Sayyiduna Imran bin Husayn (may Allah be pleased with him) said: When Sayyiduna Ali (may Allah be pleased with him) prevailed over the people of Basrah, he began leading them in prayer according to the prayer of our Prophet (peace and blessings be upon him): he would say the takbir when bowing, the takbir when raising his head, the takbir when prostrating, and the takbir when standing up after the two rak'ahs.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15654