Change in biochemical parameters of Persian oak (Quercus brantii Lindl.) seedlings inoculated by pathogens of charcoal disease under water deficit conditions

• Published in: Trees (Berlin, West) Vol. 32; no. 6; pp. 1595 - 1608
• Main Authors: Ghanbary, Ehsan, Kouchaksaraei, Masoud Tabari, Guidi, Lucia, Mirabolfathy, Mansoureh, Etemad, Vahid, Sanavi, Seyed Ali Mohammad Modarres, Struve, Daniel
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-12-2018; Springer Nature B.V
• Subjects: Agriculture; Ammonia; Antioxidants; Ascorbic acid; Biochemical characteristics; Biochemistry; Biomedical and Life Sciences; Catalase; Charcoal; Chitinase; Chlorophyll; Disease; Drought; Electrolyte leakage; Foliage; Forestry; Forests; Fungi; Glutathione; Glutathione reductase; Hydrogen peroxide; Inoculation; L-Ascorbate peroxidase; Life Sciences; Malondialdehyde; Moisture stress; Oak; Original Article; Pathogens; Peroxidase; Phenylalanine; Plant Anatomy/Development; Plant growth; Plant Pathology; Plant Physiology; Plant Sciences; Proline; Proteins; Quercus brantii; Seedlings; Soil moisture; Soil stresses; Sugar; Superoxide dismutase; Water deficit; Water stress; Antioxidants; Chitinase; Proline; Phenolic compounds; Charcoal disease; ROS
• ISSN: 0931-1890; 1432-2285
• DOI: 10.1007/s00468-018-1736-6

Key message
Drought alone or in combination with charcoal disease pathogens led to modifications in some biochemical characteristics of Persian oak seedlings. Drought conditions enhances the effects of charcoal fungus with effects at biochemical level.
Charcoal disease is one of the common diseases in oak forest of Zagros in western Iran that has increased in the recent years. The disease is associated with abiotic stress, especially drought, and contributes to the decline of Persian oak (
Quercus brantii
Lindl.), the major oak species in this forest association. Persian oak seedlings were exposed to a factorial combination of two irrigation levels and inoculation with either
Biscogniauxia mediterranea
or
Obolarina persica
(agents of charcoal disease). Proline, total soluble sugar and soluble protein contents in seedling foliage were increased in response to charcoal pathogen inoculation, especially when combined with water stress, while starch, chlorophyll
a
 + 
b
and carotenoid contents strongly declined. Pathogen inoculation stimulated malondialdehyde content, electrolyte leakage, and hydrogen peroxide and superoxide radical contents in oak leaves, and were increased by water stress. The combination of charcoal disease agents and water stress increased peroxidase and superoxide dismutase activity while, for catalase and ascorbate peroxidase activities, the interaction between the two factors of variability was not significantly increased. Ascorbate peroxidase activity was at maximum level in seedlings infected with
O. persica
independently of water stress. Glutathione reductase had the highest activity in inoculated seedlings under soil moisture stress while those under higher soil moisture levels, the enzyme was increased only when inoculated with
O. persica
. Contents of non-enzymatic antioxidants including ascorbic acid and glutathione increased in response to combined pathogen inoculation and water stress and was higher when seedlings were inoculated with
O. persica
than with
B. mediterranea
. Chitinase activity significantly increased because of pathogen inoculation. Furthermore, foliar phenylalanine ammonia lyase activity was higher under all treatment combinations, as compared to the controls. The effects of
B. mediterranea
or
O. persica
pathogens on foliar biochemical responses of
Q. brantii
seedlings were more severe under water-stress and it was more sensitive to
B. mediterranea
than
O. persica
.