As an important food crop and oil crop, soybean (Glycine max) is capable of
nitrogen-fixing by root nodule. Previous studies showed that GmNMH7, a
transcription factor of MADS-box family, is associated with nodule
development. However, its specific function is unknown. Researchers Ma
Wen-ya and Liu Wei from the Chinese Academy of Agricultural Sciences
recently found that GmNMH7 is specifically expressed in root and nodule.



Analysis also found that the expression pattern of GmNMH7 was similar to
several genes involved in the development of nodules after rhizobia
inoculation. The earlier expression peak of GmNMH7 compared to the other
genes indicates that the gene is related to the NF (nod factor) signaling
pathway and functions in the early development of nodule.



Overexpression of GmNMH7 in hairy roots significantly reduced the nodule
number and the root length. Moreover, the overexpression of GmNMH7 reduced
the content of abscissic acid, and increased the content of gibberellins in
the transgenic hairy roots.



This study concludes that GmNMH7 participates in the NF signaling pathway
and negatively regulates nodulation probably through regulating the content
of gibberellins.



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