Genetics of allozyme variation in Gossypium arboreum L. and Gossypium herbaceum L. (Malvaceae)

Summary Seed protein extracts from 90 accessions of Gossypium arboreum and 70 accessions of Gossypium herbaceum were electrophoretically analyzed for isozyme variation. Eighteen enzyme systems were resolved, ten of which were polymorphic among accessions. No within accession isozyme variation was observed within these highly inbred lines. A minimum of 24 genes encode the isozymes resolved and data is presented for codominant inheritance at 13 loci. Tests for non-random joint segregation in 63 of the 78 possible two-locus combinations from the 13 characterized loci give evidence for four pairs of linked genes (Lap2/Me1 [r=0.160+/-0.027], Lap2/Pgi1 [r= 0.285+/-0.055], Mdh6/Tpi1 [r= 0.197+/-0.028], and 6Pgd2/6Pgd3[r 0.000]. Numerous presumptive duplicate isozyme loci were observed and these were usually expressed as patterns of nonsegregating heteromultimers within accessions. Single gene expression was also observed at several loci. The observed results are in agreement with those of previous cytological investigations which have proposed the polyploid origin of the diploid Old World Gossypiums.     

Improved Reconstruction of In Silico Gene Regulatory Networks by Integrating Knockout and Perturbation Data

We performed computational reconstruction of the in silico gene regulatory networks in the DREAM3 Challenges. Our task was to learn the networks from two types of data, namely gene expression profiles in deletion strains (the ‘deletion data’) and time series trajectories of gene expression after some initial perturbation (the ‘perturbation data’). In the course of developing the prediction method, we observed that the two types of data contained different and complementary information about the underlying network. In particular, deletion data allow for the detection of direct regulatory activities with strong responses upon the deletion of the regulator while perturbation data provide richer information for the identification of weaker and more complex types of regulation. We applied different techniques to learn the regulation from the two types of data. For deletion data, we learned a noise model to distinguish real signals from random fluctuations using an iterative method. For perturbation data, we used differential equations to model the change of expression levels of a gene along the trajectories due to the regulation of other genes. We tried different models, and combined their predictions. The final predictions were obtained by merging the results from the two types of data. A comparison with the actual regulatory networks suggests that our approach is effective for networks with a range of different sizes. The success of the approach demonstrates the importance of integrating heterogeneous data in network reconstruction.     

Influence of explants, genotypes and culture vessels on sprouting and proliferation of pre-existing meristems of cotton (Gossypium hirsutum L. and Gossypium arboreum L.)

Summary A simple and efficient method for multiple shoot induction and proliferation was achieved in six Indian cotton cultivars from the pre-existing meristems of 21-d-old in vitro-grown seedlings. Combinations of naphthalene acetic acid (0.3–10.7 μM) and 6-benzylaminopurine (BA; 2.2 or 4.4 μM) were used for induction of shoots. The shoots proliferated and were maintained on MS (Murashige and Skoog) medium supplemented with 4.4 μM BA. Simultaneous elongation of shoots was obtained in the same medium. Optimum multiplication was observed in cv. LRK-516 (19.7±4.6), in cotyledonary nodes isolated from the adjoining node and cultured individually in 250 ml flasks. This indicates lateral inhibition of adjoining meristems. A positive influence of culture flasks as opposed to test tubes on the proliferation of multiple shoots was observed in all six cultivars tested. The morphogenic response varied with genotype and the nature of explants. Rooting of elongated shoots was achieved on MS medium devoid of growth regulators. The plantlets were transferred to the field after hardening in the greenhouse. All plants flowered and formed bolls on maturity.     

Phytochemical Profiling and Pharmacological Evaluation of Leaf Extracts of Ruellia tuberosa L.: An In Vitro and In Silico Approach

The present study was designed to appraise the photoprotective, antioxidant, and antibacterial bioactivities of Ruellia tuberosa leaves extracts (RtPE, RtChl, RtEA, RtAc, RtMe, and RtHMe). The results showed that, RtHMe extracts of R. tuberosa was rich in total phenolic content, i. e., 1.60 mgGAE/g dry extract, while highest total flavonoid content was found in RtAc extract, i. e., 0.40 mgQE/g. RtMe showed effective antioxidant activity (%RSA: 58.16) at the concentration of 120 μL. RtMe, RtEA and RtHMe exhibited effective in vitro antibacterial activity against Gram-negative bacteria (E. coli). In silico docking studies revealed that paucifloside (−11.743 kcal/mol), indole-3-carboxaldehyde (−7.519 kcal/mol), nuomioside (−7.275 kcal/mol), isocassifolioside (−6.992 kcal/mol) showed best docking score against PDB ID 2EX8 [penicillin binding protein 4 (dacB) from Escherichia coli, complexed with penicillin-G], PDB ID 6CQA (E. coli dihydrofolate reductase protein complexed with inhibitor AMPQD), PDB ID 2Y2I [Penicillin-binding protein 1B in complex with an alkyl boronate (ZA3)] and PDB ID 2OLV (from S. aureus), respectively. Docked phytochemicals also showed good drug likeness properties.     

Central Role for MCP-1/CCL2 in Injury-Induced Inflammation Revealed by In Vitro,In Silico,and Clinical Studies

The translation of in vitro findings to clinical outcomes is often elusive. Trauma/hemorrhagic shock (T/HS) results in hepatic hypoxia that drives inflammation. We hypothesize that in silico methods would help bridge in vitro hepatocyte data and clinical T/HS, in which the liver is a primary site of inflammation. Primary mouse hepatocytes were cultured under hypoxia (1% O₂) or normoxia (21% O₂) for 1–72 h, and both the cell supernatants and protein lysates were assayed for 18 inflammatory mediators by Luminex™ technology. Statistical analysis and data-driven modeling were employed to characterize the main components of the cellular response. Statistical analyses, hierarchical and k-means clustering, Principal Component Analysis, and Dynamic Network Analysis suggested MCP-1/CCL2 and IL-1α as central coordinators of hepatocyte-mediated inflammation in C57BL/6 mouse hepatocytes. Hepatocytes from MCP-1-null mice had altered dynamic inflammatory networks. Circulating MCP-1 levels segregated human T/HS survivors from non-survivors. Furthermore, T/HS survivors with elevated early levels of plasma MCP-1 post-injury had longer total lengths of stay, longer intensive care unit lengths of stay, and prolonged requirement for mechanical ventilation vs. those with low plasma MCP-1. This study identifies MCP-1 as a main driver of the response of hepatocytes in vitro and as a biomarker for clinical outcomes in T/HS, and suggests an experimental and computational framework for discovery of novel clinical biomarkers in inflammatory diseases.     

Evaluation of Cotton Leaf Curl Virus Resistance in BC1, BC2, and BC3 Progenies from an Interspecific Cross between Gossypium arboreum and Gossypium hirsutum

Cotton leaf curl virus disease (CLCuD) is an important constraint to cotton production. The resistance of G. arboreum to this devastating disease is well documented. In the present investigation, we explored the possibility of transferring genes for resistance to CLCuD from G. arboreum (2n = 26) cv 15-Mollisoni into G. hirsutum (2n = 52) cv CRSM-38 through conventional breeding. We investigated the cytology of the BC₁ to BC₃ progenies of direct and reciprocal crosses of G. arboreum and G. hirsutum and evaluated their resistance to CLCuD. The F₁ progenies were completely resistant to this disease, while a decrease in resistance was observed in all backcross generations. As backcrossing progressed, the disease incidence increased in BC₁ (1.7–2.0%), BC₂ (1.8–4.0%), and BC₃ (4.2–7.0%). However, the disease incidence was much lower than that of the check variety CIM-496, with a CLCuD incidence of 96%. Additionally, the disease incidence percentage was lower in the direct cross 2(G. arboreum)×G. hirsutum than in that of G. hirsutum×G. arboreum. Phenotypic resemblance of BC₁ ∼BC₃ progenies to G. arboreum confirmed the success of cross between the two species. Cytological studies of CLCuD-resistant plants revealed that the frequency of univalents and multivalents was high in BC₁, with sterile or partially fertile plants, but low in BC₂ (in both combinations), with shy bearing plants. In BC₃, most of the plants exhibited normal bearing ability due to the high frequency of chromosome associations (bivalents). The assessment of CLCuD through grafting showed that the BC₁ to BC₃ progenies were highly resistant to this disease. Thus, this study successfully demonstrates the possibility of introgressing CLCuD resistance genes from G. arboreum to G. hirsutum.     

The REDUCED LEAFLET Genes Encode Key Components of the trans-Acting Small Interfering RNA Pathway and Regulate Compound Leaf and Flower Development in Lotus japonicus

The endogenous trans-acting small interfering RNA (ta-siRNA) pathway plays a conserved role in adaxial-abaxial patterning of lateral organs in simple-leafed plant species. However, its function in compound-leafed species is largely unknown. Using the compound-leafed species Lotus japonicus, we identified and characterized two independent mutants, reduced leaflet1 (rel1) and rel3, whose most conspicuous defects in compound leaves are abaxialized leaflets and reduction in leaflet number. Concurrent mutations in REL genes also compromise flower development and result in radial symmetric floral organs. Positional cloning revealed that REL1 and REL3 encode the homologs of Arabidopsis (Arabidopsis thaliana) SUPPRESSOR OF GENE SILENCING3 and ARGONAUTE7/ZIPPY, respectively, which are key components of the ta-siRNA pathway. These observations, together with the expression and functional data, demonstrated that the ta-siRNA pathway plays conserved yet distinct roles in the control of compound leaf and flower development in L. japonicus. Moreover, the phenotypic alterations of lateral organs in ta-siRNA-deficient mutants and the regulation of downstream targets by the ta-siRNA pathway in L. japonicus were similar to those in the monocots but different from Arabidopsis, indicating many parallels between L. japonicus and the monocots in the control of lateral organ development by the ta-siRNA pathway.Plant endogenous small RNAs can be categorized into microRNAs (miRNAs) and small interfering RNAs (siRNAs) according to their mechanism of biogenesis (Vaucheret, 2006). trans-Acting siRNAs (ta-siRNAs) are one type of siRNA, and their biogenesis requires several key components, such as SUPPRESSOR OF GENE SILENCING3 (SGS3), RNA-DEPENDENT RNA POLYMERASE6 (RDR6), DICER-LIKE4 (DCL4), ARGONAUTE7 (AGO7)/ZIPPY (ZIP), and dsRNA-BINDING4 (Peragine et al., 2004; Vazquez et al., 2004; Gasciolli et al., 2005; Xie et al., 2005; Yoshikawa et al., 2005; Adenot et al., 2006; Nakazawa et al., 2007). Recent studies revealed that the ta-siRNA pathway is integrated into different processes of plant development, such as vegetative phase transition in Arabidopsis (Arabidopsis thaliana; Hunter et al., 2003; Peragine et al., 2004; Xie et al., 2005; Nakazawa et al., 2007) and shoot apical meristem (SAM) initiation in rice (Oryza sativa; Satoh et al., 1999; Itoh et al., 2000; Nagasaki et al., 2007). Parallel studies of this pathway in simple-leafed species also showed that the ta-siRNA pathway plays critical roles in patterning of leaves and floral organs.In flowering plants, leaves and flowers are produced on the periphery of the apical meristem. These lateral organs are structurally asymmetric with regard to the apical meristem. The adaxial side is adjacent to the meristem, while the abaxial side is away from the meristem. The ta-siRNA pathway was found to play a conserved role in specifying the adaxial identity of lateral organs in both monocots and dicots, but defects in the ta-siRNA pathway caused more severe phenotypes in monocots than in dicot Arabidopsis. In Arabidopsis, no clear leaf polarity defects were detected in the ta-siRNA-defective mutants. However, blocking the ta-siRNA pathway in asymmetric1 (as1) or as2 background, which are regulators of leaf adaxial identity (Lin et al., 2003; Xu et al., 2003), results in enhanced adaxial-abaxial leaf defects (Li et al., 2005; Xu et al., 2006; Garcia et al., 2006). In addition, the as2rdr6 double mutants also display aberrant flowers with sepals failing to enwrap the inner whorl organs and some sepals and petals becoming needle-like structures (Li et al., 2005). In maize (Zea mays), mutations in LEAFBLADELESS1 (LBL1), which encodes the Arabidopsis SGS3 ortholog, give rise to abnormal leaves with partial or complete loss of adaxial cell identity (Timmermans et al., 1998; Nogueira et al., 2007). In severe lbl1 mutants, leaf-like lateral organs of inflorescences and flowers develop as symmetric, thread-like organs, and the immature ear is exposed and arrested in development (Timmermans et al., 1998). In rice, the osdcl4-1 mutants display an abaxialized epidermis in coleoptiles and in the first leaf, and knockdown of OsDCL4 can lead to the awn-like lemma with a radial abaxialized identity and the stamens and carpel not enwrapped by the lemma and pelea (Liu et al., 2007). Transgenic rice plants with ectopic expression of SHOOTLESS4 (SHL4), the homolog of Arabidopsis AGO7, exhibit partially adaxialized leaves (Nagasaki et al., 2007; Shi et al., 2007).In addition to the ta-siRNA pathway, other components have also been shown to be involved in the adaxial-abaxial patterning of lateral organs. The Antirrhinum majus PHANTASTICA (PHAN) gene (Waites et al., 1998; Byrne et al., 2000; Xu et al., 2003; Qi et al., 2004), which is the ortholog of Arabidopsis AS1, and CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) gene family members (McConnell et al., 2001; Emery et al., 2003) contribute to adaxial pattern formation of lateral organs, whereas members of YABBY (YAB; Sawa et al., 1999; Siegfried et al., 1999) and KANADI (Eshed et al., 2001; Kerstetter et al., 2001) gene families, AUXIN RESPONSE FACTOR3 (ARF3) and ARF4 (Pekker et al., 2005), and the miRNAs miR165/166 (Emery et al., 2003; Eshed et al., 2004; Mallory et al., 2004) are required for specifying abaxial identity. How the activities of these adaxial and abaxial determinants are coordinated has been extensively studied. It was found that ARF3 and ARF4 are regulated by the TAS3 ta-siRNA, and this regulation is conserved in both monocots and dicots (Allen et al., 2005; Williams et al., 2005). Recent studies in Arabidopsis suggest that ta-siRNAs act in a non-cell-autonomous manner to spatially restrict ARF activity (Chitwood et al., 2009; Schwab et al., 2009).In contrast to simple leaves with their single lamina, compound leaves are composed of one petiole and several leaflets. It is found that genes required for the adaxial-abaxial patterning of lateral organs in simple-leafed species also play critical roles in compound-leafed species, but these genes play multiple roles in compound leaf development. In tomato (Solanum lycopersicum), down-regulation of PHAN ortholog disturbs the leaf polarity as well as leaflet formation (Kim et al., 2003). Extensive studies of the PHAN expression in diverse compound-leafed species suggest that the function of PHAN in maintaining leaf adaxial identity is associated with leaflet formation in compound leaves and reduced adaxial identity of leaf primordia by down-regulation of PHAN could change pinnate compound leaves into palmate leaves (Kim et al., 2003). In pea (Pisum sativum), the role of PHAN in compound leaf development has also been elucidated by characterization of the phan mutant crispa (cri; Tattersall et al., 2005). However, unlike antisense PHAN transgenic tomato leaves, the cri mutant has the individual leaflet abaxialized, rather than the whole leaf. The number of lateral organs on the cri mutant compound leaves, including leaflets, is not altered, and the leaves remain pinnate. Apart from leaf development, the cri mutation also affects flower development. Although the floral organ identity and organ number are not altered, the laminar floral organ display abaxialized identity (Tattersall et al., 2005).The ta-siRNA pathway plays a critical role in simple-leafed species, but its role in compound-leafed species is not understood. Here, we address this question by analyzing loss-of-function reduced leaflet (rel1) and rel3 mutants in the compound-leafed species Lotus japonicus. Phenotypic characterization shows compound leaves of rel mutants exhibit a conspicuous disturbance in leaflet polarity as well as reduction in leaflet number. Besides the abnormal compound leaves, flower development is also severely affected in rel mutants, showing radial symmetric petals. REL1 and REL3 were identified by map-based cloning and were shown to be homologs of Arabidopsis SGS3 and AGO7, respectively. REL1 and REL3 act in the same genetic pathway and are both required for the biogenesis of TAS3 ta-siRNA. Further investigation reveals that the homolog of the Arabidopsis ARF3 is duplicated in the L. japonicus genome and that the duplicate ARF3 homologs and the ARF4 homolog are all negatively regulated by the ta-siRNA pathway. Furthermore, we found that the expression of LjYAB1, a homolog of Arabidopsis YAB1, was decreased in rel mutants, which may be associated with the reduced lamina.Taken together, our data reveal that the ta-siRNA pathway is integrated into the regulatory networks in the control of lateral organ development in L. japonicus and further emphasize the importance of the ta-siRNA pathway in compound leaf development. Moreover, our results also indicate many parallels between L. japonicus and monocots for the ta-siRNA pathway in the regulation of lateral organs.     

Comparative Epidermal Ultrastructure of Cotton (Gossypium hirsutum L.) Leaf, Bract and Capsule Wall

Cotton leaves are more physiologically active than the bractand the capsule wall of the fruiting structures. To elucidatethe disparities in their physiological behaviour, epidermalcell density, stomatal index, stomatal size, trichome densityand type, and epicuticular wax ultrastructure of cotton leaf,bract and capsule wall were delineated using scanning electronmicroscopy (SEM). The epidermal cells of the outer periclinalwalls on both surfaces of the leaf and bract were raised andconvex. Conversely, the capsule wall epidermal cells were polygonalwith flat outer periclinal walls. The stomatal complex in theleaf and bract was paracytic, whereas in the capsule wall thestomatal complex was anomocytic. The adaxial and abaxial stomataof the leaf were coplanar to the epidermal surface, as opposedto the raised adaxial stomata on the bract. On the contrary,the stomata on the capsule wall surface appeared to be slightlysunken. Furthermore, the capsule wall stomata were larger thanthe stomata on either surface of both the leaf and the bract.The stomatal index was greater on the abaxial surfaces of theleaf and the bract (18.4 and 9.4, respectively) than their correspondingadaxial surfaces (14.4 and 4.7, respectively). Leaves had thehighest stomatal index followed by the bract and the capsulewall. The indumentum consisted of glandular and nonglandulartrichomes, the density of which was greater on the abaxial surfacesthan on the adaxial surfaces of the leaf and bract. The capsulewall indumentum lacked nonglandular trichomes. Epicuticularwax occurred in the form of striations. However, the striationpattern varied among the organs. This study clearly illustratesmorphological disparities in the epidermal features of leaf,bract and capsule wall, helping to explain their physiologicaldivergence. Copyright 2000 Annals of Botany Company Gossypium hirsutum, epicuticular wax, raised stomata, scanning electron microscopy, stomatal index, trichomes     

Effects of Guaianolide derivative I on fibre initiation and elongation in Gossypium arboreum L. in relation to adverse effects of cool temperature

Cotton ovules collected during late September with prevalent night cool temperature (15°C), cultured at 30°C/15°C i.e. cycling temperatures in Beasley and Ting medium had very few epidermal cells showing bulging. Supplementing cultures with guaianolide derivative I (E-13 methyldehydrocostus lactone) promoted fibre initiation. At—1 day preanthesis (DPA), IAA oxidase activity declined in guaianolide-treated cultures but increased during the elongation phase and was enhanced during the secondary wall thickening phase. However, o-diphenol oxidase activity was adversely affected during the fibre initiation phase. The activities of all the other enzymes studied viz. acid invertase, phenylalanine ammonia lyase, -glucosidase and IAA oxidase increased, except -galactosidase, during the later phase in comparison with the controls. The present study indicates that guaianolide derivative I triggers early initiation and promotes fibre elongation by regulatin o-diphenols and IAA-oxidation levels, which in turn check wall loosening. Considerable enhancement in the soluble acid invertase activity by this compound suggests its role in apoplastic sucrose hydrolysis, thereby preventing its accumulation.Abbreviations DPA days pre anthesis - DAC days after culturing - DAA days after anthesis     

Development of chromosome-specific markers with high polymorphism for allotetraploid cotton based on genome-wide characterization of simple sequence repeats in diploid cottons (Gossypium arboreum L. and Gossypium raimondii Ulbrich)

Background

Tetraploid cotton contains two sets of homologous chromosomes, the At- and Dt-subgenomes. Consequently, many markers in cotton were mapped to multiple positions during linkage genetic map construction, posing a challenge to anchoring linkage groups and mapping economically-important genes to particular chromosomes. Chromosome-specific markers could solve this problem. Recently, the genomes of two diploid species were sequenced whose progenitors were putative contributors of the At- and Dt-subgenomes to tetraploid cotton. These sequences provide a powerful tool for developing chromosome-specific markers given the high level of synteny among tetraploid and diploid cotton genomes. In this study, simple sequence repeats (SSRs) on each chromosome in the two diploid genomes were characterized. Chromosome-specific SSRs were developed by comparative analysis and proved to distinguish chromosomes.

Results

A total of 200,744 and 142,409 SSRs were detected on the 13 chromosomes of Gossypium arboreum L. and Gossypium raimondii Ulbrich, respectively. Chromosome-specific SSRs were obtained by comparing SSR flanking sequences from each chromosome with those from the other 25 chromosomes. The average was 7,996 per chromosome. To confirm their chromosome specificity, these SSRs were used to distinguish two homologous chromosomes in tetraploid cotton through linkage group construction. The chromosome-specific SSRs and previously-reported chromosome markers were grouped together, and no marker mapped to another homologous chromosome, proving that the chromosome-specific SSRs were unique and could distinguish homologous chromosomes in tetraploid cotton. Because longer dinucleotide AT-rich repeats were the most polymorphic in previous reports, the SSRs on each chromosome were sorted by motif type and repeat length for convenient selection. The primer sequences of all chromosome-specific SSRs were also made publicly available.

Conclusion

Chromosome-specific SSRs are efficient tools for chromosome identification by anchoring linkage groups to particular chromosomes during genetic mapping and are especially useful in mapping of qualitative-trait genes or quantitative trait loci with just a few markers. The SSRs reported here will facilitate a number of genetic and genomic studies in cotton, including construction of high-density genetic maps, positional gene cloning, fingerprinting, and genetic diversity and comparative evolutionary analyses among Gossypium species.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1265-2) contains supplementary material, which is available to authorized users.     

An In Silico Analysis of the Binding Modes and Binding Affinities of Small Molecule Modulators of PDZ-Peptide Interactions

Inhibitors of PDZ-peptide interactions have important implications in a variety of biological processes including treatment of cancer and Parkinson’s disease. Even though experimental studies have reported characterization of peptidomimetic inhibitors of PDZ-peptide interactions, the binding modes for most of them have not been characterized by structural studies. In this study we have attempted to understand the structural basis of the small molecule-PDZ interactions by in silico analysis of the binding modes and binding affinities of a set of 38 small molecules with known K_i or K_d values for PDZ2 and PDZ3 domains of PSD-95 protein. These two PDZ domains show differential selectivity for these compounds despite having a high degree of sequence similarity and almost identical peptide binding pockets. Optimum binding modes for these ligands for PDZ2 and PDZ3 domains were identified by using a novel combination of semi-flexible docking and explicit solvent molecular dynamics (MD) simulations. Analysis of the binding modes revealed most of the peptidomimectic ligands which had high K_i or K_d moved away from the peptide binding pocket, while ligands with high binding affinities remained in the peptide binding pocket. The differential specificities of the PDZ2 and PDZ3 domains primarily arise from differences in the conformation of the loop connecting βB and βC strands, because this loop interacts with the N-terminal chemical moieties of the ligands. We have also computed the MM/PBSA binding free energy values for these 38 compounds with both the PDZ domains from multiple 5 ns MD trajectories on each complex i.e. a total of 228 MD trajectories of 5 ns length each. Interestingly, computational binding free energies show good agreement with experimental binding free energies with a correlation coefficient of approximately 0.6. Thus our study demonstrates that combined use of docking and MD simulations can help in identification of potent inhibitors of PDZ-peptide complexes.     

Functional Analysis and RNA Sequencing Indicate the Regulatory Role of Argonaute1 in Tomato Compound Leaf Development

Regardless of whether a leaf is simple or compound, the mechanism underlying its development will give rise to a full comprehension of plant morphogenesis. The role of Argonaute1 (AGO1) in the development of simple leaves has been established, but its role in the development of compound leaves remains to be characterized. In this paper, a virus-induced gene silencing (VIGS) strategy was used to dramatically down-regulate the expression of AGO1 ortholog in tomatoes, a model plant for research into compound leaves. AGO1-silenced tomato compound leaves exhibited morphological defects of leaf adaxial-abaxial and trichome development. Analysis of global gene expression profiles indicated that the silencing of AGO1 in tomato compound leaf caused significant changes in the expression of several critical genes, including Auxin Response Factor 4 (ARF4) and Non-expressor of PR5 (NPR5), which were involved in adaxial-abaxial formation and IAA15 that was found to contribute to growth of trichomes as well as Gibberellic Acid Insensitive (GAI) which participated in hormone regulation. Collectively, these results shed light on the complicated mechanism by which AGO1 regulates compound leaf development.     

棉花咖啡酰辅酶A-O-甲基转移酶基因的克隆及表达

根据棉花纤维特异表达cDNA文库分析得到的咖啡酰辅酶A-O-甲基转移酶(CCoAOMT)基因EST序列设计引物,采用RT-PCR技术首次从棉花中克隆了一个CCoAOMT基因,命名为GhCCoAOMT1(GenBank登录号为FJ848871).研究结果表明:GhCCoAOMT1基因cDNA全长960 bp,具有一个753 bp的开放阅读框,5'非编码区为9 bp,3'非编码区为198 bp,编码250个氨基酸,预测分子量约为28.306 kDa,等电点为5.39.利用PCR方法克隆了GhCCoAOMT1基因的基因组序列,长度为1 311 bp,包含5个外显子和4个内含子.氨基酸同源性分析发现,GhCCoAOMT1与来自毛白杨、烟草和苎麻的CCoAOMT同源性较高.半定量RT-PCR检测表明,GhCCoAOMT1基因在棉花各个组织中都有表达,其中茎部的表达量最高,其次表达量依次为根>花瓣>子叶>10 d纤维>雄蕊>胚珠>叶.