Another chief suspect is theology lecturer Adil Oksuz, whom Turkish officials accuse of being the so-called “imam” of the plot by coordinating the action on the ground in Turkey with Gulen.
Businessman Kemal Batmaz is meanwhile accused of assisting Oksuz.
Oksuz was detained following the coup’s defeat, but was subsequently released and is now on the run.
Batmaz led the line of suspects into court wearing a cream shirt with black trousers followed by Ozturk wearing a grey shirt and black trousers.
Chief of Staff General Hulusi Akar and other senior commanders were held hostage at the base during the coup attempt before they were freed on the morning on July 16.
The base was seen as the coup plot headquarters where commands were given for the F-16 fighter jets to attack and fly them above the capital.
The Turkish parliament was bombed three times by F-16s.
– Largest courtroom –
The trial is taking place in Turkey’s largest courtroom established inside a prison complex in Sincan to hear coup-related trials and has space for more than 1,500 people.
The deputy leader of the ruling Justice and Development Party (AKP), Hayati Yazici, told reporters the party made a request to be a co-litigant in the trial.
“Of course these putschists will be given the punishment they deserve,” Yazici added.
Erdogan, Akar and the main opposition Republican People’s Party (CHP) also applied to be litigants, Turkish media said.
The courtroom has previously hosted mass trials related to the coup bid including one which opened in February of 330 suspects accused of murder or attempted murder.
And in May, 221 suspects were put on trial accused of being the ringleaders of the failed coup.
There was heavy security including 1,130 security personnel inside and outside the courtroom, according to state-run news agency Anadolu, as well as snipers, armoured security vehicles and a drone.
The trial is one of several held across Turkey judging coup suspects, in the largest legal process in the country’s modern history.
Over 50,000 people have been arrested over alleged links to Gulen in a wide-scale crackdown under the state of emergency imposed following the coup.
500 prisoners were paraded with shouts for executions, in Erdogan’s latest show trials. Turkey is EU candidate.
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— Ari Murad (@AriMurad_) August 1, 2017