Abstract Detail

Anatomy and Morphology

Sun, Qiang [1], Boudreau, Bailey [2].

Early Developmental Events of Vascular Occlusion in Grapevines Infected with Pierce’s Disease.

Pierce’s disease (PD) symptom progression of grapevines is mostly due to a decline in water conduction in sick vines caused by vascular occlusion. Tylose is a predominant structure of the vascular occlusion and extensively occurs in the vessel system of vines with severe PD symptoms. Tylose is an outgrowth of a parenchyma cell into the lumen of its adjacent vessel. Details about the early development of tylose are still unclear. Our recent study has focused on tylose development from a vessel-parenchyma pit membrane (V-P PM), a parenchyma cell and multiple adjacent parenchyma cells. Our results have indicated that V-P PM experienced a modification before tylose initiation. The modification occurred more or less uniformly over the PM in a small V-P pit but not uniformly in a large transversely elongated pit that had multiple modified regions over the PM. Modification appeared first as a relatively rough PM surface with secretion and proceeded with a small bump from the rough surface area.  A single tylose emerged from the modified PM in a small pit, while 2-5 tyloses were initiated from the single PM in a large V-P pit with 2 tyloses being the most common occurrence pattern. Tylose at this early stage was usually spherical and was covered with amorphous substances. In the pits with multiple tyloses, either all tyloses enlarged but only to a limited extent, or one enlarged with a size significantly larger than the other(s). Tyloses may initiate in a relatively simultaneous way from multiple V-P pits of a same parenchyma cell. Similarly, one tylose usually developed into a significantly large structure with others remaining small, although multiple tyloses may also expand to some extents in some cases. Coordination in tylose initiation and expansion was common among adjacent parenchyma cells and resulted in similar sizes of fully developed adjacent tyloses. However, pace of tylose development from different adjacent parenchyma cells may differ significantly with some tyloses being much larger with globular or tubular structures. After reachng its final size, a tylose accumulated secondary cell wall and developed blind pits and/or pit pairs with adjacent tyloses that were derived even from a same parenchyma cell.  This information certainly helps to better understand the tylose formation mechanism and is also essential to explore any effective approaches in control of tylose development in grapevines with PD and other plants with vascular diseases.

Related Links:

1 - University Of Wisconsin-Stevens Point, Department Of Biology, 348 Chemistry Biology Building, 2101 Fourth Avenue, Stevens Point, WI, 54481, United States
2 - University of Wisconsin-Stevens Point, Department of Biology, 800 Reserve Street, Stevens Point, WI, 54481, USA

Vascular occlusion
Pit membrane
Cell wall structure

Presentation Type: Poster This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PAM004
Abstract ID:413
Candidate for Awards:None

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