Efficient Transformation Technique Research Articles

Exploiting Brassica rapa L. subsp. pekinensis Genome Research

Chinese cabbage, Brassica rapa L. subsp. pekinensis is a crucial and extensively consumed vegetable in the world, especially Eastern Asia. The market demand for this leafy vegetable increases year by year, resulting in multiple challenges for agricultural researchers worldwide. Multi-omic approaches and the integration of functional genomics helps us understand the relationships between Chinese cabbage genomes and phenotypes under specific physiological and environmental conditions. However, challenges exist in integrating multi-omics for the functional analysis of genes and for developing potential traits for Chinese cabbage improvement. However, the panomics platform allows for the integration of complex omics, enhancing our understanding of molecular regulator networks in Chinese cabbage agricultural traits. In addition, the agronomic features of Chinese cabbage are significantly impacted by the environment. The expression of these agricultural features is tightly regulated by a combination of signals from both the internal regulatory network and the external growth environment. To comprehend the molecular process of these characteristics, it is necessary to have a prior understanding of molecular breeding for the objective of enhancing quality. While the use of various approaches in Chinese cabbage is still in its early stages, recent research has shown that it has the potential to uncover new regulators both rapidly and effectively, leading to updated regulatory networks. In addition, the utilization of the efficient transformation technique in conjunction with gene editing using CRISPR/Cas9 will result in a reduction in time requirements and facilitate a more precise understanding of the role of the regulators. Numerous studies about Chinese cabbage have been conducted in the past two decades, but a comprehensive review about its genome still limited. This review provides a concise summary of the latest discoveries in genomic research related to Brassica and explores the potential future developments for this species.

Highly efficient transformation of the model zygnematophycean alga Closterium peracerosum-strigosum-littorale complex by square-pulse electroporation.

The zygnematophycean algae occupy an important phylogenetic position as the closest living relatives of land plants. Reverse genetics is quite useful for dissecting the functions of genes. However, this strategy requires genetic transformation, and there are only a few reports of successful transformation in zygnematophycean algae. Here, we established a simple and highly efficient transformation technique for the unicellular zygnematophycean alga Closterium peracerosum-strigosum-littorale complex using a square electric pulse-generating electroporator without the need for cell wall removal. Using this method, the transformation efficiency increased > 100-fold compared with our previous study using particle bombardment. We also succeeded in performing CRISPR/Cas9-based gene knockout using this new method. Our method requires only small amounts of labor, time and incubator space. Moreover, our technique could also be utilized to transform other charophycean algae with available genome information by optimizing the electric pulse conditions.

Development of an efficient root transgenic system for pigeon pea and its application to other important economically plants.

SummaryFor non‐model plants, functional characterization of genes is still hampered by lack of efficient stable transformation procedures. Here, we report a simple, fast and efficient transformation technique with Agrobacterium rhizogenes for generating stable transgenic roots in living plants to facilitate functional studies in vivo. We showed that injection of A. rhizogenes into stems of various plant species lead to stable transgenic root generation, which can sustain plant growth after the original, non‐transgenic roots were cut off. A transformation system was established for pigeon pea, a major woody food crop, after optimizing the selection of A. rhizogenes strains, bacterium concentration, injection position and seedling age. RT‐PCR and fluorescence observation indicated a transgenic root induction efficiency of about 39% in pigeon pea. Furthermore, induction of hairy roots was achieved in nine out of twelve tested economically important plants at an efficiency of 15–39%. As proof of concept, bimolecular fluorescence complementation (BiFC) assay was applied to test the interaction between CcCIPK14 and CcCBL1/2 in pigeon pea. Additionally, ectopic expression of the bZIP transcription factor MdHY5 from apple confirmed the utility of the transformation technique for engineering anthocyanin synthesis in roots. Taken together, we show that this method allows fast in vivo studies of gene function in a wide range of plant species.

Efficient transformations for Klee's measure problem in the streaming model

Given a stream of rectangles over a discrete space, we consider the problem of computing the total number of distinct points covered by the rectangles. This is the discrete version of the two-dimensional Klee's measure problem for streaming inputs. Given 0<ϵ,δ<1, we provide (ϵ,δ)-approximations for bounded side length rectangles and for bounded aspect ratio rectangles. For the case of arbitrary rectangles, we provide an O(log⁡U)-approximation, where U is the total number of discrete points in the two-dimensional space. The time to process each rectangle and the total required space are polylogarithmic in U. The time to answer a query for the total area is constant. We construct efficient transformation techniques that project rectangle areas to one-dimensional ranges and then use a streaming algorithm for the one-dimensional Klee's measure problem to obtain these approximations. The projections are deterministic, and to our knowledge, these are the first approaches of this kind that provide efficiency and accuracy trade-offs in the streaming model.

ELECTROMAGNETIC FIELD TRANSFORMATIONS FOR MEASUREMENTS AND SIMULATIONS (Invited Paper)

Electromagnetic field transformations are important for electromagnetic simulations and for measurements. Especially for field measurements, the influence of the measurement probe must be considered, and this can be achieved by working with weighted field transformations. This paper is a review paper on weighted field transformations, where new information on algorithmic properties and new results are also included. Starting from the spatial domain weighted radiation integral involving free space Green's functions, properties such as uniqueness and the meaning of the weighting function are discussed. Several spectral domain formulations of the weighted field transformation integrals are reviewed. The focus of the paper is on hierarchical multilevel representations of irregular field transformations with propagating plane waves on the Ewald sphere. The resulting Fast Irregular Antenna Field Transformation Algorithm (FIAFTA) is a versatile and efficient transformation technique for arbitrary antenna and scattering fields. The fields can be sampled at arbitrary irregular locations and with arbitrary measurement probes without compromising the accuracy and the efficiency of the algorithm. FIAFTA supports different equivalent sources representations of the radiation or scattering object: 1) equivalent surface current densities discretized on triangular meshes, 2) plane wave representations, 3) spherical harmonics representations. The current densities provide for excellent spatial localization and deliver most diagnostics information about the test object. A priori information about the test object can easily be incorporated, too. Using plane wave and spherical harmonics representations, the spatial localization is not as good as with spatial current densities, but still much better than in the case of conventional modal expansions. Both far-field based expansions lead to faster transformations than the equivalent currents and in particular the orthogonal spherical harmonics expansion is a very attractive and robust choice. All three expansions are well-suited for efficient echo suppression by spatial filtering. Various new field transformation and new computational performance results are shown in order to illustrate some capabilities of the algorithm.

An Efficient Transformation Technique for the Direct Recovering of the Antenna Far-Field Pattern from Near-Field Measurements Collected along a Helix

A near-field to far-field transformation technique with helicoidal scanning for elongated antennas, which allows the evaluation of the antenna far-field pattern in any cut plane directly from a nonredundant number of near-field data without interpolating them, is developed in this paper. It is based on the nonredundant sampling representations of electromagnetic fields and employs a flexible source modelling suitable for long antennas to determine the number of helix turns. The number of near-field measurements on each turn is on the contrary dictated by the minimum cylinder rule, as in the classical cylindrical scanning, in order to reduce the computational burden and to simplify the scanning from the mechanical viewpoint. Some numerical and experimental results assessing the effectiveness of the proposed technique are reported.

Barley Genomics: An Overview

Barley (Hordeum vulgare), first domesticated in the Near East, is a well-studied crop in terms of genetics, genomics, and breeding and qualifies as a model plant for Triticeae research. Recent advances made in barley genomics mainly include the following: (i) rapid accumulation of EST sequence data, (ii) growing number of studies on transcriptome, proteome, and metabolome, (iii) new modeling techniques, (iv) availability of genome-wide knockout collections as well as efficient transformation techniques, and (v) the recently started genome sequencing effort. These developments pave the way for a comprehensive functional analysis and understanding of gene expression networks linked to agronomically important traits. Here, we selectively review important technological developments in barley genomics and related fields and discuss the relevance for understanding genotype-phenotype relationships by using approaches such as genetical genomics and association studies. High-throughput genotyping platforms that have recently become available will allow the construction of high-density genetic maps that will further promote marker-assisted selection as well as physical map construction. Systems biology approaches will further enhance our knowledge and largely increase our abilities to design refined breeding strategies on the basis of detailed molecular physiological knowledge.

Genetic transformation technology: Status and problems

Transfer of genes from heterologous species provides the means of selectively introducing new traits into crop plants and expanding the gene pool beyond what has been available to traditional breeding systems. With the recent advances in genetic engineering of plants, it is now feasible to introduce into crop plants, genes that have previously been inaccessible to the conventional plant breeder, or which did not exist in the crop of interest. This holds a tremendous potential for the genetic enhancement of important food crops. However, the availability of efficient transformation methods to introduce foreign DNA can be a substantial barrier to the application of recombinant DNA methods in some crop plants. Despite significant advances over the past decades, development of efficient transformation methods can take many years of painstaking research. The major components for the development of transgenic plants include the development of reliable tissue culture regeneration systems, preparation of gene constructs and efficient transformation techniques for the introduction of genes into the crop plants, recovery and multiplication of transgenic plants, molecular and genetic characterization of transgenic plants for stable and efficient gene expression, transfer of genes to elite cultivars by conventional breeding methods if required, and the evaluation of transgenic plants for their effectiveness in alleviating the biotic and abiotic stresses without being an environmental biohazard. Amongst these, protocols for the introduction of genes, including the efficient regeneration of shoots in tissue cultures, and transformation methods can be major bottlenecks to the application of genetic transformation technology. Some of the key constraints in transformation procedures and possible solutions for safe development and deployment of transgenic plants for crop improvement are discussed.

An Extended Sigmoidal Transformation Technique for Evaluating Weakly Singular Integrals without Splitting the Integration Interval

In this paper, we present an efficient transformation technique for accurate numerical evaluation of weakly singular integrals with interior singularities. The present transformation technique does not require any division of the integration interval. It is composed of two parts of a sigmoidal transformation whose tails coincide with a singular point smoothly up to the order of the sigmoidal transformation employed. Therefore, in using the standard Gauss quadrature rule, the present transformation has a feature in which the integration points are clustered into the interior singular point very closely, as in the case of endpoint singular integrals. The results of some numerical examples show the superiority of the present method over the existing methods.

Introduction of exogenous DNA into cotton via the pollen-tube pathway with GFP as a reporter

The green fluorescent protein (GFP) gene from the jellyfish Aequorea victoria as a vital reporter for gene expression in plants is considered to have several advantages over other reporter genes. The pBIN35S-mGFP4 plasmid DNA has been introduced into cotton embryos by the pollen-tube pathway method. A transformed seedling has been verified according to its GFP-related fluorescence and Southern blotting analysis. The results provided direct and convincing facts in cytology and molecular biology for the pollen-tube pathway method, an efficient transformation technique used in plants.

On the status and perspectives of MCDF calculations and measurements of transition data in the Be isoelectronic sequence

Transition energies and rates between the and levels of ions in the Be isoelectronic sequence (nuclear charges Z = 7-28, 30, 36, 42) are calculated in the valence and core-valence limit using the multiconfiguration Dirac-Fock method. The Breit interaction and finite nuclear mass effects are taken into account in subsequent relativistic configuration-interaction calculations. Separately optimized orbital sets are used for the initial and final states in the transitions. The transition matrix elements are evaluated with an efficient transformation technique. The calculated energy separations and transition probabilities are compared with critically evaluated experimental values and with results from other recent calculations.

Accurate multiconfiguration Dirac - Fock calculations of transition probabilities in the Mg isoelectronic sequence

Results from valence and core - valence multiconfiguration Dirac - Fock and relativistic configuration interaction calculations including the Breit interaction are presented for the and transitions (E1, M2) in the Mg isoelectronic sequence. In the calculations the orbital sets of the initial- and final-state wavefunctions were not restricted to be the same, but were optimized independently. The evaluation of the transition matrix elements was done with an efficient transformation technique. The calculated energy separations and transition probabilities are found to be in good agreement with experiment and compare favourably with other recent calculations. For completeness, results for forbidden transitions (E2, M1) within the fine-structure levels are also included.

Numerical solution of periodically pulsed laminar free jets

A LTHOUGH the behavior of a steady, two-dimensional, laminar free jet has been treated in detail by many workers such as Pai and Schlichting, there is still limited information on the flow development region near the nozzle exit, the effect of exit conditions on flow characteristics, the location of the virtual origin, and the location at which the velocity profile becomes very nearly self-preserving. Few detailed experimental studies have been reported, mainly because the laminar free jet has limited applications. Numerical solutions have been sought by Pai and Hsieh and Hornbeck. Velocity profiles fluctuating about a mean are common in practice. However, unsteady, two-dimensional, laminar free jets issuing into a stationary medium have scarcely been explored either experimentally or theoretically. This is mainly because unsteady laminar jets normally become turbulent shortly after leaving the nozzle. Closed form solutions always entail certain assumptions which limit their range of validity. For instance, McCormack et al. obtained a closed solution for the mean velocity of a gas jet in the near-field region with a source of periodicity at the orifice by employing the method developed by Lin. However, the solution is only valid for high frequencies. The problem of unsteady mixing of compressible fluid has been studied by Pai with perturbation techniques. Recently, Kent computed the unsteady laminar axisymmetric jet by using an integral method which reduces the number of spatial coordinates from two to one. This greatly reduces computation in terms of space and time but suffers from the drawback that accurate velocity profile information cannot be obtained. The objectives of this study are to use the case of a laminar free jet to develop an efficient transformation technique which is applicable to the computation of unsteady turbulent jets, to study the mean flow development of steady and unsteady laminar free jets, and to examine the unsteady effects.