Changes in stomatal function and water use efficiency in potato plants with altered sucrolytic activity

• Published in: Plant, cell and environment cell and environment, 2012-04, Vol.35 (4), p.747-759
• Main Authors: ANTUNES, WERNER C., PROVART, NICHOLAS J., WILLIAMS, THOMAS C. R., LOUREIRO, MARCELO E.
• Format: Article
• Language: English
• Subjects: beta-Fructofuranosidase - genetics; Biological and medical sciences; Carbon Dioxide - metabolism; Fundamental and applied biological sciences. Psychology; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; guard cell; invertase; Photosynthesis - physiology; Plant Leaves - enzymology; Plant Leaves - genetics; Plant Leaves - physiology; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Stomata - physiology; Plant Transpiration - physiology; Plants, Genetically Modified; RNA, Antisense - genetics; RNA, Plant - genetics; Saccharomyces cerevisiae Proteins - genetics; Solanum tuberosum - enzymology; Solanum tuberosum - genetics; Solanum tuberosum - physiology; Sucrose - metabolism; sucrose synthase; Water - physiology
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/j.1365-3040.2011.02448.x

ABSTRACT As water availability for agriculture decreases, breeding or engineering of crops with improved water use efficiency (WUE) will be necessary. As stomata are responsible for controlling gas exchange across the plant epidermis, metabolic processes influencing solute accumulation in guard cells are potential targets for engineering. In addition to its role as an osmoticum, sucrose breakdown may be required for synthesis of other osmotica or generation of the ATP needed for solute uptake. Thus, alterations in partitioning of sucrose between storage and breakdown may affect stomatal function. In agreement with this hypothesis, potato (Solanum tuberosum) plants expressing an antisense construct targeted against sucrose synthase 3 (SuSy3) exhibited decreased stomatal conductance, a slight reduction in CO2 fixation and increased WUE. Conversely, plants with increased guard cell acid invertase activity caused by the introduction of the SUC2 gene from yeast had increased stomatal conductance, increased CO2 fixation and decreased WUE. 14CO2 feeding experiments indicated that these effects cannot be attributed to alterations in photosynthetic capacity, and most likely reflect alterations in stomatal function. These results highlight the important role that sucrose breakdown may play in guard cell function and indicate the feasibility of manipulating plant WUE through engineering of guard cell sucrose metabolism. Since stomata are responsible for controlling gas exchange across the plant epidermis metabolic processes influencing solute accumulation in guard cells are potential targets for engineering for improved water use efficiency. To investigate the role of sucrose in stomatal function transgenic potato plants were created with alterations in guard cell sucrolytic activity. Decreased stomatal conductance and increased water use efficiency was observed in lines with decreased sucrose synthase activity (SuSy3 isoform), whilst increased stomatal conductance occurred in lines expressing the yeast SUC2 gene (acid invertase) specifically in guard cells. These results suggest that sucrose breakdown may be important in the control of stomatal aperture.