By Jon Leyne
BBC News, Tehran
As Iran's new chief nuclear negotiator holds talks with the EU envoy Javier Solana, diplomats will be looking closely for any sign of a more hardline direction in Iranian thinking.
Mr Jalili's debut at negotiations will be keenly watched
They will be the first talks since Saeed Jalili took over from Ali Larijani.
The Iranian government has insisted that the surprise resignation of Mr Larijani as chief negotiator will not change policy.
But his replacement is a close ally of President Mahmoud Ahmadinejad. So Mr Jalili's words will be closely scrutinised for any sign of a more uncompromising position.
Mr Larijani was a believer in talking. He is the man who helped to negotiate the release of the British sailors when they were captured by Iran earlier this year.
By contrast, Mr Ahmadinejad told the United Nations last month that on the nuclear issue the "case was closed."
Ali Larijani (left) held frequent talks with the EU's Javier Solana
That is not to say that Iran is likely to break off negotiations any time soon.
At the moment these are only "talks about talks" as the West has refused to enter substantive negotiations unless Iran suspends its programme to enrich uranium.
Western countries fear this could eventually produce a nuclear bomb.
It is in Iran's interest to keep talking as long as possible, even if it does not give any ground, in order to fend off new sanctions, or worse.
Some diplomats in Tehran even interpreted Mr Larijani's replacement as a way to string out the talks.
But the deputy speaker of the Iranian parliament, Mohammad Reza Bahonar, publicly voiced what many had been saying privately.
"It was no longer possible for Mr Larijani to continue with Mr Ahmadinejad," he said, suggesting that the two men fell out on policy, and possibly personalities as well.
Strangely, Mr Larijani will still be in Rome for the talks, as the representative of the Supreme Leader, Ayatollah Ali Khamenei.
And one of the Supreme Leader's top advisers said Mr Larijani should not have been allowed to resign at all.
That is a peculiar comment, as normally in Iran, the Supreme Leader outranks the president, and would surely have been consulted before Mr Larijani was let go.
It is one more sign of deep divisions within the Iranian government about their tactics in the nuclear dispute, but also further evidence that those around Mr Ahmadinejad are consolidating power.