent cell cycle events during seed germination.
摘要：
Using X-ray photography and flow cytometry, the internal morphology and DNA replication activity of wild type (wt), GA- ( gib-1 ) and ABA-deficient ( sit w ) tomato ( Lycopersicon esculentum Mill. cv. Moneymaker) mutant seeds were studied. During seed formation, from 30 to 45 d after pollination (DAP) the endosperm becomes solid and the seed starts to gain desiccation tolerance. At this time significant changes occur in the amounts of DNA in radicle tip cells. At 30 DAP, radicle tip cells of the three genotypes manifest about 60% of 2C, 30% of 4C and 10% of 8C amounts of DNA. Upon maturation (45 DAP onwards), most cells in the seeds of the three genotypes arrest in the G 1 phase of the cell-cycle with 2C amounts of DNA. However, a relatively high proportion of cells with 4C amounts of DNA was detected in the radicle tip cells of sit w compared with wild type and gib-1 . At the well-matured stage (60 DAP), there were about 2% of seeds with free space in wild type and gib-1 , and about 13% in sit w . At the over-matured stage (75 DAP), even more seeds with free space were found in sit w , whereas no increase in the proportion of the seeds with free space was detected in the other two genotypes. In −1.0 MPa PEG-6000 with or without 10 μ M GA 4+7 , no germination occurred in well-matured wild type and gib-1 seeds, whether or not they were dried after harvest. However, sit w seeds were able to germinate both in over-mature fruit and in −1.0 MPa PEG-6000. Priming of dried seeds in −1.0 MPa PEG induced a large amount of free space in almost all seeds of the three genotypes, and nuclear DNA synthesis in the radicle tip cells of wild type and sit w seeds. However, PEG priming of fresh (non-dried) seeds had no effect on the amount of free space and 2C/4C DNA ratios in wild type or gib-1 seeds, but did induce free space in about 20–25% of sit w seeds and provoked 4C signals in sit w seeds. Removal of the endosperm and testa opposite the radicle tip of seeds resulted in root protrusion, the induction of free space and an increase of 4C DNA signals in the three genotypes. It is concluded that ABA is crucial for the efficient arrest of tomato embryo radicle tip cells in G 1 phase upon maturation, whereas GAs play an important role in re-initiating 4C DNA levels upon germination.
摘要：
To explain the differing germination behaviour of seeds of wild type, gibberellin-deficient (gib1) or abscisic acid-deficient (sit(w)) mutants of tomato (Lycopersicon esculentum Mill. cv. Moneymaker), growth and water relations of fruit tissues, seeds and embryos were determined during development. The objective was to determine whether the hormones influenced water relations of fruit and seed tissues and as a consequence germinability. Despite the up to 70% lower fruit weight of the mutants, the fresh and dry seed weights were similar to that of the wild type. Water relations of pericarp and locular tissues in wild type and gib1 fruits were characterized by a slowly increasing Psi(pi) that reached a constant value Psi of -0.60 MPa at 35-40 days after anthesis, resulting in a complete loss of turgor. However, sit(w) fruit tissues maintained their turgor throughout development, mainly as a result of considerably lower Psi(pi) values but similar Psi values compared with the other genotypes. The Psi of wild type and gib1 seeds decreased from -0.50 to -0.80 MPa and Psi(pi) from -0.80 to -1.00 MPa between day 30 and 40. From day 40 onwards, Psi(p) was similar in both genotypes, approximately 0.20 MPa. As in the fruit tissues, sit(w) seed water relations were also characterized by higher turgor values than the other genotypes. Up to day 40, Psi(p) was ca 0.40 MPa, dropped temporarily to zero, and increased again to approximately 0.40 MPa at day 50. Embryo water relations of both mutants deviated from the wild type in that Psi(p) of the gib1 and sit(w) embryos remained at 3.5 MPa and 2.5 MPa, respectively, from day 40 onward, whereas in wild type embryos Psi(p) decreased from 3.0 MPa at day 35 to approximately 1.0 MPa at 50 days after anthesis. This was mainly due to an increasing Psi(pi) which was absent in the mutants. Throughout development there was equilibrium between Psi of pericarp, locular tissues and seeds but between embryo and seed or fruit tissues Psi gradients of up to 1.5 MPa were calculated in the wild type, and up to 1.0 MPa in the mutants. Thus, precocious germination is prevented by the action of the fruit's osmotic environment and ABA on the seed tissues surrounding the embryo and not the embryo itself. Embryos have a Psi which is low enough to overcome the solute potential of the fruit tissues throughout development.
