Large-scale analysis of putative soybean regulatory gene expression identifies a Myb gene involved in soybean nodule development.
Nodulation is the result of a symbiosis between legumes and rhizobial bacteria in soil. This symbiosis is mutually beneficial, with the bacteria providing a source of nitrogen to the host while the plant supplies carbon to the symbiont. Nodule development is a complex process that is tightly regulated in the host plant cell through networks of gene expression. In order to examine this regulation in detail, a library of quantitative reverse transcription-polymerase chain reaction primer sets was developed for a large number of soybean (Glycine max) putative regulatory genes available in the current expressed sequence tag collection. This library contained primers specific to soybean transcription factor genes as well as genes involved in chromatin modification and translational regulation. Using this library, we analyzed the expression of this gene set during nodule development. A large number of genes were found to be differentially expressed, especially at the later stages of nodule development when active nitrogen fixation was occurring. Expression of these putative regulatory genes was also analyzed in response to the addition of nitrate as a nitrogen source. This comparative analysis identified genes that may be specifically involved in nitrogen assimilation, metabolism, and the maintenance of active nodules. To address this possibility, the expression of one such candidate was studied in more detail by expressing in soybean roots promoter beta-glucuronidase and green fluorescent protein fusions. This gene, named Control of Nodule Development (CND), encoded a Myb transcription factor gene. When the CND gene was silenced, nodulation was reduced. These results, associated with a strong expression of the CND gene in the vascular tissues, suggest a role for CND in controlling soybean nodulation.
Libault
Marc
M
Division of Plant Sciences, National Center for Soybean Biotechnology, C.S. Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA.
Joshi
Trupti
T
Takahashi
Kaori
K
Hurley-Sommer
Andrea
A
Puricelli
Kari
K
Blake
Sean
S
Finger
Richard E
RE
Taylor
Christopher G
CG
Xu
Dong
D
Nguyen
Henry T
HT
Stacey
Gary
G
D003001:Cloning, Molecular; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D020570:Genes, myb; D009586:Nitrogen Fixation; D010940:Plant Proteins / Q000235:genetics*; D055170:Plant Root Nodulation / Q000235:genetics*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics; D053204:Root Nodules, Plant / Q000235:genetics / Q000254:growth & development; D013025:Glycine max / Q000235:genetics* / Q000254:growth & development; D013559:Symbiosis / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors