A. Introduction -- Phloem, the integrative avenue / Aart J.E. van Bel and Gary A. Thompson -- Cell biology of sieve element-companion cell complexes / Rosemary G. White -- Fundamentals of phloem transport physiology / John W. Patrick -- B. Functional aspects of structural SE components -- Roles of plasma membrane transporters in phloem functions / Mechthild Tegeder, Yong-Ling Ruan, and John W. Patrick -- Regulation of sucrose carrier activities / Christina Kühn -- Cellular basis of electrical potential waves along the phloem and impact of coincident Ca2+ fluxes / Jens B. Hafke and Aart J.E. van Bel -- Sieve element occlusion / Michael Knoblauch and Daniel Mullendore -- C. Long-distance signaling -- Sieve elements : Puzzling activities deciphered through proteomics studies / Sylvie Dinant and William J. Lucas -- Endogenous RNA constituents of the phloem and their possible roles in long-distance signaling / Julia Kehr and Anja Buhtz -- The effect of long-distance signaling on development / David J. Hannapel -- Plant defense and long-distance signaling in the phloem / Frank Gaupels and A. Corina Vlot -- D. Biotic interactions with the phloem -- Role of phloem metabolites in plant defense / Jillian M. Hagel, Akpevwe Onoyovwi, Edward C. Yeung, and Peter J. Facchini -- Viroids and phloem-limited viruses : Unique molecular probes of phloem biology / Lucy R. Stewart, Biao Ding, and Bryce W. Falk -- Spiroplasmas and phytoplasmas : the phytopathogenic mollicutes of the phloem / Allyson M. MacLean and Saskia A. Hogenhout -- Breaching the sieve element : the role of saliva as the molecular interface between aphids and the phloem / Torsten Will, James C. Carolan, and Thomas L. Wilkinson -- Behavioral and molecular-genetic basis of resistance against phloem feeding insects / Linda Walling and Gary A. Thompson