TY - JOUR
T1 - Endophytic bacteria in rice seeds inhibit early colonization of roots by Azospirillum brasilense
AU - Bacilio-Jiménez, M.
AU - Aguilar-Flores, S.
AU - Del Valle, M. V.
AU - Pérez, A.
AU - Zepeda, A.
AU - Zenteno, E.
N1 - Funding Information:
Thanks are due to Tomas Cruz and Diana Millan, from the Departamento de Biologia Celular y Tisular, UNAM, Mexico. This work was financed in part by DEPI-IPN; CONACyT (27609M), DGAPA-UNAM (PAPIIT IN 224598) and ECOS Mexico–France (M97B05).
PY - 2001
Y1 - 2001
N2 - From the rhizoplane of Oryza sativa, vars. Morelos A-88 and Apatzingan, rice plantlets, we isolated two bacterial strains: Corynebacterium flavescens and Bacillus pumilus. By scanning electron microscopy, endophytic bacteria were frequently identified at the base of secondary roots, between the epidermis and the mucilaginous layer. Endophytes were also identified in the intercellular spaces when the mucilaginous layer was disrupted. These endophytic bacteria were not pathogenic when assayed on tobacco leaves. Plantlets from the rice varieties cultured gnotobiotically under hydroponic conditions were inoculated with Azospirillum brasilense, 6-81 or UAP-154 strains. Control experiments were performed using non-inoculated plantlets or plantlets previously treated with nalidixic acid. Comparison of the length of inoculated or nalidixic acid-treated plantlets, with non-inoculated plantlets revealed a significant (p < 0.05) promotion of the growth of the shoots at 15 days of culture in plantlets colonized exclusively by endophytes. A. brasilense seems to be excluded from the rhizoplane by the endophytic bacteria, suggesting that endophytes compete with Azospirillum, and also that A. brasilense inhibits growth of rice. Our results indicate that endophytic bacteria could participate in the growth and development of rice plants.
AB - From the rhizoplane of Oryza sativa, vars. Morelos A-88 and Apatzingan, rice plantlets, we isolated two bacterial strains: Corynebacterium flavescens and Bacillus pumilus. By scanning electron microscopy, endophytic bacteria were frequently identified at the base of secondary roots, between the epidermis and the mucilaginous layer. Endophytes were also identified in the intercellular spaces when the mucilaginous layer was disrupted. These endophytic bacteria were not pathogenic when assayed on tobacco leaves. Plantlets from the rice varieties cultured gnotobiotically under hydroponic conditions were inoculated with Azospirillum brasilense, 6-81 or UAP-154 strains. Control experiments were performed using non-inoculated plantlets or plantlets previously treated with nalidixic acid. Comparison of the length of inoculated or nalidixic acid-treated plantlets, with non-inoculated plantlets revealed a significant (p < 0.05) promotion of the growth of the shoots at 15 days of culture in plantlets colonized exclusively by endophytes. A. brasilense seems to be excluded from the rhizoplane by the endophytic bacteria, suggesting that endophytes compete with Azospirillum, and also that A. brasilense inhibits growth of rice. Our results indicate that endophytic bacteria could participate in the growth and development of rice plants.
KW - Azospirillum brasilense
KW - Bacillus pumilus
KW - Corynebacterium flavescens
KW - Endophytic bacteria
KW - Oryza sativa seeds
UR - http://www.scopus.com/inward/record.url?scp=0035121927&partnerID=8YFLogxK
U2 - 10.1016/S0038-0717(00)00126-7
DO - 10.1016/S0038-0717(00)00126-7
M3 - Artículo
SN - 0038-0717
VL - 33
SP - 167
EP - 172
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
IS - 2
ER -