UPDATE 2-BlackBerry takes a knock as cybersecurity revenue drop clouds automotive demand

(Adds details, background) Sept 27 (Reuters) - Canada's BlackBerry Ltd on Tuesday reported a fall in cybersecurity revenue for the second quarter, as customers reined in spending due to an uncertain macroeconomic environment, sending its shares down about 3% in extended trading. The company has also been facing tough competition from Microsoft Corp , Citrix Systems and International Business Machines in the security software segment, with revenue in the unit falling 7.5% to $111 million from a year ago. The company said in an earnings call that cybersecurity segment revenue in the third quarter is expected to be flat year-on-year. However, revenue at the company's Internet of things (IoT) unit, which includes the QNX software for automotive customers, rose about 28% to $51 million as it signed up more customers. BlackBerry's QNX software is now embedded in over 215 million vehicles worldwide, helped by surging demand for electric vehicles and connected-car technologies. The company recently added global carmakers such as Ford Motor , General Motors , Hyundai Motor , to its already strong client list of BMW , Honda Motor , Mercedes-Benz and Toyota Motor . BlackBerry in June said that a deal to sell its patents primarily related to mobile devices, messaging and wireless networking for $600 million to a special purpose vehicle has been delayed. Total revenue fell 4% to $168 million for the quarter ended Aug. 31, compared with a consensus estimate of $166.7 million, according to IBES data from Refinitiv. Excluding items, the company posted a loss of 5 cents per share, narrower than analysts' expectations of loss of 7 cents. (Reporting by Akash Sriram in Bengaluru; Editing by Sriraj Kalluvila and Shailesh Kuber)