Thesis
Caracterización molecular de Streptomyeces spp. asociadas a la sarna común y evaluación in vitro de antagonistas nativos de la rizosfera de papa en Sinaloa
Autor
IB. RETE CORRAL, ANALILIA
Institución
Resumen
Sinaloa has stood as the largest potato producer in Mexico, the crop is located
mainly in irrigated areas of the northern region of the state and municipalities of
Guasave and Ahome generating an output of around 263 000 tons per year.,
However the potato crop is affected by a large number of diseases as common
scab of potato is caused by pathogenic species of Streptomyces. In the 2008-2009
growing cycle caused disease in the state, having a significant production losses,
affecting the quality and value in the market for this crop. No scientific papers at
national or state indicate that the pathogen of potato common scab is present, but
visiting the fields could be observed that the symptoms of common scab in potato
tubers in the region have characteristic symptoms of scabies caused by
Streptomyces scabies, Streptomyces acidiscabies and Streptomyces
turgidiscabies. It is suggested that this was due to the introduction to the area of
seed tubers infected with pathogenic species of Streptomyces. Therefore, this
paper arose from research that has aimed to characterize Streptomyces species
associated with common scab and evaluate native rhizosphere antagonists
against potato common scab in Sinaloa. Samples of symptomatic tubers and
potato rhizosphere were collected from 10 localities representing the Mumps area
of Sinaloa. A isolates with morphological characteristics of Streptomyces
underwent DNA extraction and PCR with primers that amplify genes pathogenicity
(txtAB and Nec1) associated with the common scab. Successfully detected by
PCR Streptomyces species associated with pathogenicity of tuber injury both
symptomatic and potato rhizosphere. Phylogenetic analysis of the sequences
obtained with the 16S gene and compared with those reported in the gene bank
indicated that our isolates have a 100% homology with Streptomyces acidiscabies
and Streptomyces scabies reported in the countries of Canada, China, USA,
Japan and Korea. Later tests were conducted 11 antagonism of bacterial isolates
obtained from the rhizosphere of potato crops in Sinaloa against Streptomyces
acidiscabies, four of the eleven bacterial isolates showed antagonistic activity in
vitro essay, Bacillus simplex, Bacillus megaterium, Streptomyces coelicolor and
Pseudomonas lini , resulting in the latter that had the highest antagonistic effect.
The data obtained during this research as the characterization of Streptomyces scabies and Streptomyces acidiscabies well as their antagonists in laboratory tests
will level the tone for testing biological control of potato scab in Sinaloa both
greenhouse and field.