ROME, June 24 (Reuters) - A plant operated by Leonardo in southern Italy will be closed for four months because of the knock-on effects of the crisis faced by Boeing , the Italian defence and aerospace group said on Monday.

However, Leonardo said that the plant in Grottaglie in the Puglia region had been selected for final assembly of the AW609 tilt-rotor aircraft in Italy, a boost for a site originally built for the Boeing 787 Dreamliner programme.

"Lower growth in the production and delivery of the Boeing 787 required a four-month plant shutdown to align production volumes with the short-term reduction in demand," the company said after a meeting with trade unions in Rome.

It did not specify the dates of the shutdown.

Leonardo said last month that Boeing's recent production troubles could cost it some 50 million euros ($54 million) in 2024. ($1 = 0.9324 euros) (Writing by Keith Weir, editing by Alvise Armellini)