الفهرس 
Endophytic microorganismsOnly 14 pages are availabe for public view
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Abstract
All kinds of microorganisms like fungi, bacteria and
actinomycetes can survive inside plants as endophytes and protect
their host from adverse conditions and infectious agents by several
mechanisms. With the aim of studying the biodiversity and
antagonistic potential of endophytes against some wheat pathogenic
fungi to control some wheat diseases and improve its growth,
endophytes were isolated from 15 healthy different plants
(medicinal plants ’’basil, green onion, green pepper, mint, roselle,
tagetes, watercress and white radish’’ and common plants ’’corn,
cotton, jew’s mallow, marrow, okra, wheat and tomato’’) collected
from El-Qalyubia ’’El-Qanatir El-Khairiya’’ and El-Fayoum
governorates.
All the studied plants found to be resided with endophytic fungi
in their different organs tissues but endophytic bacteria and
endophytic actinomycetes reported only in 6 and 2 of the studied
plants, respectively. Sixty-two endophytic fungal species belonging
to 18 genera and 3 morphospecies of mycelia sterilia group were
identified according to morphological methods, while 7 endophytic
bacterial species belonging to 6 genera and 2 endophytic
actinomycetes species belonging to 2 genera were identified by
molecular methods. Out of all the identified endophytic fungi,
Aspergillus, Fusarium, Penicillium, Alternaria, Acremonium and
mycelia sterilia were with a predominance during the isolation and Aspergillus had the highest relative frequency in all the studied
plants but not found in green pepper. Nine wheat pathogenic fungi
were obtained from naturally infected wheat plants grown in ElQalyubia (El-Qanatir El-Khairiya) governorates and were identified
as Alternaria alternata, Alternaria cichorii, Alternaria dianthi,
Alternaria sonchi, Aspergillus petrakii, Curvularia penniseti,
Fusarium oxysporum, Fusarium semitectum and Fusarium solani.
Screening of all the identified endophytic species for in vitro
antagonistic activity against nine wheat pathogenic fungi was
carried out using dual culture methods. from this experiment
results, seven endophytic antagonists were selected with respect to
their potent activity against 4 of wheat pathogenic fungi. The
inhibition percentages were as the following: Aspergillus melleus
gave 70 % with Alternaria dianthi, Penicillium chrysogenum and
dark septate sterile mycelium isolate gave 69.57 % and 56.52 %,
respectively with Aspergillus petrakii; while, Aspergillus unguis
and Cladosporium cladosporioides gave 74.29 % and 60 %,
respectively with Fusarium oxysporum. Fusarium subglutinans and
Streptomyces rochei showed percentages of 72.97 % and 51.35 %,
respectively with Fusarium semitectium. The identification of the
six selected endophytic antagonistic fungi were confirmed by the
molecular methods based on their ITS-rDNA sequences.
Enzymatic index of six tested enzymes by the selected seven species revealed that only cellulase was produced by all the selected
species which associated with the colonization processes.
The role of the selected endophytic antagonists to control root
rot and leaves diseases development and to stimulate growth of
wheat plants under greenhouse conditions was studied. Root rot
disease caused by Aspergillus petrakii, Fusarium oxysporum and
Fusarium semitectium were reduced by seeds coating method by
different selected endophytes. The lowest root rot severity
percentage was observed with dark septate sterile mycelium isolate
(15.56 %), Cladosporium cladosporioides (6.67 %) and Fusarium
subglutinans & Streptomyces rochei (20 %) in soil infested with
Aspergillus petrakii, Fusarium oxysporum and Fusarium
semitectium, respectively.
Wheat plants leaves diseases incidence caused by Alternaria
dianthi and Aspergillus petrakii were also reduced by spraying
leaves with Aspergillus melleus and dark septate sterile mycelium
isolate with percentages of 12.50 % and 16.67 %, respectively. The
results showed that some wheat plants growth parameters were
promoted in endophytes-treated plants compared to their respective
control.