PERSONAL DE APOYO
MASCIARELLI Oscar Alberto
artículos
Título:
Endophytic bacteria in sunflower (Helianthus annuus L.): isolation, characterization, and production of jasmonates and abscisic acid in culture medium
Autor/es:
G. FORCHETTI & O. MASCIARELLI & S. ALEMANO & D. ALVAREZ &
Revista:
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
Referencias:
Año: 2007 p. 1145 - 1152
ISSN:
0175-7598
Resumen:
Abstract
This study was designed to isolate and characterize
endophytic bacteria from sunflower (Helianthus annuus)
grown under irrigation and water stress (drought) conditions,
to analyze growth of isolated bacteria under drought
condition, and to evaluate the ability of bacteria isolated
from plants cultivated under drought to produce jasmonates
(JAs) and abscisic acid (ABA). Bacteria were isolated from
soil samples collected when sunflower plants were at the
end of the vegetative stage. A total of 29 endophytic strains
were isolated from plants grown under irrigation or drought
condition. Eight strains (termed SF1 through SF8) were
selected based on nitrogen-fixing ability. All eight strains
showed positive catalase and oxidase activities; five strains
(SF2, SF3, SF4, SF5, SF7) solubilized phosphates; none of
the strains produced siderophores. Strains SF2, SF3, SF4,
and SF5, the ones with the highest phosphate solubilization
ability, strongly inhibited growth of the pathogenic fungi
Verticillum orense and Sclerotinia sclerotiorum but had less
inhibitory effect on Alternaria sp. Among the eight strains,
SF2 showed 99.9% sequence homology with Achromobacter
xiloxidans or Alcaligenes sp., while the other seven
showed 99.9% homology with Bacillus pumilus. Strains
SF2, SF3, and SF4 grown in control medium produced
jasmonic acid (JA), 12-oxo-phytodienoic acid (OPDA), and
ABA. These three strains did not differ in amount of JA or
OPDA produced. ABA content was higher than that of JA,
and production of both ABA and JA increased under
drought condition. The characteristics of these isolated
bacterial strains have technological implications for inoculant
formulation and improved growth of sunflower crops.
Keywords Sunflower . PGPR . Jasmonates . Abscisic acid
