* FTSEurofirst 300 closes up 4.2 pct
* Best one-day gain since 2011 after sell-off
* Syngenta surges on sign of sweetened Monsanto offer
* Goldman Sachs strategists cut equities position (Updates with closing prices)
By Sudip Kar-Gupta
LONDON, Aug 25 (Reuters) - European shares rose more than 4 percent on Tuesday, their best one-day gain since late 2011, as a rate cut in China fuelled a recovery from a bruising 48-hour sell-off.
Battered mining and technology stocks were among the big winners when China moved to support its stuttering economy and a plunging stock market that had sent shockwaves around the globe.
China's woes have led to fears of fresh deflationary pressures around the world. The European Central Bank is ready to take further measures if the inflation outlook changes materially, ECB Vice President Vitor Constancio said.
"We think the corner in markets has been turned," Bank of America-Merrill Lynch strategists wrote in a note to clients. "We would acknowledge, though, that this sell-off has done some serious damage to markets and any recovery is likely to take time and be volatile."
The pan-European FTSEurofirst 300 index, which slumped 5.4 percent on Monday, closed up 4.2 percent. The blue-chip Euro STOXX 50 index rose 4.7 percent.
German chipmaker Infineon rose 10 percent while miner Antofagasta gained 8.7 percent.
Swiss agricultural chemicals company Syngenta was up 5.9 percent after a source said that Monsanto had sweetened a takeover offer.
World financial markets have been rattled by a sell-off in the Chinese stock market after the devaluation of the yuan this month.
Some investors took heart from a rise in the German IFO business climate index for August and said that domestic demand across Europe was showing broadly positive signs.
"There are solid reasons to be worried about the global growth outlook, given emerging markets and systemic fears in China," said Valentijn van Nieuwenhuijzen, head of multi-asset strategy at NN Investment Partners. "However, it is a risk - not yet a reality - that this will spread to the developed world. The IFO number this morning ... shows domestic demand is holding up quite well so far."
Goldman Sachs' strategists cut their position on equities to 'neutral' from 'overweight' because of the drop in China, though they did not expect the sell-off to cause a global recession, citing signs of economic growth in the United States and Europe.
"In the meantime, we recognise the shift in sentiment that is being reflected in recent price action both in equities and, via falling inflation expectations, in bonds," they wrote in a note. ($1 = 0.8642 euros)
Europe bourses in 2015: link.reuters.com/pap87v
Asset performance in 2015: link.reuters.com/gap87v
Today's European research round-up (Editing by Larry King)