Keywords:
molecular characterization
plant diseases
bacteria
phytoplasmas
pathogen-elimination
diagnostic
Phytoplasmas and bacteria presence is worldwide spread in several
ecosystems: research performed are aimed to verify the presence of
bacteria and the definition of association with phytoplasma
presence of morphological and functional anomalies in plants of
different species by phytoplasma molecular identification.
Classical isolation and morpho-serological and molecular
identification identification of these pathogens are carried out.
Beside the classification based on ribosomal gene 16S research to
verify the taxonomic value of other phytoplasma genes are carried
out. In particular variability of genes coding for important
pathogen functions such as those related to the immunodominant
membrane complex (Amp) that are inportant in phytoplasma insect
transmission and of tuf gene related to basic phytoplasma
proteinosinthesis. Further researches are carried out to verify the
taxonomic relevance of rpS3 and SecY genes together with 16S for
the production of diagnostic tools that can be emplyoed for the
detection and identification of quarantine phytoplasmas. Sudies on
phytoplasma transmission by new insect vectors species and to
verify seed transmissibility are also performed.
Research to study the effectiveness of molecules different from
antibiotics for their activity against phytoplasmas are carried out
on in vivo and in vitro grown shoots towards the improvement of
phytoplasama disease managment. Epidemiological studies using
molecular markers are also carried out to determine the cycles of
the most important phytoplasma and bacterial diseases (grapevine,
fruit trees, ornamental and forest trees).
The presence of bacteria and phytoplasmas is increasingly
widespread in many ecosystems. The alterations associated with the
presence of these phytopathogenic prokaryotes are different and
purpose of the research is to verify the binding of them with
morpho-functional abnormalities present in plant species important
from an economic point of view or biologically. Visual plant
examination will be carried out and appropriate laboratory
investigations in order to identify bacteria and phytoplasmas and
determine the main bio-morphologic characteristics of infected
plants. Such research will take advantage of the most advanced
knowledge in the field of biotechnology, taking into account
epidemiological and economic aspects related to this type of
diseases: biological assays, isolation of axenic cultures,
techniques of optical and electron microscopy, use of molecular
probes, gene amplification (PCR), restriction fragment length
polymorphism analyses (RFLP) and sequencing of nucleic acids . The
study will involve important plant species such as hardwoods (elm,
willow, Acacia, chestnut, etc.) and evergreen coniferous trees like
pine and fir trees on which to date phytoplasmas were not clearly
related to specific syndromes (' Candidatus Phytoplasma pini '). It
will be taken into consideration also other species such as maize,
prickly pear, Forsythia, rose, cyclamen, sweet pepper, silene,
cassava, oil palm and others detected during the research. Also
herbaceous or shrub plant disease will be studied since they may be
sources of infection for other agronomically relevant species.
Search will be also carried our on potential natural vectors such
as psyllids and leafhoppers. The research material is subjected to
extraction of nucleic acids, nested-PCR with primers specific for
phytoplasmas ribosomal gene and RFLP analysis and identification of
phytoplasmas is carried out through comparison with samples of
phytoplasmas already identified. Other non-conserved regions of the
genome of phytoplasma genes such as tuf, rp, amp and others
will be studied when necessary for strain identification. Sequence
comparison will be carried out with the phytoplasma strains
reported in the literature and whose sequences are available in
GenBank, and other databases. Surveys will be carried out to detect
the presence of insect potential natural carriers of
phytoplasmas identified from time to time. In addition, research
will be carried out to confirm the transmissibility of phytoplasmas
through the seed in order to validate and confirm preliminary
observations on some species such as alfalfa, tomato, corn,
sesami and lime. To verify the possibility of elimination of
phytoplasma from infected plants in some trials will be carried out
in a host-pathogen systems under controlled environment
(micropropagation). Different substances such as RIPs, therpenes
and plasma of different origin will be tested. Visual control
and through gene amplification assay with nested PCR to check
for the presence of DNA of the pathogen after default periods from
the beginning of treatment will be performed. Viability of
phytoplasmas will also be verified in case of positive results to
molecular assays in treated plants. Similar trials using also BCAs
will be carried out on woody plants (fruit trees and grapevine) in
order to verify the practical application of these molecules in
containment of bacterial diseases as well.