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A NOVEL EPIPHYTIC CYANOBACTERIAL SPECIES FROM THE GENUS BRASILONEMA CAUSING DAMAGE TO EUCALYPTUS LEAVES 1
Author(s) -
Aguiar Rosane,
Fiore Marli Fatima,
Franco Maione Wittig,
Ventrella Marília Contin,
Lorenzi Adriana Sturion,
Vanetti Cláudia A.,
Alfenas Acelino Couto
Publication year - 2008
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.2008.00584.x
Subject(s) - biology , epiphyte , cyanobacteria , botany , photosynthesis , 16s ribosomal rna , eucalyptus , phylogenetic tree , bacteria , gene , biochemistry , genetics
A cyanobacterial mat colonizing the leaves of Eucalyptus grandis was determined to be responsible for serious damage affecting the growth and development of whole plants under the clonal hybrid nursery conditions. The dominant cyanobacterial species was isolated in BG‐11 medium lacking a source of combined nitrogen and identified by cell morphology characters and molecular phylogenetic analysis (16S rRNA gene and cpc BA‐IGS sequences). The isolated strain represents a novel species of the genus Brasilonema and is designated Brasilonema octagenarum strain UFV‐E1. Thin sections of E. grandis leaves analyzed by light and electron microscopy showed that the B. octagenarum UFV‐E1 filaments penetrate into the leaf mesophyll. The depth of infection and the mechanism by which the cyanobacterium invades leaf tissue were not determined. A major consequence of colonization by this cyanobacterium is a reduction in photosynthesis in the host since the cyanobacterial mats decrease the amount of light incident on leaf surfaces. Moreover, the cyanobacteria also interfere with stomatal gas exchange, decreasing CO 2 assimilation. To our knowledge, this is the first report of an epiphytic cyanobacterial species causing damage to E. grandis leaves.