Alison Watkins has quit as chief executive of GrainCorp after the rejection of the grain handler's takeover by Archer Daniels Midland, saying it was "in the best interests" of the company.
Ms Watkins has, after three years as the GrainCorp boss, revealed her "intention to resign to pursue another opportunity in the corporate sector", the Sydney-based group said.
She has been appointed managing director of Coca-Cola Amatil, the Australian beverages group.
News of her departure, to take place at the end of January, follows Friday's decision by Joe Hockey, the Australian treasurer, to block the grain handler's Aus$3.4bn ($3.1bn) takeover by US-based agribusiness giant Archer Daniels Midland on grounds that the "contentious" deal "would not be in our national interest".
Ms Watkins, who said that she had "carefully weighed [her] options" since the deal's rejection, added that she had intended anyway to quit the company after the takeover was completed.
But after Mr Hockey's "unexpected" decision, "I feel it is in the best interests of GrainCorp, our people and customers that I move on now and allow the board to find new leadership to take the business forward into its new phase", she said.
Don Taylor, the GrainCorp chief executive, said that it had accepted Ms Watkins' resignation with "great regret".
However, he acknowledged that "the expectation in the investment community was that ADM's offer for GrainCorp would be approved and effected in the near term.
"In that context, it is not surprising that an executive of Alison's calibre has attracted interest and had new opportunities presented to her."
Mr Taylor added that Ms Watkins would leave a "lasting legacy" at GrainCorp, which she joined in July 2010 from fund manager Bennelong Group.
Her CV also includes a spell as partner at consultancy McKinsey, and on the board of Australia's Woolworths, and Ms Watkins, who grew up on a farm in Tasmania, remains a non-executive director at Australia & New Zealand Bank, although she is to give up this post in April.
She joined GrainCorp after a four-month interregnum, following the surprise departure of Mark Irwin as chief executive.
During her reign, GrainCorp solidified its place as a world player in the malt market, which it gained with the 2009 acquisition of United Malt Holdings, and expanded its reach into areas such as Asia to improve its foothold in growing markets for Australian crops.
Mr Taylor will take over as acting chief executive after Mr Watkins' departure.
GrainCorp shares closed down 3.6% at Aus$8.41 in Sydney, their lowest finish since March last year.