GS52 ecto-apyrase plays a critical role during soybean nodulation.
Apyrases are non-energy-coupled nucleotide phosphohydrolases that hydrolyze nucleoside triphosphates and nucleoside diphosphates to nucleoside monophosphates and orthophosphates. GS52, a soybean (Glycine soja) ecto-apyrase, was previously shown to be induced very early in response to inoculation with the symbiotic bacterium Bradyrhizobium japonicum. Overexpression of the GS52 ecto-apyrase in Lotus japonicus increased the level of rhizobial infection and enhanced nodulation. These data suggest a critical role for the GS52 ecto-apyrase during nodulation. To further investigate the role of GS52 during nodulation, we used RNA interference to silence GS52 expression in soybean (Glycine max) roots using Agrobacterium rhizogenes-mediated root transformation. Transcript levels of GS52 were significantly reduced in GS52 silenced roots and these roots exhibited reduced numbers of mature nodules. Development of the nodule primordium and subsequent nodule maturation was significantly suppressed in GS52 silenced roots. Transmission electron micrographs of GS52 silenced root nodules showed that early senescence and infected cortical cells were devoid of symbiosome-containing bacteroids. Application of exogenous adenosine diphosphate to silenced GS52 roots restored nodule development. Restored nodules contained bacteroids, thus indicating that extracellular adenosine diphosphate is important during nodulation. These results clearly suggest that GS52 ecto-apyrase catalytic activity is critical for the early B. japonicum infection process, initiation of nodule primordium development, and subsequent nodule organogenesis in soybean.
Govindarajulu
Manjula
M
Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA.
Kim
Sung-Yong
SY
Libault
Marc
M
Berg
R Howard
RH
Tanaka
Kiwamu
K
Stacey
Gary
G
Taylor
Christopher G
CG
D000244:Adenosine Diphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001081:Apyrase / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000378:metabolism; D018532:Pisum sativum / Q000201:enzymology; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics; D011755:Pyrophosphatases / Q000235:genetics* / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D011198:Solanum tuberosum / Q000201:enzymology; D013025:Glycine max / Q000201:enzymology* / Q000235:genetics*; D014158:Transcription, Genetic
D009711:Nucleotides; D010940:Plant Proteins; D012333:RNA, Messenger; D000244:Adenosine Diphosphate; D011755:Pyrophosphatases; D001081:Apyrase