Antioxidant activity and induction of mechanisms of resistance to stresses related to the inoculation with Azospirillum brasilense

• Published in: Archives of microbiology Vol. 200; no. 8; pp. 1191 - 1203
• Main Authors: Fukami, Josiane, Ollero, Francisco Javier, de la Osa, Clara, Valderrama-Fernández, Rocio, Nogueira, Marco Antonio, Megías, Manuel, Hungria, Mariangela
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2018; Springer Nature B.V
• Subjects: Abscisic acid; Abscisic Acid - metabolism; Acetic acid; Antioxidants; Antioxidants - metabolism; Ascorbic acid; Azospirillum brasilense; Azospirillum brasilense - metabolism; Biochemistry; Biomedical and Life Sciences; Biotechnology; Catalase; Catalase - metabolism; Cell Biology; Corn; Cyclopentanes - metabolism; Ecology; Growth conditions; Growth stage; Indoleacetic acid; Indoleacetic Acids - metabolism; Inoculation; Jasmonic acid; L-Ascorbate peroxidase; Leaves; Life Sciences; Malondialdehyde; Malondialdehyde - metabolism; Metabolites; Microbial Ecology; Microbiology; Original Paper; Oxylipins - metabolism; Peroxidase; Plant Leaves - enzymology; Plant protection; Plant Roots - enzymology; Plants; Roots; Salicylic acid; Salicylic Acid - metabolism; Sodium chloride; Stress, Physiological; Superoxide dismutase; Superoxide Dismutase - metabolism; Zea mays; Zea mays - enzymology; Zea mays - metabolism; Zea mays - microbiology; ABA; Systemic acquired resistance; Salicylic acid; Antioxidant enzymes; AIA; L; Induced systemic resistance; Jasmonic acid; Zea mays L
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-018-1535-x

We investigated the effects of
Azospirillum brasilense
strains Ab-V5 and Ab-V6 in the induction of mechanisms of systemic acquired resistance (SAR) and induced system resistance (ISR) on maize (
Zea mays
L.) plants. Under normal growth conditions, the treatments consisted of the standard inoculation of cells at sowing, and leaf spray of cells or their metabolites at the V2.5 growth stage; under saline stress (170 mM NaCl), the treatment consisted of standard single and co-inoculation of
A. brasilense
and
Rhizobium tropici
. The main compounds in the
Azospirillum
metabolites were identified as indole-3-acetic acid (IAA) and salicylic acid (SA). Under normal conditions,
A. brasilense
cells applied at sowing or by leaf spray increased the activities of catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) in leaves, and of ascorbate peroxidase (APX) in roots; however, interestingly, in general the highest activities were observed by leaf spray of metabolites. Under normal conditions, the highest levels of salicylic acid (SA) and jasmonic acid (JA) were achieved in leaves by leaf spray of metabolites, of SA in roots by leaf spray of cells, and of JA in roots by standard inoculation and leaf spray of metabolites. Under saline stress, plant protection occurred via SA and abscisic acid (ABA), but not JA. In general, inoculation resulted in further increases in SA in leaves and roots, and ABA in leaves. We hypothesize that
A. brasilense
confers protection to maize plants by simultaneous induction of JA and SA pathways, and, under saline stressing conditions, by SA and ABA pathways.