JAGGER, an AGP essential for persistent synergid degeneration and polytubey block in Arabidopsis

A precise control of sperm cells delivery and fusion to the egg cell and the central cell is fundamental for the accomplishment of successful double fertilization in flowering plants. This is mostly regulated by female gametophyte egg and central cells, which control the timing of synergids cell degeneration. We recently identified an arabinogalactan protein, AGP4, named JAGGER, that impairs the persistent synergid degeneration, and consequently leads to the attraction of more than one pollen tube into one embryo sac, a situation termed polytubey. jagger mutants revealed an increased rate of polytubey and persistent synergids that do not degenerate. This persistent synergid, is, as we suggested, the cell responsible for attracting an extra pollen tube into the embryo sacs.