14-3-3蛋白与植物细胞信号转导

14-3-3蛋白通过直接蛋白质-蛋白质相互作用对植物代谢关键酶、质膜H^＋ -ATP酶等发挥广泛调节作用。越来越多证据显示14-3-3蛋白通过与转录因子和其他信号分子结合参与调控植物细胞信号转导。对植物细胞中14-3-3蛋白调控信号转导途径,尤其是植物细胞对胁迫响应的调控机制进行了综述。     

Combined Grazing and Drought Stress Alter the Outcome of Nurse: Beneficiary Interactions in a Semi-arid Ecosystem

Ecosystems - Positive interspecific plant–plant interactions in (semi-)arid ecosystems are crucial for supporting ecosystem diversity and stability, but how interactions respond to grazing...     

Temporal and spatial patterns of 1, 3-β-glucanase and chitinase induction in potato leaves infected by Phytophthora infestans

Infection of potato (Solarium tuberosum L.) leaves with the fungal pathogen Phytophthora infestans caused a similar, strong and coordinated induction of 1, 3-β-glucanases and chitinases in compatible (plant susceptible) and incompatible (plant resistant) interactions of two selected plant cultivars with appropriate races of the fungus. The temporal and spatial patterns of 1, 3-β-glucanase induction were studied in further detail by immunohistochemical and in-situ hybridization methods. Accumulation of the protein was preceded by progressive activation of the corresponding gene, commencing near infection sites and spreading rapidly throughout the whole infected leaf as well as to adjacent, non-infected leaves. Protein and mRNA distribution patterns were nearly identical in compatible and incompatible interactions. In comparison with 1, 3-β-glucanase mRNA, phenyl-alanine ammonia-lyase mRNA accumulated more rapidly and remained restricted to the vicinity of fungal infection sites, in addition to its constitutive occurrence in the vascular bundles. Even more rapid than any detectable mRNA induction was the accumulation of auto fluorescing material in plant cells immediately surrounding fungal structures, particularly and invariably in incompatible interactions and less frequently in compatible interactions. It is concluded that cultivar-race-specific resistance is established early in the interaction of potato leaves with P. infestans and hence the observed massive accumulation of 1, 3-β-glucanase and chitinase is presumably not involved in determining this specificity.     

The Complexity of Factors Driving Volatile Organic Compound Emissions by Plants

The emissions of volatile organic compounds, VOC, from plants have strong relevance for plant physiology, plant ecology, and atmospheric chemistry. We report here on the current knowledge of the many internal (genetic and biochemical) and external (abiotic - temperature, light, water availability, wind, ozone, and biotic - animal, plant and microorganisms interactions) factors that control emission rates of different VOC by altering their synthesis, vapour pressure or diffusion to the atmosphere. The complex net of these factors, their interactions and the different responses of the different VOC produces the large qualitative and quantitative, spatial and temporal variability of emissions and the frequent deviations from current standard emission models. The need for a co-operative multidisciplinary multiscale research to disentangle this complex and important issue of plant VOC emissions is reminded.     

Variation in plant–soil interactions among temperate forest herbs

Plant Ecology - Antagonistic interactions between plants and soil biota promote species diversity in many plant communities but little is known about how these plant–soil interactions...     

14-3-3 proteins fine-tune plant nutrient metabolism

14-3-3 Proteins regulate many cellular processes by binding to phosphorylated proteins. Previous findings suggest a connection between three 14-3-3 isoforms and plant nutrient signaling. To better understand how these 14-3-3s regulate metabolism in response to changes in plant nutrient status, putative new targets involved in nitrogen (N) and sulfur (S) metabolisms have been identified. The interactions between these 14-3-3s and multiple proteins involved in N and S metabolism and altered activity of the target proteins were confirmed in planta. Using a combination of methods, this work elucidates how 14-3-3s function as modulators of plant N and S metabolic pathways.     

Importance,but not intensity of plant interactions relates to species diversity under the interplay of stress and disturbance

The lack of clarity on how the intensity and importance of plant interactions change under the co‐occurrence of stress and disturbance strongly impedes assessing the relative importance of plant interactions for species diversity. We addressed this issue in subalpine grasslands of the French Pyrenees. A natural soil moisture gradient further experimentally stretched at both ends was used and a mowing disturbance treatment was applied at each position along the soil moisture gradient. Changes in intensity and importance of plant interactions were assessed by a neighbour removal experiment using four target ecotypes. A structural equation modelling approach was used to assess the relative impact of stress, disturbance, the intensity and importance of plant interactions on diversity at both the neighbourhood and community scales. Without mowing, changes in intensity and importance of plant interactions only diverged in the dry part of the soil moisture gradient. The intensity of plant interactions linearly shifted from competition to facilitation with increasing stress, while the importance followed a hump‐shaped relationship. Species diversity components were tightly related to the importance of plant interactions only, both the neighbourhood and community scales. Mowing disturbance strongly reduced the importance of facilitation along the soil moisture gradient, and suppressed the relationship between the importance of plant interactions and diversity components. Together, our results highlight that 1) the importance is the best predictor of variations in species diversity in this subalpine herbaceous system, and 2) that fine‐scale processes such as plant interactions can affect the entire plant communities. Finally, our results suggest that high level of constraints due to co‐occurring stress and disturbance can inhibit the effects of plant interactions on species diversity, highlighting their potential role in regulating diversity and the maintenance/extinction of plant communities. Synthesis How plant interactions change along environmental gradients is an unsolved debate, particularly when both stress and disturbance interact. This lack of clarity explains why the relative impact of plant interactions (intensity and importance) on species diversity has been rarely assessed. Using an experimental approach, we found that the importance of plant interactions highly contributed to variation in species diversity, confirming that neighbourhood scale processes such as plant interactions can affect the entire plant communities. The co‐occurrence of stress and disturbance inhibited the effects of plant interactions, highlighting that plant interactions may regulate drops of diversity and the maintenance/extinction of plant communities.     

Associations of like and unlike polysaccharides: Mechanism and specificity in galactomannans,interacting bacterial polysaccharides,and related systems

Chiroptical, rheological, and n.m.r.-relaxation evidence is presented, to identify interactions of two types between different polysaccharides: (1) mutual exclusion of incompatible molecules, with consequent increase in the effective concentration of both; and (2) energetically favourable association of structurally and sterically regular chain-segments. β-1,4-linked plant polysaccharides interact by association of unsubstituted backbone regions, either with like chians, or with sterically compatible, unlike molecules. Extracellular polysaccharides (xanthans) of Xanthomonas plant pathogens maintain their ordered native conformation in solution, and this accounts for their industrially valuable, rheological peculiarities. These materials bind strongly to the plant glycans. Random-coil bacterial gums show no such interactions, although dextran enhances autogelation of galactomannans by exclusion. Extracellular polysaccharides from Arthrobacter species also have ordered native conformations in solution, but do not share the specific interactions of xanthan. Native xanthan shows marked specificity in its interactions with plant glycans, indicating a possible biological role in host-pathogen recognition.     

The effect of arbuscular mycorrhizal fungi Rhizophagus intraradices and soil microbial community on a model plant community in a post-mining soil

Plant Ecology - The aim of this study was to assess the effect of arbuscular mycorrhizal fungi Rhizophagus intraradices and soil microbial groups and their interactions on a simple plant community...     

An efficient three-dimensional rhizosphere modeling capability to study the effect of root system architecture on soil water and reactive transport

Plant and Soil - The objective of this research was to develop a three-dimensional (3D) rhizosphere modeling capability for plant-soil interactions by integrating plant biophysics, water and ion...     

Probing the mechanism of ligand recognition in family 29 carbohydrate-binding modules

The recycling of photosynthetically fixed carbon, by the action of microbial plant cell wall hydrolases, is integral to one of the major geochemical cycles and is of considerable industrial importance. Non-catalytic carbohydrate-binding modules (CBMs) play a key role in this degradative process by targeting hydrolytic enzymes to their cognate substrate within the complex milieu of polysaccharides that comprise the plant cell wall. Family 29 CBMs have, thus far, only been found in an extracellular multienzyme plant cell wall-degrading complex from the anaerobic fungus Piromyces equi, where they exist as a CBM29-1:CBM29-2 tandem. Here we present both the structure of the CBM29-1 partner, at 1.5 A resolution, and examine the importance of hydrophobic stacking interactions as well as direct and solvent-mediated hydrogen bonds in the binding of CBM29-2 to different polysaccharides. CBM29 domains display unusual binding properties, exhibiting specificity for both beta-manno- and beta-gluco-configured ligands such as mannan, cellulose, and glucomannan. Mutagenesis reveals that "stacking" of tryptophan residues in the n and n+2 subsites plays a critical role in ligand binding, whereas the loss of tyrosine-mediated stacking in the n+4 subsite reduces, but does not abrogate, polysaccharide recognition. Direct hydrogen bonds to ligand, such as those provided by Arg-112 and Glu-78, play a pivotal role in the interaction with both mannan and cellulose, whereas removal of water-mediated interactions has comparatively little effect on carbohydrate binding. The interactions of CBM29-2 with the O2 of glucose or mannose contribute little to binding affinity, explaining why this CBM displays dual gluco/manno specificity.     

Latitudinal and climate-driven variation in the strength and nature of biological interactions in New England salt marshes

We examined the linkage between climate and interspecific plant interactions in New England salt marshes. Because harsh edaphic conditions in marshes can be ameliorated by neighboring plants, plant neighbors can have net competitive or facilitative interactions, depending on ambient physical stresses. In particular, high soil salinities, which are largely controlled by solar radiation and the evaporation of marsh porewater, can be ameliorated by plant neighbors under stressful conditions leading to facilitative interactions. Under less stressful edaphic conditions, these same neighbors may be competitors. In this paper, we use this mechanistic understanding of marsh plant interactions to examine the hypothesis that latitudinal and inter-annual variation in climate can influence the nature and strength of marsh plant species interactions. We quantified the relationship between climate and species interactions by transplanting marsh plants into ambient vegetation and unvegetated bare patches at sites north and south of Cape Cod, a major biogeographic barrier on the east coast of North America. We hypothesized that the cooler climate north of Cape Cod would lead to fewer positive interactions among marsh plants. We found both latitudinal and inter-annual variation in the neighbor relations of marsh plants that paralleled latitudinal differences in temperature and salinity. South of Cape Cod, plant neighbor interactions tended to be more facilitative, whereas north of Cape Cod, plant neighbor interactions were more competitive. At all sites, soil salinity increased and plant neighbor interactions were more facilitative in warmer versus cooler years. Our results show that interspecific interactions can be strikingly linked to climate, but also reveal that because the sensitivity of specific species interactions to climatic variation is highly variable, predicting how entire communities will respond to climate change will be difficult, even in relatively simple, well-studied systems.     

Nitrogen deficiency increases volicitin-induced volatile emission,jasmonic acid accumulation,and ethylene sensitivity in maize

Insect herbivore-induced plant volatile emission and the subsequent attraction of natural enemies is facilitated by fatty acid-amino acid conjugate (FAC) elicitors, such as volicitin [N-(17-hydroxylinolenoyl)-L-glutamine], present in caterpillar oral secretions. Insect-induced jasmonic acid (JA) and ethylene (E) are believed to mediate the magnitude of this variable response. In maize (Zea mays) seedlings, we examined the interaction of volicitin, JA, and E on the induction of volatile emission at different levels of nitrogen (N) availability that are known to influence E sensitivity. N availability and volicitin-induced sesquiterpene emission are inversely related as maximal responses were elicited in N-deficient plants. Plants with low N availability demonstrated similar volatile responses to volicitin (1 nmol plant(-1)) and JA (100 nmol plant(-1)). In contrast, plants with medium N availability released much lower amounts of volicitin-induced sesquiterpenes compared with JA, suggesting an alteration in volicitin-induced JA levels. As predicted, low N plants exhibited greater sustained increases in wound- and volicitin-induced JA levels compared with medium N plants. N availability also altered volicitin-E interactions. In low N plants, E synergized volicitin-induced sesquiterpene and indole emission 4- to 12-fold, with significant interactions first detected at 10 nL L(-1) E. Medium N plants demonstrated greatly reduced volicitin-E interactions. Volicitin-induced sesquiterpene emission was increased by E and was decreased by pretreatment the E perception inhibitor 1-methylcyclopropene without alteration in volicitin-induced JA levels. N availability influences plant responses to insect-derived elicitors through changes in E sensitivity and E-independent JA kinetics.     

Plant proteome analysis: a 2004-2006 update

Since the appearance of the review entitled "Plant Proteome Analysis" in Proteomics in February 2004 (Cánovas, F. M., Dumas-Gaudot, E., Recorbert, G., Jorrín, J. et al., Proteomics 2004, 4, 285-298), about 200 original articles focusing on plant proteomics have been published. Although this represents less than 1% of the global proteomics output during this period, it nevertheless reflects an increase in activity over the period 1999-2004. These papers concern the proteome of at least 35 plant species but have concentrated mainly on thale cress (Arabidopsis thaliana) and rice (Oryza sativa). The scientific objectives have ranged from a proteomic analysis of organs, tissues, cell suspensions, or subcellular fractions to the study of plant development and response to various stresses. A number of contributions have covered PTMs and protein interactions. The dominant analytical platform has been 2-DE coupled to MS, but "second generation" techniques such as DIGE, multidimensional protein identification technology, isotope-coded affinity tags, and stable isotope labeling by amino acids in cell culture have begun to make an impact. This review aims to provide an update of the contribution of proteomics to plant biology during the period 2004-2006, and is divided into six sections: introduction, subcellular proteomes, plant development, responses to biotic and abiotic stresses, PTMs, and protein interactions. The conclusions summarize a view of the major pitfalls and challenges of plant proteomics.     

植物病原-媒介昆虫互作:研究进展与展望

大多数植物病毒及一些植物病原细菌由介体昆虫传播。植物病原与介体昆虫关系的研究有助于找到防控介体传播病原的关键环节,因此植物病原与介体昆虫的互作关系是植物病原传播机理研究中的核心问题。本文概述了国内外在植物病原与介体昆虫互作研究的最新进展,推介了本专辑论文的主要内容,并在此基础上,从生态和进化的角度提出了在植物病原-媒介昆虫互作研究中以下3个值得关注的研究方向:(1)植物病原与介体昆虫互作对生态系统的影响;(2)昆虫介体传播植物病毒的不同方式之间的关联性以及病毒、介体和植物之间的协同进化关系;(3)自然条件下植物病原-媒介昆虫互作的机理。植物病原与媒介昆虫互作的研究,既是生态和进化的理论问题,也和植物病原及其介体昆虫的绿色防控密切相关。     

Plant scent and plant–insect interactions—Review and outlook from a macroevolutionary perspective

The astonishing diversity of plants and insects and their entangled interactions are cornerstones in terrestrial ecosystems. Co-occurring with species diversity is the diversity of plant secondary metabolites (PSMs). So far, their estimated number is more than 200 000 compounds, which are not directly involved in plant growth and development but play important roles in helping plants handle their environment including the mediation of plant–insect interactions. Here, we use plant volatile organic compounds (VOCs), a key olfactory communication channel that mediates plant–insect interactions, as a showcase of PSMs. In spite of the cumulative knowledge of the functional, ecological, and microevolutionary roles of VOCs, we still lack a macroevolutionary understanding of how they evolved with plant–insect interactions and contributed to species diversity throughout the long coevolutionary history of plants and insects. We first review the literature to summarize the current state-of-the-art research on this topic. We then present various relevant types of phylogenetic methods suitable to answer macroevolutionary questions on plant VOCs and suggest future directions for employing phylogenetic approaches in studying plant VOCs and plant–insect interactions. Overall, we found that current studies in this field are still very limited in their macroevolutionary perspective. Nevertheless, with the fast-growing development of metabolome analysis techniques and phylogenetic methods, it is becoming increasingly feasible to integrate the advances of these two areas. We highlight promising approaches to generate new testable hypotheses and gain a mechanistic understanding of the macroevolutionary roles of chemical communication in plant–insect interactions.     

植物激素信号之间的相互作用

植物激素问的相互作用对植物的正常发育来说非常重要。不同植物激素之间存在相互协同、对抗和因果等关系,以精细调控植物的发育和对环境的反应等,植物激素信号之间的相互作用已成为植物细胞中不同信号间相互作用机制研究的模式系统。现对不同植物激素在生物合成、代谢、运输和信号转导途径等层次上的相互作用进行综述,并对这一领域的研究进行了总结和展望。     

Maize 9-lipoxygenase ZmLOX3 controls development, root-specific expression of defense genes, and resistance to root-knot nematodes

Root-knot nematodes (RKN) are severe pests of maize. Although lipoxygenase (LOX) pathways and their oxylipin products have been implicated in plant-nematode interactions, prior to this report there was no conclusive genetic evidence for the function of any plant LOX gene in such interactions. We showed that expression of a maize 9-LOX gene, ZmLOX3, increased steadily and peaked at 7 days after inoculation with Meloidogyne incognita RKN. Mu-insertional lox3-4 mutants displayed increased attractiveness to RKN and an increased number of juveniles and eggs. A set of jasmonic acid (JA)- and ethylene (ET)-responsive and biosynthetic genes as well as salicylic acid (SA)-dependent genes were overexpressed specifically in the roots of lox3-4 mutants. Consistent with this, levels of JA, SA, and ET were elevated in lox3-4 mutant roots, but not in leaves. Unlike wild types, in lox3-4 mutant roots, a phenylalanine ammonia lyase (PAL) gene was not RKN-inducible, suggesting a role for PAL-mediated metabolism in nematode resistance. In addition to these alterations in the defense status of roots, lox3-4 knockout mutants displayed precocious senescence and reduced root length and plant height compared with the wild type, suggesting that ZmLOX3 is required for normal plant development. Taken together, our data indicate that the ZmLOX3-mediated pathway may act as a root-specific suppressor of all three major defense signaling pathways to channel plant energy into growth processes, but is required for normal levels of resistance against nematodes.     

Multiple spatial scales affect direct and indirect interactions between a non-native and a native species

Plant Ecology - Plant–plant interactions influence community assembly and species responses to environmental change. However, species interactions are complex phenomena influenced by context...