@article{cheng_zamski_guo_pharr_williamson_2009, title={Salicylic acid stimulates secretion of the normally symplastic enzyme mannitol dehydrogenase: a possible defense against mannitol-secreting fungal pathogens}, volume={230}, ISSN={["1432-2048"]}, DOI={10.1007/s00425-009-1006-3}, abstractNote={The sugar alcohol mannitol is an important carbohydrate with well-documented roles in both metabolism and osmoprotection in many plants and fungi. In addition to these traditionally recognized roles, mannitol is reported to be an antioxidant and as such may play a role in host-pathogen interactions. Current research suggests that pathogenic fungi can secrete mannitol into the apoplast to suppress reactive oxygen-mediated host defenses. Immunoelectron microscopy, immunoblot, and biochemical data reported here show that the normally symplastic plant enzyme, mannitol dehydrogenase (MTD), is secreted into the apoplast after treatment with the endogenous inducer of plant defense responses salicylic acid (SA). In contrast, a cytoplasmic marker protein, hexokinase, remained cytoplasmic after SA-treatment. Secreted MTD retained activity after export to the apoplast. Given that MTD converts mannitol to the sugar mannose, MTD secretion may be an important component of plant defense against mannitol-secreting fungal pathogens such as Alternaria. After SA treatment, MTD was not detected in the Golgi apparatus, and its SA-induced secretion was resistant to brefeldin A, an inhibitor of Golgi-mediated protein transport. Together with the absence of a known extracellular targeting sequence on the MTD protein, these data suggest that a plant's response to pathogen challenge may include secretion of selected defensive proteins by as yet uncharacterized, non-Golgi mechanisms.}, number={6}, journal={PLANTA}, author={Cheng, Fang-yi and Zamski, Eli and Guo, Wei-wen and Pharr, D. Mason and Williamson, John D.}, year={2009}, month={Nov}, pages={1093–1103} } @article{zamski_guo_yamamoto_pharr_williamson_2001, title={Analysis of celery (Apium graveolens) mannitol dehydrogenase (Mtd) promoter regulation in Arabidopsis suggests roles for MTD in key environmental and metabolic responses}, volume={47}, ISSN={["0167-4412"]}, DOI={10.1023/A:1012395121920}, abstractNote={Of the growing list of promising genes for plant improvement, some of the most versatile appear to be those involved in sugar alcohol metabolism. Mannitol, one of the best characterized sugar alcohols, is a significant photosynthetic product in many higher plants. The roles of mannitol as both a metabolite and an osmoprotectant in celery (Apium graveolens) are well documented. However, there is growing evidence that 'metabolites' can also have key roles in other environmental and developmental responses in plants. For instance, in addition to its other properties, mannitol is an antioxidant and may have significant roles in plant-pathogen interactions. The mannitol catabolic enzyme mannitol dehydrogenase (MTD) is a prime modulator of mannitol accumulation in plants. Because the complex regulation of MTD is central to the balanced integration of mannitol metabolism in celery, its study is crucial in clarifying the physiological role(s) of mannitol metabolism in environmental and metabolic responses. In this study we used transformed Arabidopsis to analyze the multiple environmental and metabolic responses of the Mtd promoter. Our data show that all previously described changes in Mtd RNA accumulation in celery cells mirrored changes in Mtd transcription in Arabidopsis. These include up-regulation by salicylic acid, hexokinase-mediated sugar down-regulation, and down-regulation by salt, osmotic stress and ABA. In contrast, the massive up-regulation of Mtd expression in the vascular tissues of salt-stressed Arabidopsis roots suggests a possible role for MTD in mannitol translocation and unloading and its interrelation with sugar metabolism.}, number={5}, journal={PLANT MOLECULAR BIOLOGY}, author={Zamski, E and Guo, WW and Yamamoto, YT and Pharr, DM and Williamson, JD}, year={2001}, pages={621–631} } @article{oh_romanow_smith_zamski_sasse_clouse_1998, title={Soybean BRU1 encodes a functional xyloglucan endotransglycosylase that is highly expressed in inner epicotyl tissues during brassinosteroid-promoted elongation}, volume={39}, ISSN={["1471-9053"]}, DOI={10.1093/oxfordjournals.pcp.a029283}, abstractNote={Brassinosteroids promote soybean epicotyl elongation and regulate expression of BRU1, a gene with homology to xyloglucan endotransglycosylases (XETs). Recombinant BRU1 protein possesses XET activity and in situ hybridization reveals highest BRUl transcript accumulation in inner epicotyl tissue, particularly the phloem and paratracheary parenchyma cells. These results suggest a role for BRUl in vascular development in addition to cell elongation.}, number={1}, journal={PLANT AND CELL PHYSIOLOGY}, author={Oh, MH and Romanow, WG and Smith, RC and Zamski, E and Sasse, J and Clouse, SD}, year={1998}, month={Jan}, pages={124–130} } @article{yamamoto_zamski_williamson_conkling_pharr_1997, title={Subcellular localization of celery mannitol dehydrogenase - A cytosolic metabolic enzyme in nuclei}, volume={115}, ISSN={["0032-0889"]}, DOI={10.1104/pp.115.4.1397}, abstractNote={Abstract}, number={4}, journal={PLANT PHYSIOLOGY}, author={Yamamoto, YT and Zamski, E and Williamson, JD and Conkling, MA and Pharr, DM}, year={1997}, month={Dec}, pages={1397–1403} } @article{zamski_yamamoto_williamson_conkling_pharr_1996, title={Immunolocalization of mannitol dehydrogenase in celery plants and cells}, volume={112}, ISSN={["0032-0889"]}, DOI={10.1104/pp.112.3.931}, abstractNote={Abstract}, number={3}, journal={PLANT PHYSIOLOGY}, author={Zamski, E and Yamamoto, YT and Williamson, JD and Conkling, MA and Pharr, DM}, year={1996}, month={Nov}, pages={931–938} }