野生稻有利基因的发掘和利用

摘要: 野生稻作为栽培稻的野生亲缘种, 具有许多优良的性状和有利基因, 是栽培稻品种进一步改良的天然遗传种质资源库。其中, 野生稻对病虫害的抗性、对各种逆境的耐受性以及胞质雄性不育等, 已广泛应用于现代栽培稻的育种改良。文章综述了野生稻种质资源的有利性状及相应控制基因的发掘, 探讨了其在今后水稻育种中的应用潜力。     

栽培植物野生近缘种的保护与利用

栽培植物是人类赖以生存和发展的重要物质基础。全球人口与人均需求量的持续增长导致对植物资源的需求与日俱增。栽培植物较低的遗传多样性是限制其产量增长和质量提高的主要因素。栽培植物野生近缘种在自然环境中积累了丰富的遗传变异, 并在应对环境变化的过程中产生了很多新的适应性状, 是栽培植物种质创新和品种改良的重要遗传资源。然而, 栽培植物野生近缘种的存续和自然进化因生境破坏以及全球气候变化等正面临严重威胁, 需要采取有效的措施进行保护。本文总结了国内外对栽培植物野生近缘种进行原生境保护与迁地保护所取得的进展, 并基于我国实际情况提出了栽培植物野生近缘种的保护建议。此外, 本文还对栽培植物野生近缘种利用技术进行了梳理, 探讨了栽培植物野生近缘种遗传资源可持续利用的新思路。最后, 我们以长江流域几种代表性栽培植物为例, 对主要作物类型的保护与利用情况进行了讨论。     

作物野生近缘种的保护与利用

作物野生近缘种将是保证下一世纪粮食充足的重要因素。近30余年来国际国内非常重视作物野生种质资源的搜集、保存、鉴定、评价和利用的研究。我国作物野生近缘种特别丰富,同时受威胁非常严重。因此,加大力度开展作物及其野生近缘种种质资源的遗传多样性、保存技术、种质创新和利用的研究是刻不容缓的。     

茶条槭自然种群种子和果实表型多样性研究

为探析茶条槭(Acer ginnala)种子和果实表型差异程度及变异规律,该研究采用巢式方差分析、主成分分析、聚类分析等方法,对茶条槭主要分布区内7个种群种子和果实的12个表型性状进行比较研究,分析茶条槭种群间和种群内的表型多样性以及与地理生态因子的关系。结果表明:除种子长/宽(SLW)外,其它11个表型性状在茶条槭种群间和种群内均具有显著差异;各性状平均变异系数(CV)为13.90%,变异幅度为8.14%～32.08%;种群间翅果性状的平均变异系数(15.63%)高于种子性状的平均变异系数(8.71%),表明种子性状的稳定性高于果实性状。主成份分析中,果实形态特征对茶条槭种群表型的贡献率大于种子贡献率。种群间表型分化系数为35.47%,说明种群内变异(64.53%)大于种群间变异(35.47%),暗示变异主要来源于种群内变异。茶条槭种子和果实表型性状受地理生态因子影响较小,主要受自身遗传因素的影响。基于种群间欧式距离的聚类分析将茶条槭7个种群分为2大支,没有严格按照地理距离而聚类,表明茶条槭种群表型性状变异的不连续性。茶条槭不同种群种子和果实具有较高的表型多样性,与其分布范围和生物学特性有关。     

Ethnobotany of the genusCyphomandra (Solanaceae)

Plants of the genusCyphomandra (Solanaceae) have long been utilized for their edible fruits in their native Latin America. The best-known species is the domesticated tree tomato or tamarillo,Cyphomandra betacea. This species, popular as a raw or cooked fruit, is widely cultivated in Andean South America and is now dispersed worldwide in subtropical areas. Its origin and wild relatives are still unknown, but there are tentative reports of wild populations ofC. betacea in southern Bolivia and northwestern Argentina. Wild species ofCyphomandra such asC. hartwegii, C. sibundoyensis, andC. cajanumensis also produce edible fruits. Other species ofCyphomandra are used in medicinal preparations and as dyes. This group of plants is of increasing economic importance and may have considerable potential for future exploitation.     

Nutritional and Morphological Traits of Invasive and Exotic Fleshy‐fruits in South Africa

While fleshy‐fruited invasive alien plants are recognized as some of the worst invaders on a global scale, until recently, little consideration has been given to the frugivores that feed on these fruits and, more specifically, the fruit traits, which may influence this. We investigated a series of morphological and nutritive fruit traits for ca 30 species of fleshy‐fruited invasive alien and exotic species in South Africa. Invasive alien fruit traits were compared with comparable traits of a similar sample size of indigenous fleshy fruits, which occur in the same area. Finally, the similarity of traits for the same invasive alien species was compared with those fruits in Australia. Invasive alien fleshy fruits were similar in morphology, but greater in some nutritive aspects when compared with indigenous fruits. Furthermore, they were very similar in all aspects to their counterparts in Australia. Most seeds of invasive fleshy fruits were small and light, which may explain some of their invasive success, as benefits associated with small seededness may promote invasive potential. Nutritionally, most invasive alien fleshy‐fruits were hexose‐dominant, containing low lipid and nitrogen content. While frugivore preference trends remain to be formally investigated, this study provides insights into fruit traits, which may tentatively outline why invasive fruits are universally fed on and thus successfully spread.     

CWRML: representing crop wild relative conservation and use data in XML

Background  

Crop wild relatives are wild species that are closely related to crops. They are valuable as potential gene donors for crop improvement and may help to ensure food security for the future. However, they are becoming increasingly threatened in the wild and are inadequately conserved, both in situ and ex situ. Information about the conservation status and utilisation potential of crop wild relatives is diverse and dispersed, and no single agreed standard exists for representing such information; yet, this information is vital to ensure these species are effectively conserved and utilised. The European Community-funded project, European Crop Wild Relative Diversity Assessment and Conservation Forum, determined the minimum information requirements for the conservation and utilisation of crop wild relatives and created the Crop Wild Relative Information System, incorporating an eXtensible Markup Language (XML) schema to aid data sharing and exchange.     

The role of domestication and maternal effects on seed traits of crop–wild sunflower hybrids (Helianthus annuus)

Hybridisation between crops and their wild relatives may promote the evolution of weeds. Seed germination and dormancy are the earliest life‐history traits and are highly influenced by the maternal parent. However, the ecological role of the maternal effect on seed traits in the evolution of crop–wild hybrids has received little attention. In this study, we test the relative importance of maternal and hybridisation effects on seed traits of the first generation of crop–wild sunflower hybrids (Helianthus annuus). Seed germination was tested in two wild populations with contrasting dormancy, two cultivated materials and their reciprocal crosses at four different times after harvest and three different temperatures. Seed germination at each of the four times, after ripening response and secondary dormancy were recorded along with four morphological traits. Additionally, the pericarp anatomy was analysed with light and scanning electron microscopy. We observed strong maternal effects on all seed traits. Seed germination, morphology and pericarp anatomy differed largely between the crop and wild seeds and these traits in the crop–wild hybrids resembled their female parent. Slight but significant hybridisation effects were observed in germination, mainly in seeds produced on wild plants. Crop hybridisation changed seed germination, the after ripening response and secondary dormancy in the crop direction. Morphological and anatomical traits associated with domestication strongly correlated with the observed differences in seed germination and dormancy in crop–wild sunflower hybrids. The large maternal effects along with the evolutionary divergence in seed traits were responsible for the large phenotypic differences observed in crop–wild hybrids with the same genetic composition. Wild‐like seed traits of hybrids suggest that there are no barriers to crop gene introgression at the seed level whereas crop‐like seed traits could be strongly selected against, conditioning the selection of traits expressed later in the life cycle and in the next generations.     

Fruit selection by Andean forest birds: influence of fruit functional traits and their temporal variation

Fruit selection, i.e., the consumption of fruits disproportionately to their availability, results from the interaction between diet preferences and ecological factors that modify them. We assessed the importance of functional fruit traits to explain fruit selection by birds in Andean subtropical forests, taking into account temporal variation in trait distribution in the assembly of available fruits. During 2 yr, we measured the abundance of ripe fruits and their consumption by birds in a 6‐ha plot during 11 bimonthly samplings, and we used 17 phenological, morphological, and nutritional traits to characterize fruits selected by four bird species. Fruit selection was pervasive year‐round, highly variable over time and across bird species. Fruit species were selected over time periods shorter than their ripening phenology, and the selection of fruits with particular traits was specific to the fruit‐eating species. Maximization in pulp reward per consumed fruit seems to be the main driving force behind fruit selection, indicating that birds select fruits with traits that directly affect net energy gain. Our results can be interpreted in a framework of a hierarchy of foraging decisions, under which the spatiotemporal context of the fruiting environment modifies the relative intake rates of a particular fruit, while the ability to discriminate fruit contents becomes increasingly important on a smaller dimension. We show that fruit‐selection properties are contingent on specific fruit traits and particular spatiotemporal conditions, which modify the structure of mutualistic interactions.     

Geographic variation in fruit colour is associated with contrasting seed disperser assemblages in a south‐Andean mistletoe

Fruit colour influences fruit choice by seed dispersers. The mistletoe Tristerix corymbosus (Loranthaceae) produces mature fruits of two different colours in two different biomes: yellow in the Chilean matorral and green in the temperate forest of southern South America. We conducted field surveys to establish the association between fruit colour and disperser identity throughout the entire geographical range of T. corymbosus. We selected 22 populations, eight of which were located in the Chilean matorral and 14 in the temperate forest south of the matorral. To identify the seed dispersers of the mistletoe we used direct observation, camera traps, and live‐trapping of small mammals. We also report experiments to assess fruit selection by seed dispersers based on differences in colour. The assemblages of dispersers of T. corymbosus differ between the two biomes: yellow fruits in Chilean matorral are exclusively dispersed by three bird species while green fruits in the temperate forest are exclusively dispersed by a marsupial. The differences in the assemblages of seed dispersers can be explained by differences in food‐finding strategies between the two assemblages. Green fruits in temperate forest are not easily detected by birds, while colour might not be an important cue for the marsupial because it is nocturnal and uses other senses to locate food. We propose that the association between the marsupial and the green‐fruited mistletoe constitutes an ecological fitting rather than the outcome of a co‐evolutionary process. The marsupial might have allowed the mistletoe T. corymbosus to retain green coloration in mature fruit, a condition to which it is preadapted by a slower ripening process in temperate forest populations.     

Influence of plant domestication on plant-pollinator interactions: Floral attributes and floral visitor communities in wild and cultivated squash plants

Premise

Domestication of plant species results in phenotypic modifications and changes in biotic interactions. Most studies have compared antagonistic plant-herbivore interactions of domesticated plants and their wild relatives, but little attention has been given to how domestication influences plant-pollinator interactions. Floral attributes and interactions of floral visitors were compared between sister taxa of the genus Cucurbita (Cucurbitaceae), the domesticated C. moschata, C. argyrosperma ssp. argyrosperma and its wild progenitor C. argyrosperma ssp. sororia in the place of origin.

Methods

We conducted univariate and multivariate analyses to compare floral morphological traits and analyzed floral reward (nectar and pollen) quantity and quality between flowers of wild and domesticated Cucurbita taxa. Staminate and pistillate flowers of all three taxa were video recorded, and visitation and behavior of floral visitors were registered and analyzed.

Results

Most floral morphological characteristics of flowers of domesticated taxa were larger in both staminate and pistillate flowers. Staminate and pistillate flowers presented distinct correlations between floral traits and integration indices between domesticated and wild species. Additionally, pollen quantity and protein to lipid ratio were greater in domesticated species. Cucurbit pollen specialists, Eucera spp., had the highest probability of visit for all Cucurbita taxa.

Conclusions

We provide evidence that floral traits of domesticated and wild Cucurbita species experienced different selection pressures. Domesticated Cucurbita species may have more resources invested towards floral traits, thereby increasing attractiveness to pollinators and potentially plant reproductive success. Wild ancestor plant populations should be conserved in their centers of origin to preserve plant-pollinator interactions.     

DIFFERENT PHYSIOLOGICAL RESPONSES OF FOUR MARINE SYNECHOCOCCUS STRAINS (CYANOPHYCEAE) TO NICKEL STARVATION UNDER IRON‐REPLETE AND IRON‐DEPLETE CONDITIONS1

Synechococcus species are important primary producers in coastal and open‐ocean ecosystems. When nitrate was provided as the sole nitrogen source, nickel starvation inhibited the growth of strains WH8102 and WH7803, while it had little effect on two euryhaline strains, WH5701 and PCC 7002. Nickel was required for the acclimation of Synechococcus WH7803 to low iron and high light. In WH8102 and WH7803, nickel starvation decreased the linear electron transport activity, slowed down Q_A reoxidation, but increased the connectivity factor between individual photosynthetic units. Under such conditions, the reduction of their intersystem electron transport chains was expected to increase, and their cyclic electron transport around PSI would be favored. Nickel starvation decreased the total superoxide dismutase (SOD) activity of WH8102 and WH7803 by 30% and 15% of the control, respectively. The protein‐bound ⁶³Ni of the oceanic strain WH8102 comigrated with SOD activity on nondenaturing gels and thus provided additional evidence for the existence of active NiSOD in Synechococcus WH8102. In WH7803, it seems likely that nickel starvation affected other metabolic pathways and thus indirectly affected the total SOD activity.     

Foraging Behaviour of the Brown Hyaena (Hyaena brunnea Thunberg, 1820) in the Southern Kalahari

Observations on six free ranging adult brown hyaenas (Hyaena brunnea) fitted with radio collars and beta lights were supplemented by observations on three untagged large cubs and by tracking spoor. Brown hyaenas are predominantly nocturnal and cover large distances alone each night searching for vertebrate remains and other food. Carrion is mainly located by olfactory sense, although auditory cues are also used. Excess food is often stored for short periods. Wild fruits and birds' eggs are eaten and hunting behaviour is directed towards small vertebrates and insects. Some adaptations of the brown hyaena to its environment are discussed.     

Fruit Mineral Contents of Six Wild Species of the North Andean Patagonia, Argentina

The fruit mineral contents (K, Ca, Ba, Br, Zn, Co, Cr, Fe, Na, Rb, Cs, and Sr) of four native and two exotic naturalized shrubs growing in different areas of the Andean Patagonian region of Argentina were investigated. Native species Berberis darwinii, Berberis microphylla (Berberidaceae), Aristotelia chilensis (Elaeocarpaceae) and Ribes magellanicum (Saxifragaceae) produce small berries while the fruits of the exotic species Rosa rubiginosa and Rosa canina (Rosaceae) are aggregates of aquenes. They are used to prepare jams, tea, liquors, and ice creams. Native shrub fruits had higher content of Br, Zn, Co, Cr, Fe, Mo, and Na than those of the exotic naturalized species. Rosa species showed the highest contents of Ca and Ba in their fruits (the mean content doubled those of the native plant fruits). The fruit nutrient content found in the studied species was similar or higher than other values reported for fruits of temperate and tropical species in the world.     

Effects of life-history traits and species distribution on genetic structure at maternally inherited markers in European trees and shrubs

Aim To examine relationships between life‐history traits, ecological and chorological characteristics of woody plant species and patterns of genetic differentiation among populations as assessed by chloroplast DNA (cpDNA) markers, and to compare them with patterns previously described from nuclear markers. Location Europe. Methods Data on cpDNA variation were compiled for 29 temperate European broad‐leaved tree and shrub species. Six qualitative and three quantitative characters of the species were tested for their relationship with two parameters of genetic population differentiation (G_ST and N_ST). Both direct species comparisons and phylogenetically independent contrast analyses were performed. Results When the phylogeny was not taken into account, five characters were significantly related to levels of population differentiation. The relationship disappeared in all but two cases (distribution type and seed mass) when analyses controlled for phylogenetic relationships among species. Main conclusions The correlation between distribution type (boreal‐temperate or temperate) and cpDNA differentiation of temperate European woody plant species suggests that their Quaternary history, in particular the location and isolation of their glacial refugia, is an important determinant of their present‐day level of genetic structure. By contrast, the relationship between life‐history traits and genetic differentiation at maternally inherited markers is weaker, especially when phylogenetic effects are controlled for.     

Modified dispersal‐related traits in disjunct populations of bird‐dispersed Frangula alnus (Rhamnaceae): a result of its Quaternary distribution shifts?

Many European tree species survived Pleistocene glaciations in Mediterranean refugia and rapidly recolonized temperate Europe afterwards. Inter‐ and postglacial migration processes are assumed to have catalized evolutionary optimizations of dispersal‐related traits, but up to now empirical evidence is lacking in vertebrate‐dispersed plants. We investigated if south Iberian glacial relict and central European “colonizer” populations of the bird‐dispersed tree Frangula alnus have experienced differentiations of dispersal‐related traits which increase the mobility of northern populations. A comparison of lifetime reproductive strategy, disperser guilds, ripening phenology, and fruit design revealed considerable differences. Compared to south Iberian conspecifics, central European plants were considerably smaller and experienced a highly accelerated generation turnover. In south Iberian populations seed dispersal was carried out almost completely by resident birds which occurred in constant abundances throughout the ripening season. In contrast, central European seeds were dispersed by migrants whose abundances changed considerably during the ripening season. Several bird species were involved in both study areas but rendered different importance for seed dispersal. The fruit ripening pattern was highly asynchronous throughout the ripening season in south Iberia, while central European trees showed a complex ripening sequence which resulted in a significant correlation between fruit abundance and changing disperser availability. Central European fruits were smaller and showed a considerably smaller seed load than south Iberian fruits, thus presumably being more attractive for their small‐sized main dispersers (Sylvia warblers). Chemical analyses revealed significant differences in contents of water, glucose, fructose, proteins, ash. and phenolic compounds. The extensive differentiation of dispersal‐related traits in F. alnus suggests that even weak selective pressures by frugivores may induce evolutionary adjustments of dispersal traits over large time scales. We suggest that the differences we observe today evolved during the species' distribution shifts in the Quaternary.     

Gene Flow and its Consequences in Sorghum spp.

Gene flow between crops and their weedy or wild relatives can be problematic in modern agricultural systems, especially if it endows novel adaptive genes that confer tolerance to abiotic and biotic stresses. Alternatively, gene flow from weedy relatives to domesticated crops may facilitate ferality through introgression of weedy characteristics in the progeny. Cultivated sorghum (Sorghum bicolor), is particularly vulnerable to the risks associated with gene flow to several weedy relatives, johnsongrass (S. halepense), shattercane (S. bicolor ssp. drummondii) and columbusgrass (S. almum). Johnsongrass and shattercane are common weeds in many sorghum production areas around the world. Sorghum varieties with adaptive traits developed through conventional breeding or novel transgenesis pose agronomic and ecological risks if transferred into weedy/wild relatives. Knowledge of the nature and characteristics of gene flow among different sorghum species is scarce, and existing knowledge is scattered. Here, we review current knowledge of gene flow between cultivated sorghum and its weedy and wild relatives. We further discuss potential avenues for addressing gene flow through genetic, molecular, and field level containment, mitigation and management strategies to facilitate successful deployment of novel traits in this economically important crop species.     

Practical applications of in vitro propagation: Present situation and future prospects

Abstract

This article surveys the techniques and approaches used in the in vitro propagation of economically important plants. The current state of the art for each major class of plants, namely ornamentals, vegetable and agronomic crops, temperate fruits and forest trees is described. The advantages of vegetative propagation in general and the specific advantages which micropropagation offers in the domestication, breeding and conservation of plants are listed. Specific problems associated with in vitro propagation such as juvenility vs maturation, vitrification, rooting and morphological or physiological variations are discussed.     

Comparative membrane proteomics reveal contrasting adaptation strategies for coastal and oceanic marine Synechococcus cyanobacteria

Marine cyanobacteria genus Synechococcus are among the most abundant and widespread primary producers in the open ocean. Synechococcus strains belonging to different clades have adapted distinct strategies for growth and survival across a range of marine conditions. Clades I and IV are prevalent in colder, mesotrophic, coastal waters, while clades II and III prefer warm, oligotrophic open oceans. To gain insight into the cellular resources these unicellular organisms invest in adaptation strategies we performed shotgun membrane proteomics of four Synechococcus spp. strains namely CC9311 (clade I), CC9605 (clade II), WH8102 (clade III) and CC9902 (clade IV). Comparative membrane proteomes analysis demonstrated that CC9902 and WH8102 showed high resource allocation for phosphate uptake, accounting for 44% and 38% of overall transporter protein expression of the species. WH8102 showed high expression of the iron uptake ATP-binding cassette binding protein FutA, suggesting that a high binding affinity for iron is possibly a key adaptation strategy for some strains in oligotrophic ocean environments. One protein annotated as a phosphatase 2c (Sync_2505 and Syncc9902_0387) was highly expressed in the coastal mesotrophic strains CC9311 and CC9902, constituting 14%–16% of total membrane protein, indicating a vital, but undefined function, for strains living in temperate mesotrophic environments.