scholarly journals Powdery Mildew-Induced Hormonal and Photosynthetic Changes in Barley Near Isogenic Lines Carrying Various Resistant Genes

2020 ◽  
Vol 21 (12) ◽  
pp. 4536 ◽  
Author(s):  
Diana Saja ◽  
Anna Janeczko ◽  
Balázs Barna ◽  
Andrzej Skoczowski ◽  
Michał Dziurka ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Post Inoculation ◽  
Near Isogenic Lines ◽  
Leaf Reflectance ◽  
Isogenic Lines ◽  
Fluorescence Measurements ◽  
Resistant Genes ◽  
Psii Activity

The present work focused on the characterization of some physiological mechanisms activated upon powdery mildew inoculation of the susceptible barley cultivar Ingrid and its near-isogenic lines (NILs) carrying various resistant genes (Mla, Mlg and mlo). After inoculation with Blumeria graminis f. sp. hordei (Bgh), measurements of leaf reflectance and chlorophyll a fluorescence were performed 3 and 7 day post-inoculation (dpi), while hormone assays were made 7 dpi. Bgh-inoculated resistant genotypes were characterized by lowered leaf reflectance parameters that correlated with carotenoids (CRI) and water content (WBI) in comparison to inoculated Ingrid. The PSII activity (i.e., Fv/Fm, ETo/CSm and P.I.ABS) strongly decreased in susceptible Ingrid leaves when the disease symptoms became visible 7 dpi. In Mla plants with visible hypersensitive spots the PSII activity decreased to a lesser extent. Inoculation resulted in a very slight decrease of photosynthesis at later stage of infection in Mlg plants, whereas in resistant mlo plants the PSII activity did not change. Chlorophyll a fluorescence measurements allowed presymptomatic detection of infection in Ingrid and Mla. Changes in the homeostasis of 22 phytohormones (cytokinins, auxins, gibberellins and the stress hormones JA, SA and ABA) in powdery mildew inoculated barley are discussed in relation to resistance against this biotrophic pathogen.

scholarly journals Lipoxygenase activities during development of root and nodule of soybean

2004 ◽  
Vol 39 (7) ◽  
pp. 625-630 ◽  
Author(s):  
Tatiana Góes Junghans ◽  
Maria Goreti de Almeida Oliveira ◽  
Maurilio Alves Moreira
Keyword(s):  
Growth And Development ◽  
Root Formation ◽  
Lipoxygenase Activity ◽  
Post Inoculation ◽  
Isogenic Line ◽  
Near Isogenic Line ◽  
Near Isogenic Lines ◽  
Isogenic Lines ◽  
Bradyrhizobium Elkanii ◽  
Over Time

The objective of this work was to evaluate root and nodule soybean lipoxygenases in Doko cultivar and in a near isogenic line lacking seed lipoxygenases, inoculated and uninoculated with Bradyrhizobium elkanii. The lipoxygenase activities from roots collected at 3, 5, 9, 13, 18 and 28 days post-inoculation and from nodules collected at 13, 18 and 28 days post-inoculation were measured. The pH-activity profiles from root and nodules suggested that the lipoxygenases pool expressed in these organs from Doko cultivar and triple-null near isogenic lines are similar. The root lipoxygenase activity of Doko and triple-null lines, inoculated and uninoculated, reduced over time. The highest lipoxygenase activity observed at the beginning of root formation suggests the involvement of this enzyme in growth and development of this organ. However, for nodules an expressive increase of lipoxygenase activity was noticed 28 days post-inoculation. Root and nodule showed, at least, two mobility groups for lipoxygenases in immunoblottings, with approximately 94 and 97 kDa.

scholarly journals Chlorophyll a fluorescence as an indicator of water stress in Calophyllum brasiliense

2020 ◽  
Vol 48 (1) ◽  
pp. 210-220 ◽  
Author(s):  
Lucas C. REIS ◽  
Silvana P.Q. SCALON ◽  
Daiane DRESCH ◽  
Andressa Caroline FORESTI ◽  
Cleberton C. SANTOS ◽  
...  
Keyword(s):  
Water Deficit ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Stress Condition ◽  
Water Status ◽  
Photosynthetic Apparatus ◽  
Stress Indicator ◽  
Fluorescence Measurements ◽  
Calophyllum Brasiliense ◽  
And Function

The objective of this study was to evaluate chlorophyll a fluorescence as a stress indicator in Calophyllum brasiliense Cambess seedlings grown with different concentrations of abscisic acid (ABA) under intermittent water deficit condition: daily irrigation without ABA (I); daily irrigation + 10 μM ABA (I 10); daily irrigation + 100 μM ABA (I 100); suspension of daily irrigation without ABA (SI); suspension of daily irrigation + 10 μM ABA (SI 10) and  suspension of daily irrigation + 100 μM ABA (SI 100). The intermittent water deficit reduces water status and impairs the photochemical apparatus functioning and seedling quality. The fluorescence measurements helped identify the stress condition of water deficit in the cultivation of C. brasiliense and the beneficial effect of the application of 10 μM of ABA in minimizing stress and facilitating the recovery of seedlings after re-irrigation, while maintaining the integrity and function of the photosynthetic apparatus.

scholarly journals Linked, if Not the Same, Mi-1 Homologues Confer Resistance to Tomato Powdery Mildew and Root-Knot Nematodes

2011 ◽  
Vol 24 (4) ◽  
pp. 441-450 ◽  
Author(s):  
Alireza Seifi ◽  
Isgouhi Kaloshian ◽  
Jack Vossen ◽  
Daidi Che ◽  
Kishor K. Bhattarai ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Powdery Mildew ◽  
Gene Cluster ◽  
Chromosome 6 ◽  
R Genes ◽  
Near Isogenic Lines ◽  
Root Knot Nematodes ◽  
Isogenic Lines ◽  
Tomato Chromosome ◽  
Tomato Powdery Mildew

On the short arm of tomato chromosome 6, a cluster of disease resistance (R) genes have evolved harboring the Mi-1 and Cf genes. The Mi-1 gene confers resistance to root-knot nematodes, aphids, and whiteflies. Previously, we mapped two genes, Ol-4 and Ol-6, for resistance to tomato powdery mildew in this cluster. The aim of this study was to investigate whether Ol-4 and Ol-6 are homologues of the R genes located in this cluster. We show that near-isogenic lines (NIL) harboring Ol-4 (NIL-Ol-4) and Ol-6 (NIL-Ol-6) are also resistant to nematodes and aphids. Genetically, the resistance to nematodes cosegregates with Ol-4 and Ol-6, which are further fine-mapped to the Mi-1 cluster. We provide evidence that the composition of Mi-1 homologues in NIL-Ol-4 and NIL-Ol-6 is different from other nematode-resistant tomato lines, Motelle and VFNT, harboring the Mi-1 gene. Furthermore, we demonstrate that the resistance to both nematodes and tomato powdery mildew in these two NIL is governed by linked (if not the same) Mi-1 homologues in the Mi-1 gene cluster. Finally, we discuss how Solanum crops exploit Mi-1 homologues to defend themselves against distinct pathogens.

scholarly journals DAYTIME VARIATIONS OF CHLOROPHYLL A FLUORESCENCE IN PAU D'ALHO SEEDLINGS

2016 ◽  
Vol 40 (6) ◽  
pp. 1023-1030 ◽  
Author(s):  
Marcos Antonio Bacarin ◽  
Emanuela Garbin Martinazzo ◽  
Daniela Cassol ◽  
Antelmo Ralph Falqueto ◽  
Diolina Moura Silva
Keyword(s):  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Photochemical Efficiency ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Active Radiation ◽  
High Radiation ◽  
Active Radiation ◽  
Fluorescence Measurements ◽  
Subsequent Decrease ◽  
Modulated Fluorescence

ABSTRACT Analysis of transient and modulated fluorescence of chlorophyll a were made at one-hour intervals during an eight-hour period starting at 07:30h aiming to study mechanisms of photoprotection against high radiation and temperature in Gallesia integrifolia plants. Seeds were germinated inside plastic pots containing soil as substrate. At 120 days after emergence, chlorophyll fluorescence measurements were performed using Handy-PEA and FMS2 fluorometers. During the course of a day, an increase and a subsequent decrease in temperature and in photosynthetic active radiation were observed until 12:30h. Changes in transient kinetic curves of chlorophyll a fluorescence were identified. This resulted in changes in JIP test parameters. An increase during the period of high radiation and temperature may be stressed in relation to variables related to dissipation flux and appearance of positive -K and -L bands. Considering the modulated fluorescence, high values of non-photochemical quenching coefficients associated with lower values of effective photochemical efficiency of the photosystem II (FV'/ FM') and current photochemical efficiency of PSII (φPSII) could be observed during early morning. This was probably the result of an inhibition of the biochemical phase of photosynthesis. It can be concluded that Gallesia integrifolia decrease its photochemical activity with the increase in the photosynthetic active radiation, demonstrating a photoinhibitory effect under high irradiance conditions, but without irreversible damages to the photosynthetic apparatus.

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