TITLE:
Diversity among Isolates of the Tangerine Pathotype of Alternaria alternata
AUTHORS:
Andréa Celina Ferreira Demartelaere, Luciana Cordeiro do Nascimento, Cristina O. Marinho, Marciano Costa Nunes, Patrícia Clemente Abraão, Rommel S. S. Gomes, Mônica Danielly de Mello Oliveira, Larissa Almeida, Mirelly M. Porcino, Caroline Vargas e Silva, Wilza C. O. Souza
KEYWORDS:
Citrus tangerine, Alternaria Brown Spot, Fungal Variability, Environment Factors, ISSR Markers
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.2,
January
25,
2018
ABSTRACT: The tangerine pathotype of Alternaria alternata is the aetiological agent of Alternaria brown spot on
tangerines. In the state of Paraíba, Brazil, its occurrence on “Dancy” tangerine trees is associated with genetic aspects as well as the influence
of environmental conditions on reproduction and dissemination within and between
populations. The aim of the present study was to evaluate the diversity of isolates
of this pathogen using morphophysiological and molecular markers. For the analysis
of mycelial growth and sporulation, 30 isolates from different locations
were examined at 24-hour intervals until the seventh day, when the spores were quantified.
The 30 isolates were characterised based on molecular markers
(ISSR) and genetic similarity (Jaccard index). A factor arrangement was used: 30
isolates, four media (ODA, PDA, LEA and V8), three light regimes (continuous dark,
alternating light and continuous light) and three temperatures (15°C, 25°C and 35°C),
with 12 repetitions. Groups 1, 2 and 3 presented low genetic variability. Group
4 showed high genetic variability of the isolates obtained from the
Massaranduba (state of Paraíba-Brazil) producing region and higher mycelial
growth and sporulation of A. alternata.
The continuous light regime and the temperature 25°C in PDA and V8 media were
the ideal conditions for the mycelial growth and sporulation, respectively, of
the isolates of A. alternata.