Affiliation:
1. National Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, College of Life Science and Technology, Huazhong Agricultural University , Wuhan, Hubei 430070 , China
2. Key Laboratory of Soybean Biology of Chinese Ministry of Education, Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry, Northeast Agricultural University , Harbin, Heilongjiang 150038 , China
Abstract
Abstract
Root nodules are major sources of nitrogen for soybean (Glycine max (L.) Merr.) growth, development, production, and seed quality. Symbiotic nitrogen fixation is time-limited, as the root nodule senesces during the reproductive stage of plant development, specifically during seed development. Nodule senescence is characterized by the induction of senescence-related genes, such as papain-like cysteine proteases (CYPs), which ultimately leads to the degradation of both bacteroids and plant cells. However, how nodule senescence–related genes are activated in soybean is unknown. Here, we identified 2 paralogous NAC transcription factors, GmNAC039 and GmNAC018, as master regulators of nodule senescence. Overexpression of either gene induced soybean nodule senescence with increased cell death as detected using a TUNEL assay, whereas their knockout delayed senescence and increased nitrogenase activity. Transcriptome analysis and nCUT&Tag-qPCR assays revealed that GmNAC039 directly binds to the core motif CAC(A)A and activates the expression of 4 GmCYP genes (GmCYP35, GmCYP37, GmCYP39, and GmCYP45). Similar to GmNAC039 and GmNAC018, overexpression or knockout of GmCYP genes in nodules resulted in precocious or delayed senescence, respectively. These data provide essential insights into the regulatory mechanisms of nodule senescence, in which GmNAC039 and GmNAC018 directly activate the expression of GmCYP genes to promote nodule senescence.
Funder
National Key R&D Program of China
the National Natural Science Foundation of China
the Natural Science Foundation of Hubei Province
BaiChuan and Longyun Programs
College of Life Science and Technology
HZAU
Publisher
Oxford University Press (OUP)
Subject
Cell Biology,Plant Science
Cited by
7 articles.
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