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PubMed2026

Multi-season analysis reveals hundreds of drought-responsive genes in sorghum.

Persistent drought affects global crop production and is becoming more severe in many parts of the world in recent decades. Deciphering how plants respond to drought will facilitate the development of flexible mitigation strategies. Sorghum bicolor L. Moench (sorghum), a major cereal crop and an emerging bioenergy crop, exhibits remarkable resilience to drought. To better understand the molecular traits that underlie sorghum's remarkable drought tolerance, we undertook a large-scale sorghum gene expression profiling effort, totaling nearly 1500 transcriptome profiles, across a 3-year field study with replicated plots in California's Central Valley. This study included time-resolved gene expression data from roots and leaves of two sorghum genotypes, BTx642 and RTx430, with different pre-flowering and post-flowering drought-tolerance adaptations under control and drought conditions. Quantification of genotype-specific drought tolerance effects was enabled by de novo sequencing, assembly, and annotation of both BTx642 and RTx430 genomes. These reference-quality genomes were used to construct a pangene set for characterizing conserved and genotype-specific expression. By integrating time-resolved transcriptomic responses to drought in the field across three consecutive years, we identified a set of 726 drought-responsive genes that responded similarly in all 3 years of our field study. Functional enrichment analysis identified abiotic stress, secondary cell wall-related processes and metabolism as particularly affected under both types of drought stress. We also found that some glyoxylate cycle pathway genes, including malate synthase and isocitrate lyase, are differentially regulated particularly during post-flowering drought stress, implicating this pathway as potentially important for drought responsiveness. This expansive dataset represents a unique resource for sorghum and drought research communities and provides a methodological framework for the integration of multi-faceted time-resolved transcriptomic datasets.

Sorghum↗
PubMed2002

Belowground herbivory by insects: influence on plants and aboveground herbivores.

Investigations of plant-herbivore interactions continue to be popular; however, a bias neglecting root feeders may limit our ability to understand how herbivores shape plant life histories. Root feeders can cause dramatic plant population declines, often associated with secondary stress factors such as drought or grazing. These severe impacts resulted in substantial interest in root feeders as agricultural pests and increasingly as biological weed control agents, particularly in North America. Despite logistical difficulties, establishment rates in biocontrol programs are equal or exceed those of aboveground herbivores (67.2% for aboveground herbivores, 77.5% for belowground herbivores) and root feeders are more likely to contribute to control (53.7% versus 33.6%). Models predicting root feeders would be negatively affected by competitively superior aboveground herbivores may be limited to early successional habitats or generalist root feeders attacking annual plants. In later successional habitats, root feeders become more abundant and appear to be the more potent force in driving plant performance and plant community composition. Aboveground herbivores, even at high population levels, were unable to prevent buildup of root herbivore populations and the resulting population collapse of their host plants. Significant information gaps exist about the impact of root feeders on plant physiology and secondary chemistry and their importance in natural areas, particularly in the tropics.

Animals↗
PubMed1983

Advancing in tandem: clinical endocrinology and clinical chemistry.

Here I review some of the recent accomplishments in clinical endocrinology and clinical chemistry, point out the direction of future work, and try to predict some of the advances of the next decade. Endocrinology, perhaps more than any other branch of clinical medicine, is rooted in biochemistry and physiology. Endocrinologists have been leaders in the development of methods, which have been adapted by clinical chemists for wider applications than those conceived originally. For the sake of brevity, I shall not recount the early history of endocrinology in this century--or the enormous progress since Starling coined the term "hormone" and stated the physiological role of these chemical messengers in 1905. Progress in endocrinology in recent years has been astounding.

Calcium↗
PubMed1993

[Aortic valvuloplasty in acquired valvular disease].

On the basis of the results of studying the morphology, biomechanics, and physiology of the aortic root and the cusps of the aortic valve the authors suggest a substantiated set of surgical manipulations which allow the patient's natural valve to be preserved. Coarse calcinosis of the cusps and fibrous ring of the aortic root is the only absolute contraindication for valvuloplasty. The authors' clinical experience consists of the first 100 operations. Hospital mortality--8.0%. With intraoperative appraisal of hemodynamics, good correction of the abnormality was achieved practically in all patients. The maximal follow-up period by April, 1991 was 5.5 years. During that period four patients were again subjected to operation because aortic insufficiency recurred. The authors recommend their experience with plastic operations on the aortic valve for wide clinical application.

Adolescent↗
PubMed1998

Mortal: A mutant of white clover defective in nodal root development

A monogenic dominant mutant of white clover (Trifolium repens L.), designated Mortal, which is defective in the formation of adventitious nodal roots, is described. Mortal plants grown at temperatures ranging from 10 to 25 degreesC do not initiate nodal root primordium development. However, all other aspects of plant development are normal, including the formation of lateral roots and wound-induced adventitious roots. In some genetic backgrounds, the Mortal mutation has a temperature-sensitive conditional phenotype. Mortal plants shifted from growing conditions of 20 to 30 degreesC for 2 to 3 d form nodal root meristems. However, new nodes that develop after plants are returned to 20 degreesC exhibit the mutant phenotype. The capacity to form nodal roots on cuttings placed in water is also influenced by the genetic background of the Mortal mutation. Genetic analysis established that the physiological reversion of Mortal to nodal root formation is controlled by at least two separate dominant genetic loci, one for Nodal water response (Now) and one for Nodal temperature response (Not); the Now locus has a dominant epistatic interaction with the Not locus. The conditional nature of Mortal should provide opportunities for the identification of genetic and physiological mechanisms that influence the development of nodal roots.

Journal Article↗
PubMed1990

Physiological Characterization of a Single-Gene Mutant of Pisum sativum Exhibiting Excess Iron Accumulation: I. Root Iron Reduction and Iron Uptake.

Root systems of mutant (E107) and parental (cv ;Sparkle') Pisum sativum genotypes were studied to determine the basis for excess Fe accumulation in E107. Plants were grown with (+Fe-treated) or without (-Fe-treated) added Fe(III)-N,N'-ethylenebis[2-(2-hydroxyphenyl)glycine] in aerated nutrient solutions. Daily measurements of Fe(III) reduction indicated a four-to seven-fold higher reduction rate in +Fe- or -Fe-treated E107, and -Fe-treated Sparkle, when compared with +Fe-treated Sparkle. An agarose-based staining technique used to localize Fe(III) reduction, revealed Fe(III) reduction over most of the length of the roots (but not at the root apices) in both E107 treatments and -Fe-treated Sparkle. In +Fe-treated Sparkle, Fe(III) reduction was either nonexistent or localized to central regions of the roots. Measurements of short-term Fe influx (with 0.1 millimolar (59)Fe(III)-ethylenediaminetetraacetic acid) was also enhanced (threefold) in +Fe- or -Fe-treated E107 and -Fe-treated Sparkle, relative to +Fe-treated Sparkle. The physiological characteristics of E107 root systems, which are similar to those seen in Fe-deficient Sparkle, have led us to conclude that the mutation causes E107 to act functionally as an Fe-deficient plant, and appears to explain the excess Fe accumulation in E107.

Journal Article↗
PubMed2003

Root factors induce mitochondrial-related gene expression and fungal respiration during the developmental switch from asymbiosis to presymbiosis in the arbuscular mycorrhizal fungus Gigaspora rosea.

During spore germination, arbuscular mycorrhizal (AM) fungi show limited hyphal development in the absence of a host plant (asymbiotic). In the presence of root exudates, they switch to a new developmental stage (presymbiotic) characterized by extensive hyphal branching. Presymbiotic branching of the AM fungus Gigaspora rosea was induced in liquid medium by a semipurified exudate fraction from carrot (Daucus carota) root organ cultures. Changes in RNA accumulation patterns were monitored by differential display analysis. Differentially appearing cDNA fragments were cloned and further analyzed. Five cDNA fragments could be identified that show induced RNA accumulation 1 h after the addition of root exudate. Sequence similarities of two fragments to mammalian Nco4 and mitochondrial rRNA genes suggested that root exudates could influence fungal respiratory activity. To support this hypothesis, additional putative mitochondrial related-genes were shown to be induced by root exudates. These genes were identified after subtractive hybridization and putatively encode a pyruvate carboxylase and a mitochondrial ADP/ATP translocase. The gene GrosPyc1 for the pyruvate carboxylase was studied in more detail by cloning a cDNA and by quantifying its RNA accumulation. The hypothesis that respiratory activity of AM fungi is stimulated by root exudates was confirmed by physiological and cytological analyses in G. rosea and Glomus intraradices. Oxygen consumption and reducing activity of both fungi was induced after 3 and 2 h of exposition with the root factor, respectively, and the first respiration activation was detected in G. intraradices after approximately 90 min. In addition, changes in mitochondrial morphology, orientation, and overall biomass were detected in G. rosea after 4 h. In summary, the root-exuded factor rapidly induces the expression of certain fungal genes and, in turn, fungal respiratory activity before intense branching. This defines the developmental switch from asymbiosis to presymbiosis, first by gene activation (0.5-1 h), subsequently on the physiological level (1.5-3 h), and finally as a morphological response (after 5 h).

Cell Respiration↗
PubMed2006

[Contents comparison of resveratrol and polydatin in the wild Polygonum cuspidatum plant and its tissue cultures].

OBJECTIVE: To compare the contents of resveratrol and polydatin in some materials of Polygonum cuspidatum from various sources, so to screen and obtain the suitable cultures for the following metabolism regulation study. METHOD: RP-HPLC method was applied to simultaneously assay resveratrol and polydatin in different samples. RESULT: By the modified methods of extraction and determination, large amount of materials were screened. The results indicated that the contents of resveratrol and polydatin in root and rhizome were evidently higher than those in the leave and stems. The content of polydatin in the seedlings cultured indoor for three months was 1.27% and showed a 1.25-time increse than that in the wild plants, while the content of resveratrol (0.401%) approached that in the wild plants. Both of resveratrol and polydatin could be examined from different tissue cultures of P. cuspidatum, such as the sterile seedlings, callus, suspended cells and hairy roots, and the levels of them were closely related to the growth speed, physiological status and developmental phase. Hairy roots had the highest potentiality in several tested cultures and the increase rate of dry weight was 8.29 when cultured in vitro for 30 days, and showed a 8.4-fold and a 192.8-fold increase compared with those of natural roots and suspended cells, respectively. The content of polydatin in the hairy roots was up to 0.037% and that of resveratrol was 0.007%. CONCLUSION: The established analysis method is rapid, simple and accurate, especially adapted to the simultaneous determination of resveratrol and polydatin in massive biological samples. Hairy-root cultures have the superiority among the tested materials of P. cuspidatum and are suitable for the large-scale biomass and consistent production of efficient constituents.

Biomass↗
PubMed1977

[Animal model for the etiopathogenesis of sialadenitis].

A longitudinal study with patient-specific jaw models and simultaneous X-Rays was undertaken to examine the eruption behaviour of the mandibular premolars following physiological and pathological resorption of the roots of primary teeth. 1. The molars of the first dentition fall out earlier after pathological resorption of the roots of primary teeth. In the presence of an occlusal bony bridge the appearance of a new tooth may take years. The eruption of the replacing tooth is delayed or it may be retained. 2. The eruption times of premolars after physiological resorption of primary tooth roots given in the literature and those obtained by the author converge. After pathological resorption of primary tooth roots and rarefying osteitis with interruption of the lamina dura, vertical development occurs significantly sooner (p less than 0,01). 3. The sequence of eruption of the premolars can be altered after pathological resorption of primary tooth roots.

Animals↗