scholarly journals Annual variations in the microflora of some varieties of Finnish malting barley

1995 ◽  
Vol 4 (4) ◽  
pp. 407-418
Author(s):  
Tapani Tuominen ◽  
Heikki Rosenqvist
Keyword(s):  
Plant Hormone ◽  
Growing Season ◽  
Fungal Species ◽  
Consistent Difference ◽  
Malting Barley ◽  
Microbial Infection ◽  
Microbial Counts ◽  
Annual Variations ◽  
Average Rainfall ◽  
Indole 3 Acetic Acid

Three major Finnish malting barley varieties were studied for annual variations in the incidence of seed-derived fungi, bacteria and actinomycetes. In 1990-1992, 114 characterized fungal, 59 uncharacterized bacterial and 12 uncharacterized actinomycetal isolates were extracted from samples of seed intended for use in malting. When the yield of the plant hormone, indole-3-acetic acid (lAA), from enriched microbial cultures was weighed against the microbial biomass and the endogenous lAA concentration of the barley harvests, it was concluded that potential exists for bacterial lAA production in biologically significant amounts, given some minor annual variations. As expected from the average rainfall and temperature during the growing season, microbial counts in all cultivars were highest in 1992. Most of the fungal species found were of saphrophytic character, and field fungi were dominant in the samples. On the whole, microbial counts and spectra in all samples confirmed that each harvest of all cultivars was of good vigour and well suited for malting purposes. Strains of plant pathogenic character included species of Septoria nodorum (Berk) Berk, Drechlera teres (Sacc) Subraim & Jain, D. sorokiniana (Sacc) Subram & Jain and D. graminea (Rab.) Shoem. A consistent difference was noted in the microbial infection severities of the cultivars.

scholarly journals Biochemical and Genetic Bases of Indole-3-Acetic Acid (Auxin Phytohormone) Degradation by the Plant-Growth-Promoting Rhizobacterium Paraburkholderia phytofirmans PsJN

2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Raúl Donoso ◽  
Pablo Leiva-Novoa ◽  
Ana Zúñiga ◽  
Tania Timmermann ◽  
Gonzalo Recabarren-Gajardo ◽  
...  
Keyword(s):  
Energy Source ◽  
Gene Regulation ◽  
Acetic Acid ◽  
Plant Growth ◽  
Plant Hormone ◽  
Content Type ◽  
Gene Functions ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Indole 3 Acetic Acid

ABSTRACT Several bacteria use the plant hormone indole-3-acetic acid (IAA) as a sole carbon and energy source. A cluster of genes (named iac) encoding IAA degradation has been reported in Pseudomonas putida 1290, but the functions of these genes are not completely understood. The plant-growth-promoting rhizobacterium Paraburkholderia phytofirmans PsJN harbors iac gene homologues in its genome, but with a different gene organization and context than those of P. putida 1290. The iac gene functions enable P. phytofirmans to use IAA as a sole carbon and energy source. Employing a heterologous expression system approach, P. phytofirmans iac genes with previously undescribed functions were associated with specific biochemical steps. In addition, two uncharacterized genes, previously unreported in P. putida and found to be related to major facilitator and tautomerase superfamilies, are involved in removal of an IAA metabolite called dioxindole-3-acetate. Similar to the case in strain 1290, IAA degradation proceeds through catechol as intermediate, which is subsequently degraded by ortho-ring cleavage. A putative two-component regulatory system and a LysR-type regulator, which apparently respond to IAA and dioxindole-3-acetate, respectively, are involved in iac gene regulation in P. phytofirmans. These results provide new insights about unknown gene functions and complex regulatory mechanisms in IAA bacterial catabolism. IMPORTANCE This study describes indole-3-acetic acid (auxin phytohormone) degradation in the well-known betaproteobacterium P. phytofirmans PsJN and comprises a complete description of genes, some of them with previously unreported functions, and the general basis of their gene regulation. This work contributes to the understanding of how beneficial bacteria interact with plants, helping them to grow and/or to resist environmental stresses, through a complex set of molecular signals, in this case through degradation of a highly relevant plant hormone.

Determination of Plant Hormone Indole-3-Acetic Acid in Aqueous Solution

2012 ◽  
Vol 25 (1) ◽  
pp. 303-307 ◽  
Author(s):  
Jana Bulíčková ◽  
Romana Sokolová ◽  
Stefania Giannarelli ◽  
Beatrice Muscatello
Keyword(s):  
Aqueous Solution ◽  
Acetic Acid ◽  
Plant Hormone ◽  
Indole 3 Acetic Acid

Identification of IAA-regulated genes in Pseudomonas syringae pv. tomato strain DC3000

2021 ◽  
Author(s):  
Arnaud-Thierry Djami-Tchatchou ◽  
Zipeng Alex Li ◽  
Paul Stodghill ◽  
Melanie J. Filiatrault ◽  
Barbara N. Kunkel
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Acetic Acid ◽  
Stress Response ◽  
Pseudomonas Syringae ◽  
Plant Pathogen ◽  
Type Iii Secretion ◽  
Plant Hormone ◽  
Indole 3 Acetic Acid ◽  
Exogenous Iaa

The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 ( Pto DC3000). To learn more about the impact of IAA on regulation of Pto DC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta . Collectively the data indicate that IAA modulates many aspects of Pto DC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain Pto DC000 and one of its hosts, Arabidopsis thaliana . However, the mechanisms by which IAA impacts the biology of Pto DC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in Pto DC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.

THE EFFECTS OF AMOUNT AND DISTRIBUTION OF RAINFALL ON THE PROTEIN CONTENT OF WESTERN CANADIAN WHEAT

1942 ◽  
Vol 20c (4) ◽  
pp. 212-227 ◽  
Author(s):  
Allan E. Paull ◽  
J. Ansel Anderson
Keyword(s):  
Protein Content ◽  
Regression Coefficient ◽  
Growing Season ◽  
Minor Importance ◽  
Residual Variance ◽  
Average Effect ◽  
Average Rainfall ◽  
Unit Increase ◽  
Average Unit

Data for 14 yr. were used to determine the average effect of rainfall on the protein content of wheat grown at seven stations in the dry belt of southwestern Saskatchewan. Employing the concept of a regressional integral, and working with the rainfall for consecutive five-day intervals from April 1 to August 3, a curve was obtained which represents the change occurring during the growing season in the average regression coefficient (i.e., the average unit decrease in protein content per unit increase in rainfall). It was found that 34% of the residual variance for protein content can be ascribed to variations in rainfall. Above average rainfall during the growing season generally tends to reduce protein content, but this tendency is much more marked during April and early May, and during the latter part of July. These are also the periods during which average rainfall is lowest. The effect on protein content of precipitation occurring during the previous fall is of minor importance.

Evaluation of the level of N supply in maize hybrids at different nutritional levels

2010 ◽  
Vol 58 (Supplement 1) ◽  
pp. 89-94
Author(s):  
A. Ványiné Széles
Keyword(s):  
Active Ingredient ◽  
Growing Season ◽  
Vegetation Period ◽  
Maize Hybrids ◽  
Leaf Stage ◽  
Stochastic Correlation ◽  
Spad Value ◽  
N Supply ◽  
Average Precipitation ◽  
Average Rainfall

The aim of the research was to determine the effect of fertilisation and year on the SPAD value and on the dynamics of the SPAD value during the growing season.The results proved that the SPAD value steadily decreased over the growing season in a dry year, whereas it increased in a year with favourable precipitation. Fertilisation increased the SPAD values significantly (P<0.001). The significantly highest SPAD value, in both dry years and those with average rainfall, was achieved by applying 60 kg N ha −1 fertiliser active ingredient at the 6-leaf stage, and 120 kg N ha −1 at both the 12-leaf stage and the 50% silking stage.The correlation between fertilisation and SPAD values was greatly affected by the year, being closest in 2004 when there was an average precipitation supply, and weakest in 2007, the driest year. The correlation between the factors was weak at the 6-leaf stage, but became stronger as the vegetation period proceeded.As the growing season progressed, the SPAD values decreased in the dry year, but increased in the year with average precipitation supplies. Nutrient uptake was relatively intensive until the 12-leaf stage in the average year. In the dry year, the decrease in the SPAD value was the most intensive at the 50% silking stage.There was no stochastic correlation between the SPAD value measured at the 6-leaf stage and the yield, but the correlation between the two variables became stronger during the vegetation period.

On the Mechanism of Action of 2, 4-Dichlorophenoxyacetic Acid

1949 ◽  
Vol 2 (2) ◽  
pp. 154 ◽  
Author(s):  
PL Goldacre
Keyword(s):  
Mechanism Of Action ◽  
Enzyme Preparation ◽  
Plant Hormone ◽  
Structural Similarity ◽  
Economic Importance ◽  
Dichlorophenoxyacetic Acid ◽  
Crude Enzyme Preparation ◽  
Rate Limiting ◽  
Indole 3 Acetic Acid ◽  
Fundamental Mechanism

The use of synthetic plant growth-regulating compounds is of increasing economic importance in agriculture but little is known of their fundamental mechanism of action. The hormone-like character and general structural similarity of certain substituted aryl-acetates and -oxyacetates or their potential precursors (Zimmerman and Hitchcock 1941-42) to that of indole-3-acetic acid (LA.A.) suggest that these compounds may act indirectly by altering the activity of this natural plant hormone. Tang and Bonner (1947) have partially characterized an enzyme prepared from pea epicotyls (and referred to here as LA.A. oxidase) which oxidizes and inactivates LA.A. On adding 11 auxin analogues to a crude enzyme preparation they found no change in the rate of LA.A. inactivation. However, as these workers used a substrate (LA.A.) concentration that was rate-limiting, the only rate-change necessarily to be detected would have been a decrease due to competition with the substrate.

Assigning birds to geographic origin using feather hydrogen isotope ratios (δ2H): importance of year, age, and habitat

2012 ◽  
Vol 90 (6) ◽  
pp. 722-728 ◽  
Author(s):  
S. Haché ◽  
K.A. Hobson ◽  
M.-A. Villard ◽  
E.M. Bayne
Keyword(s):  
Hydrogen Isotope ◽  
Geographical Origin ◽  
Geographic Origin ◽  
Habitat Type ◽  
Growing Season ◽  
Global Network ◽  
Annual Variations ◽  
Sources Of Variation ◽  
Seiurus Aurocapilla ◽  
Hydrogen Isotope Ratios

In North America, gradients in the ratio of stable hydrogen isotopes in amount-weighted, growing-season mean precipitation (2H:1H; depicted as δ2Hp) form a largely latitude-sensitive isoscape that can be used to estimate the geographical origin of animals. Feathers are metabolically inert following growth and δ2Hf values retain information on geographical origins. However, there are important assumptions underlying this approach that can only be tested using birds of known origin. Here, we investigated sources of variation in δ2Hf measurements from Ovenbirds ( Seiurus aurocapilla (L., 1766)) associated with year, age class, feather type, season, and habitat type in New Brunswick, Canada. The observed δ2Hf generally followed that predicted from the Global Network of Isotopes in Precipitation database. However, we found a strong year × age interaction on δ2Hf. Season, habitat type, and feather type explained only a small portion of the overall variation in δ2Hf. These results show the advantages of using annual δ2Hp isoscapes and age-specific corrections when converting δ2Hp to δ2Hf. We submit that the interaction effect can be modeled by accounting for interannual variation in the amount of precipitation during the breeding season. These procedures will allow for more precise estimates of the geographical origin of individual birds, especially for studies conducted near oceanic coasts, which are subject to significant annual variations in growing season δ2Hp.

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