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AtSUC2 (At1g22710) encodes a phloem-localized sucrose (Suc)/H(+) symporter necessary for efficient Suc transport from source tissues to sink tissues in Arabidopsis (Arabidopsis thaliana). AtSUC2 is highly expressed in the collection phloem of mature leaves, and its function in phloem loading is well established. AtSUC2, however, is also expressed strongly(More)
The definition of "minor" veins in leaves is arbitrary and of uncertain biological significance. Generally, the term refers to the smallest vein classes in the leaf, believed to function in phloem loading. We found that a galactinol synthase promoter, cloned from melon (Cucumis melo), directs expression of the gusA gene to the smallest veins of mature(More)
Substantial symplastic continuity appears to exist between companion cells (CCs) and sieve elements of the phloem, which suggests that small solutes within the CC are subject to indiscriminate long-distance transport via the translocation stream. To test this hypothesis, the distributions of exotic and endogenous solutes synthesized in the CCs of minor(More)
Sucrose is the principal product of photosynthesis used for the distribution of assimilated carbon in plants. Transport mechanisms and efficiency influence photosynthetic productivity by relieving product inhibition and contribute to plant vigor by controlling source/sink relationships and biomass partitioning. Sucrose is synthesized in the cytoplasm and(More)
Photoperiod in plants is perceived by leaves and in many species influences the transition to reproductive growth through long-distance signaling. CONSTANS (CO) is implicated as a mediator between photoperiod perception and the transition to flowering in Arabidopsis. To test the role of CO in long-distance signaling, CO was expressed from a promoter(More)
Agricultural productivity is limited by the removal of sap, alterations in source-sink patterns, and viral diseases vectored by aphids, which are phloem-feeding pests. Here we show that TREHALOSE PHOSPHATE SYNTHASE11 (TPS11) gene-dependent trehalose metabolism regulates Arabidopsis thaliana defense against Myzus persicae (Sülzer), commonly known as the(More)
Genetic studies in Arabidopsis established FLOWERING LOCUS T (FT) as a key flower-promoting gene in photoperiodic systems. Grafting experiments established unequivocal one-to-one relations between SINGLE FLOWER TRUSS (SFT), a tomato homolog of FT, and the hypothetical florigen, in all flowering plants. Additional studies of SFT and SELF PRUNING (SP, homolog(More)
The minor-vein phloem of mature leaves is developmentally and physiologically distinct from the phloem in the rest of the vascular system. Phloem loading of transport sugars occurs in the minor veins, and consistent with this, galactinol synthase is expressed in the minor veins of melon (Cucumis melo) as part of the symplastic-loading mechanism that(More)
BACKGROUND Plant architecture and the timing and distribution of reproductive structures are fundamental agronomic traits shaped by patterns of determinate and indeterminate growth. Florigen, encoded by FLOWERING LOCUS T (FT) in Arabidopsis and SINGLE FLOWER TRUSS (SFT) in tomato, acts as a general growth hormone, advancing determinate growth. Domestication(More)