The spread of pests and pathogens that damage plant life could cost global agriculture $US540 billion ($A727 billion) a year, according to a report.
The report, released by the Royal Botanic Gardens (RBG) at Kew in London, said that an increase in international trade and travel had left flora facing rising threats from invasive pests and pathogens, and called for greater biosecurity measures.
"Plants underpin all aspects of life on Earth from the air we breathe right through to our food, our crops, our medicines," said Professor Kathy Willis, RBG Kew's director of science.
"If you take one away, what happens to the rest of that ecosystem - how does it impact?"
Researchers also examined the traits that would determine which plant species would cope in a world feeling the effects of climate change.
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Plants with deeper roots and higher wood density are better able to withstand drought, while thicker leaves and taller grasses can cope with higher temperatures, the report found.
Surprisingly, researchers also found that the traits that are likely to help species thrive appear to be transferable across different environments.
"The interesting fact to emerge is that the suite of 'beneficial' traits are, on the whole, the same the world over and are as true in a temperate forest as in a desert," Prof Willis said in a statement.
The report, which involved 128 scientists in 12 countries, found 1730 new plant species had been discovered in the past year.
Nine new species of the climbing vine Mucuna, used in the treatment of Parkinson's disease, were found and named across South East Asia and South and Central America.
