Department of Plant Sciences, Weizmann Institute of Science, Rehovot, Israel. shira.mintz@weizmann.ac.il|Department of Plant Sciences, Weizmann Institute of Science, Rehovot, Israel. shira.mintz@weizmann.ac.il|Department of Plant Sciences, Weizmann Institute of Science, Rehovot, Israel. shira.mintz@weizmann.ac.il|Department of Plant Sciences, Weizmann Institute of Science, Rehovot, Israel. shira.mintz@weizmann.ac.il