植物单倍体技术及其应用的研究进展

该文较全面地综述了获得植物单倍体的相关途径及其在基础科学研究和植物育种方面的重要应用,着重介绍了一种基于着丝粒改造的染色体消除法诱导单倍体的策略及植物单倍体在基因组学研究中潜在的应用价值,旨在促进植物单倍体技术的完善并开拓其应用领域。     

Plant transformation technology

Plant transformation has its roots in the research on Agrobacterium that was being undertaken in the early 1980s. The last two decades have seen significant developments in plant transformation technology, such that a large number of transgenic crop plants have now been released for commercial production. Advances in the technology have been due to development of a range of Agrobacterium-mediated and direct DNA delivery techniques, along with appropriate tissue culture techniques for regenerating whole plants from plant cells or tissues in a large number of species. In addition, parallel developments in molecular biology have greatly extended the range of investigations to which plant transformation technology can be applied. Research in plant transformation is concentrating now not so much on the introduction of DNA into plant cells, but rather more on the problems associated with stable integration and reliable expression of the DNA once it has been integrated.     

Evolutionary context for understanding and manipulating plant responses to past, present and future atmospheric [CO2

Variation in atmospheric [CO(2)] is a prominent feature of the environmental history over which vascular plants have evolved. Periods of falling and low [CO(2)] in the palaeo-record appear to have created selective pressure for important adaptations in modern plants. Today, rising [CO(2)] is a key component of anthropogenic global environmental change that will impact plants and the ecosystem goods and services they deliver. Currently, there is limited evidence that natural plant populations have evolved in response to contemporary increases in [CO(2)] in ways that increase plant productivity or fitness, and no evidence for incidental breeding of crop varieties to achieve greater yield enhancement from rising [CO(2)]. Evolutionary responses to elevated [CO(2)] have been studied by applying selection in controlled environments, quantitative genetics and trait-based approaches. Findings to date suggest that adaptive changes in plant traits in response to future [CO(2)] will not be consistently observed across species or environments and will not be large in magnitude compared with physiological and ecological responses to future [CO(2)]. This lack of evidence for strong evolutionary effects of elevated [CO(2)] is surprising, given the large effects of elevated [CO(2)] on plant phenotypes. New studies under more stressful, complex environmental conditions associated with climate change may revise this view. Efforts are underway to engineer plants to: (i) overcome the limitations to photosynthesis from today's [CO(2)] and (ii) benefit maximally from future, greater [CO(2)]. Targets range in scale from manipulating the function of a single enzyme (e.g. Rubisco) to adding metabolic pathways from bacteria as well as engineering the structural and functional components necessary for C(4) photosynthesis into C(3) leaves. Successfully improving plant performance will depend on combining the knowledge of the evolutionary context, cellular basis and physiological integration of plant responses to varying [CO(2)].     

Biostimulants enhance growth and drought tolerance in Arabidopsis thaliana and exhibit chemical priming action

The usage of biostimulants in agriculture has been steadily increasing in recent years, and their benefits have been recognised by growers. The growing interest from industry has led to a boom in the number of products on the market, many of which are derived from a diverse range of sources such as microbials, plant extracts, hydrolysed amino acids and algal extracts. However, there has been a slower recognition of the biostimulant sector by the scientific community. This has been a result of limited fundamental research into the modes of action of many biostimulant products and the speed at which new multi‐compound products have entered the market. In this study, we have developed a readily reproducible bioassay using the model plant Arabidopsis thaliana to test biostimulant efficacy under drought conditions and assess any chemical priming action. We have screened three products with biostimulant action derived from amino acids (Delfan Plus), Ascophyllum nodosum extract (Phylgreen) or potassium phosphite (Trafos K). Under a progressive soil drought condition, we measured changes in plant growth, biochemical content and gene expression levels. Our results demonstrated biostimulant‐mediated drought tolerance, with the products requiring different application timings for successful stress mitigation. The analysis of the biochemical and gene expression changes provided evidence of chemical priming action when plants were pre‐treated with biostimulants prior to the drought stress exposure.     

Quantification by ELISA of Cytokinins in Root-Pressure Exudates of Urtica dioica Plants Grown under Different Nitrogen Levels

ELISAs for [9R]iP, [9R]Z and (diH) [9R]Z have been worked out which, in combination with HPLC., allow the quantitative determination of cytokinins of the isopentenyladenin-, zeatin- and dihydrozeatin-type in samples of plant material. The three ELISAs are optimally applicable in the range from 0.5 to 20 pmoles of cytokinins per assay but reliable measurements can still be performed down to 0.05 pmoles. The assay has been applied to root pressure exudates obtained from Urtica dioica plants grown under controlled conditions and at different nitrogen (nitrate) levels. The predominant cytokinins of the xylem exudate were Z, Z-nucleotide, iP, [9R]iP and iP-nucleotide, while (diH)Z was present to a minor extent. The concentrations of these compounds were found to range between 0.2 and 3 pmoles per ml exudate. Interestingly, no effect of the different nitrogen nutrition on the pattern and concentration of cytokinins in the xylem exudate could be established.     

Phytoserotonin: A review

Serotonin (5-hydroxytryptamine; SER) is one of the well-studied indoleamine neurotransmitters in vertebrates. Recently SER has also been reported in wide range of plant species. The precise function of SER at the physiological level, particularly growth regulation, flowering, xylem sap exudation, ion permeability and plant morphogenesis in plant system has not been clear. Though SER is found in different parts of plant species including leaves, stems, roots, fruits and seeds, the quantity of SER within plant tissues varies widely. SER has been recently shown as a plant hormone in view of its auxin-like activity. This brief review provides an overview of SER biosynthesis, localization, its role in plant morphogenesis and possible physiological functions in plants. This would certainly help to elucidate further the multiple roles of SER in plant morphogenesis. In the future it may form the basis for studies on involvement of SER in cellular signaling mechanisms in plants. Apart from these gaps in understanding the role of SER in ontogeny of plant physiology and ecological, adaptations have been emphasized. Thus, overall perspectives in this area of research and its possible implications have been presented.Key words: biosynthesis, growth regulation, occurrence, physiological functions, phytoserotonin, plant morphogenesis, serotonin     

The relationships of vascular plants

Recent phylogenetic research indicates that vascular plants evolved from bryophyte-like ancestors and that this involved extensive modifications to the life cycle. These conclusions are supported by a range of systematic data, including gene sequences, as well as evidence from comparative morphology and the fossil record. Within vascular plants, there is compelling evidence for two major clades, which have been termed lycophytes (clubmosses) and euphyllophytes (seed plants, ferns, horsetails). The implications of recent phylogenetic work are discussed with reference to life cycle evolution and the interpretation of stratigraphic inconsistencies in the early fossil record of land plants. Life cycles are shown to have passed through an isomorphic phase in the early stages of vascular plant evolution. Thus, the gametophyte generation of all living vascular plants is the product of massive morphological reduction. Phylogenetic research corroborates earlier suggestions of a major representational bias in the early fossil record. Mega-fossils document a sequence of appearance of groups that is at odds with that predicted by cladogram topology. It is argued here that the pattern of appearance and diversification of plant megafossils owes more to changing geological conditions than to rapid biological diversification.     

植物嫁接诱导的遗传变异机理的研究进展

植物嫁接诱导的可遗传变异是一种普遍存在的现象,但是关于嫁接变异产生的条件及机制一直是国内外备受争议的研究课题之一。近年来,对于砧穗之间遗传物质的水平转移方面的研究取得了很大的进步。研究表明在嫁接植物体中,来自砧木的遗传信号物质能够通过胞间连丝和维管束转移到接穗中并调控接穗的生长发育模式。而且,一些非编码RNA还能通过表观遗传修饰改变植物的特性以应对嫁接冲击。文章主要从嫁接遗传变异的产生和维持机制两方面对最新的研究进展进行了系统地综述,这对于深入理解嫁接变异的机理具有一定意义。     

植物Ⅲ型聚酮合酶的分子机制与应用前景

植物III型聚酮合酶能催化生成一系列结构各异、具有不同生理活性、包含查耳酮合酶基本骨架的植物次生代谢产物,这类次生代谢产物不仅使植物体本身的抗逆性提高,并且对人类健康医疗有很好的应用前景。以下综述了近年来从植物中克隆、鉴定III型聚酮合酶的研究进展,着重论述了其分子结构、催化反应的类型和机制、表达调控及其在转基因工程方面的研究和应用前景。这些研究将为有效地对其进行基因改造,合成一些难以化学合成的新型天然化合物奠定基础,并且为将来进一步开展III型聚酮合酶的转基因工程提供了参考。     

Plant bioactives for ruminant health and productivity

Plants have been used throughout history for their medicinal properties. This use has often focused on human health but plants have also been, and still are, applied in ethnoveterinary practice and animal health management. In recent times, the use of synthetic chemicals has become prevalent. Public awareness of the potential environmental and health risks associated with heavy chemical use has also increased. This has put pressure on regulatory bodies to reduce the use of chemicals in agriculture. The most striking example is the 2006 banning of antibiotics in animal feed by the European Union. Moves such as this have increased the drive to find alternatives to synthetic chemicals and research has again turned to the use of plant bioactives as a means of improving animal health. Current scientific evidence suggests there is significant potential to use plants to enhance animal health in general and that of ruminants (cattle, deer, sheep, etc.) in particular. Active areas of research for plant bioactives (particularly saponin and tannin containing plants) include reproductive efficiency, milk and meat quality improvement, foam production/bloat control and methane production. Nematode control is also a significant area of research and the evidence suggests a much broader range of phytochemicals may be effective. This review presents a summary of the literature and examines international research efforts towards the development of plant bioactives for animal health.     

云南鹤庆白依人植物染料的民族植物学研究

植物染料有绿色环保、安全性高等优势,但其资源量少、成本高、色牢度低等缺点限制了植物染料在工业化的应用。云南鹤庆白依人有植物染色的传统习俗,当地有丰富的染料植物资源和传统染色工艺。为调查、记录和研究白依人植物染色和相关传统知识,拓展植物染料资源并促进植物染料的开发利用,该研究对大理州鹤庆县六合彝族乡白依人植物染色及相关传统知识进行了民族植物学调研。2019年9月至2020年3月,对大理州鹤庆县六合彝族乡4个村落的288位信息报告人进行半结构式访谈,对当地植物染料进行实地调研,以参与式观察法记录传统植物染色技艺,通过定量分析法对传统植物染色知识(f值、CII_s值、ICF值)进行分析研究。结果表明:(1)鹤庆白依人使用11种植物染料,分属10科11属。(2)不同地区、年龄、性别的白依人对传统植物染色知识的认知有差异。(3)水红木和密蒙花的使用频率和文化重要性指数较高,并且白依人对蓝染的植物染料认知高度一致。(4)白依人常用植物染料给本民族服饰火草衣染色。该文揭示了鹤庆白依人有较完整的传统植物染色知识体系,但随着时代的发展而逐渐流失。该研究结果为植物染料资源的开发和传统植物染色工艺的研究提供科学线索,促进少数民族植物染料的产业化应用,对少数民族地区的经济发展有重要意义和应用价值。     

红葱种群地上和地下构件的密度制约调节

虽然个体大小和密度的关系是植物生态学研究的中心问题, 但是大多数基础研究只观测植株地上部分的生物量, 即地上部分大小-密度关系, 而对于地下构件大小-密度关系的研究十分薄弱。因为植物个体的生长是构件变化的过程, 所以个体大小和密度的关系不仅表现为种群水平和个体水平, 也表现为构件水平。该文研究了5个密度(36、49、64、121和225株·m^-2)的红葱(Allium cepa var. proliferum)种群地下构件密度制约调节规律及其与地上构件密度制约调节规律的关系, 地下部分和全株(包括地上部分和地下部分)的密度制约调节规律, 及二者与地上部分密度制约调节规律的关系。结果表明: (1)不同密度环境下, 植物的表型可以通过各器官形态的可塑性反应发生调整; 植株地下构件和地上构件的各个特征(株高、叶片长、叶片数、鳞茎直径、分蘖重)均与密度呈显著的线性相关关系; (2)平均根、鳞茎、叶片和鞘生物量均与密度呈显著的幂函数负相关关系, 但异速指数不同: 鳞茎(-1.14)<叶片(-1.03)<根(-0.78)<鞘(-0.49), 表明地下构件的大小和地上构件的大小随密度的变化不一致; (3)平均地下、地上和个体生物量均与种群密度呈显著的幂函数负相关关系, 但异速指数不同, 分别为: -1.13、-0.95和-0.98, 表明地上部分大小和全株大小随种群密度的变化基本一致, 但与地下部分大小的变化不一致。总之, 密度制约对植株地下构件的调节作用大于地上构件, 对地下部分的调节作用大于地上部分, 红葱种群对地下资源的竞争占主导地位。     

Microbial hazards in plant tissue and cell cultures

Summary A wide range of microorganisms (filamentous fungi, yeasts, bacteria, viruses and viroids) and micro-arthropods (mites and thrips) have been identified as contaminants in plant tissue cultures. Contaminant may be introduced with the explant, during manipulations in the laboratory or by micro-arthropod vectors. Contaminants may express themselves immediately or can remain latent for long periods of time. This often makes it difficult to identify the source of contamination. Disinfection protocols have now been developed for a wide range of plant species including those infected with viruses/viroids or endophytic bacteria. They may include the selection of pathogen-free donor plants or donor plant treatments such as thermotherapy. Also microbiological quality assurance systems (e.g. Hazard Analysis Critical Control Point; HACCP procedures) have been adapted to the needs of commercial plant tissue culture laboratories. These are aimed at, preventing the introduction of pathogens, into tissue cultures at establishment and in the laboratory. In established in vitro cultures preventative strategies have proved to be essential, since it is extremely difficult to eliminate environmental bacterial and fungal contaminants using, antibiotics and fungicides. In many cases anti-microbial treatments only inhibit contaminants and low levels of contamination persist. In particular, the use of antibiotics against Gram-negative bacteria (including plant pathogenic bacteria and Agrobacterium tumefaciens vector systems used in genetic engineering) has been shown frequently to be extremely difficult or unsuccessful. Detection of latent contamination may involve the use of general and semi-selective microbial growth media or serological and PCR-based molecular techniques for specific pathogens. However, it is often difficult to detect low numbers of latent bacterial contaminants (e.g. levels present following antibiotic treatment or when acidified plant media are used). This poses a particular risk in the production of transgenic plants where the elimination or detection of Agrobacterium tumefaciens-based vector systems cannot be guaranteed with the currently available methodologies. Recent research has also shown that there is a risk of the transmission of human pathogens in plant tissue cultures.     

Environmentally triggered variability in the genetic variance–covariance of herbivory resistance of an exotic plant Solidago altissima

The variability in the genetic variance–covariance (G‐matrix) in plant resistance and its role in the evolution of invasive plants have been long overlooked. We conducted an additional analysis of the data of a reciprocal transplant experiment with tall goldenrod, Solidago altissima, in multiple garden sites within its native range (USA) and introduced range (Japan). We explored the differences in G‐matrix of resistance to two types of foliar herbivores: (a) a lace bug that is native to the USA and recently introduced to Japan, (b) and other herbivorous insects in response to plant origins and environments. A negative genetic covariance was found between plant resistances to lace bugs and other herbivorous insects, in all combinations of garden locations and plant origins except for US plants planted in US gardens. The G‐matrix of the resistance indices did not differ between US and Japanese plants either in US or Japanese gardens, while it differed between US and Japanese gardens in both US and Japanese plants. Our results suggested that the G‐matrix of the plant resistance may have changed in response to novel environmental differences including herbivore communities and/or other biotic and abiotic factors in the introduced range. This may have revealed a hidden trade‐off between resistances, masked by the environmental factors in the origin range. These results suggest that the stability of the genetic covariance during invasion, and the environmentally triggered variability in the G‐matrices of plant resistance may help to protect the plant against multiple herbivore species without changing its genetic architecture and that this may lead to a rapid adaptation of resistance in exotic plants. Local environments of the plant also have a critical effect on plant resistance and should be considered in order to understand trait evolution in exotic plants.     

Plant acquisition of organic nitrogen in boreal forests

Research on plant nitrogen (N) uptake and metabolism has more or less exclusively concerned inorganic N, particularly nitrate. Nevertheless, recent as well as older studies indicate that plants may have access to organic N sources. Laboratory studies have shown that ectomycorrhizal and ericoid mycorrhizal plants can degrade polymeric N and absorb the resulting products. Recent studies have also shown that some non‐mycorrhizal plants are able to absorb amino acids. Moreover, amino acid transporters have been shown to be present in both plant roots and in mycorrhizal hyphae. Although both mycorrhizal and non‐mycorrhizal plants appear to have a capacity for absorbing a range of organic N compounds, is this capacity realized in the field? Several lines of evidence show that plants are outcompeted by microorganisms for organic N sources. Such studies, however, have not addressed the issue of spatial and temporal separation between plants and microorganisms. Moreover, competition studies have not been able to separate uptake by symbiotic and non‐symbiotic microorganisms. Qualitative assessment of organic N uptake by plants has been performed with dual‐labelled glycine in several studies. These studies arrive at different conclusions: some indicate that plants do not absorb this organic N source when competing with other organisms in soil, while others conclude that significant fractions of amino acid N are absorbed as intact amino acid. These variable results may reflect species differences in the ability to absorb glycine as well as differences in experimental conditions and analytical techniques. Although theoretical calculations indicate that organic N might add significant amounts of N to plant N uptake, direct quantitative assessment of the fraction of plant N derived from uptake by organic N sources is a challenge for future research.     

The applicability of the plant vigor and resource regulation hypotheses in explaining Epiblema gall moth–Parthenium weed interactions

A basic question in insect–plant interactions is whether the insects respond to, or regulate plant traits, or a complex mixture of the two. The relative importance of the directions of the influence in insect–plant interactions has therefore been articulated through both the plant vigor hypothesis (PVH) and the resource regulation hypothesis (RRH). This study tested the applicability of these hypotheses in explaining the interactions between Parthenium hysterophorus L. (Asteraceae) and its stem‐galling moth, Epiblema strenuana Walker (Lepidoptera: Tortricidae). Parthenium plants exposed to galling were sampled at three sites in north Queensland, Australia, over a 2‐year period, and the relationship between gall abundance and plant vigor (plant height, biomass, flowers per plant, and branches per plant) was studied. To test the predictions of PVH and RRH, the vigor of parthenium plants protected from galling using insecticides was compared to galled plants and plants that escaped from galling. The vigor of ungalled plants was less than the vigor of galled plants. The higher plant vigor in galled plants was not due to galling, as was evident from insecticide exclusion trials. The insect seemed to preferentially gall the more vigorous plants. These findings support the predictions of the PVH and are contrary to those of RRH. Since gall abundance is linked to plant vigor, galling may have only a limited impact on the vigor of parthenium. This has implications for weed biological control. If the objective of biological control is to regulate the population of a plant by a galling insect, a preference for more vigorous plants by the insect is likely to limit its ability to regulate plant populations. This may explain the paucity of successes against biocontrol of annual weeds using gall insects.     

Limitations of stable carbon isotope analysis for determining natal host origins of tobacco budworm, Heliothis virescens

Differences in the stable carbon isotope ratios of plants utilizing the C3 vs. C4 photosynthetic pathway have been used to broadly identify the natal host origins of herbivorous insects. This study explored whether adequate variation exists between the carbon isotope ratios of different C3 plants in the host range of Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) to enable accurate identification of natal host‐plant species. Isotope ratio mass spectrometry (IRMS) analysis of ¹³C/¹²C ratios of moths reared on four crop plant species [Gossypium hirsutum (L.), Nicotiana tabacum L., Glycine max (L.) Merrill, and Arachis hypogaea L.] and two common weed species [Geranium carolinianum L. and Linaria canadensis (L.) Chaz.] revealed a range of δ¹³C values within that expected for plants utilizing the C3 photosynthetic pathway. Analysis of vegetative and reproductive tissues from the plants utilized in the study resulted in statistically different δ¹³C values for some plant species; nevertheless, the range of δ¹³C values observed for many plant species overlapped. Significant differences in mean δ¹³C values were detected between groups of moths reared on different host‐plant species, but there was no significant correlation between the δ¹³C values of moths vs. the δ¹³C value of plant tissue on which they were reared. Feral tobacco budworm moths collected over 3 years were found to have carbon isotope ratios consistent with those having fed on C3 plants, confirming little utilization of C4 plant species by the insect. Results demonstrate that within the range of C3 host plants tested, carbon isotope signatures are not sufficiently unique to enable a reliable determination of natal origin of feral tobacco budworm with current IRMS technology.     

Small GTPase 'Rop': molecular switch for plant defense responses

The conserved Rho family of GTPases (Rho, Rac, and Cdc42) in fungi and mammals has emerged as a key regulator of diverse cellular activities, such as cytoskeletal rearrangements, programmed cell death, stress-induced signaling, and cell growth and differentiation. In plants, a unique class of Rho-like proteins, most closely related to mammalian Rac, has only been found and termed 'Rop' (Rho-related GTPase from plant [Li et al. (1998) Plant Physiol. 118, 407-417; Yang (2002) Plant Cell 14, S375-S388]). ROPs have been implicated in regulating various plant cellular responses including defense against pathogens. It has been shown that ROPs, like mammalian Rac, trigger hydrogen peroxide production and hence the 'oxidative burst', a crucial component associated with the cell death, most likely via activation of nicotinamide adenine dinucleotide phosphate oxidase in both monocotyledonous and dicotyledonous species. Recent studies have established that ROPs also function as a molecular switch for defense signaling pathway(s) linked with disease resistance. As discerning the defense pathway remains one of the priority research areas in the field of plant biology, this review is therefore particularly focused on recent progresses that have been made towards understanding the plant defense responses mediated by ROPs.