One of the great mysteries in plant biology is how, given the clouds of pollen released by dozens of plant species all at the same time, an individual plant can recognize which particular species' pollen grains will induce fertility and which to reject. We are now one step closer to solving the mystery thanks to research recently published in Science by an international team from the University of Massachusetts Amherst and China's Shandong Agricultural University.
Many flowering plants have evolved what's known as "self-incompatibility," or the inability to mate with itself and close relatives. In this way, a plant can avoid the pitfalls of inbreeding. But what about the pollen from species that are more distantly related, yet within the same family?
UMass Amherst's Alice Cheung, Distinguished Professor of Biochemistry and Molecular Biology at UMass Amherst and one of the paper's senior authors and a key member of the team that used the Brassicaceae family of plants which includes cabbages, broccoli, kale, turnips, the oil crop canola and other common vegetables to study the poorly understood mechanism of "interspecific incompatibility," or ISI, which is what keeps pollen from broccoli from fertilizing kale and producing a hybrid species kale-occoli.
The problem is that breeding between distantly related relatives to generate new species with an improved or a wider range of traits is beneficial to agricultural crops and thus food security.
The molecular workings of ISI unfortunately remain "very much a black box, compared with what we know about self-incompatibility systems and their mechanisms," says Cheung.
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