German Marcelo A, Dai Nir, Matsevitz Tanya, Hanael Rana, Petreikov Marina, Bernstein Nirit, Ioffe Marina, Shahak Yosepha, Schaffer Arthur A, Granot David
Institute of Field and Garden Crops, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel.
Plant J. 2003 Jun;34(6):837-46. doi: 10.1046/j.1365-313x.2003.01765.x.
Fructokinases catalyze the key step of fructose phosphorylation in plants. LeFRK2, the major fructokinase-encoding gene in tomato plants, is abundantly expressed in roots, stems, and fruits. To analyze the role of LeFRK2 in plant development, we analyzed transgenic tomato plants with sense and antisense expression of StFRK, the potato homolog of LeFRK2. Increased fructokinase activity had no effect. However, plants in which LeFRK2 was specifically suppressed, either via antisense suppression or via co-suppression, exhibited growth inhibition and wilting of young leaves at daytime. Grafting experiments indicated that a stem interstock of antisense plants was sufficient to inhibit growth and cause leaf wilting. Stem secondary xylem exhibited particular suppression of LeFRK2 and the area of active xylem, estimated by eosin uptake, was significantly smaller in antisense stem compared to that of wild-type plants. These results suggest that LeFRK2 might be required for proper development of xylem that affected growth and wilting.
果糖激酶催化植物中果糖磷酸化的关键步骤。LeFRK2是番茄植株中主要的果糖激酶编码基因，在根、茎和果实中大量表达。为了分析LeFRK2在植物发育中的作用，我们分析了具有LeFRK2的马铃薯同源基因StFRK正义和反义表达的转基因番茄植株。果糖激酶活性增加没有影响。然而，通过反义抑制或共抑制特异性抑制LeFRK2的植株在白天表现出生长抑制和幼叶萎蔫。嫁接实验表明，反义植株的茎中间砧足以抑制生长并导致叶片萎蔫。茎次生木质部对LeFRK2有特别的抑制作用，通过伊红摄取估计，反义茎中活跃木质部的面积与野生型植株相比明显更小。这些结果表明，LeFRK2可能是影响生长和萎蔫的木质部正常发育所必需的。
