AUTHOR=Lezzhov Alexander A. , Morozov Sergey Y. , Solovyev Andrey G. TITLE=Phloem Exit as a Possible Control Point in Selective Systemic Transport of RNA JOURNAL=Frontiers in Plant Science VOLUME=12 YEAR=2021 URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.739369 DOI=10.3389/fpls.2021.739369 ISSN=1664-462X