Regulatory inversion in NAC networks steers the timing of age-dependent cell death in plants [RNA-Seq]

Aging is a time-dependent biological phenomenon governed by complex networks of regulatory components and their transitions over lifetime. Yet, there have been limited efforts to pin down age-associated networks and map their dynamic characteristics onto aging phenotypes. Here, we built time-course genetic regulatory networks of NAM/ATAF/CUC (NAC) transcription factors during the course of leaf aging in Arabidopsis, using causal regulatory relationships among NACs identified from mutants of 49 aging-associated NACs. These temporal networks revealed a regulatory inversion from activating to repressive regulatory modes at a pre-senescent stage. The inversion was governed by three hub NACs, and their mutants conferred earlier aging with altered expression of reactive oxygen species and salicylic acid response genes. Overexpression of the hub NACs delayed the regulatory inversion, rendering delayed age-dependent cell death. We conclude that the regulatory inversion in NAC networks at a pre-senescent stage directs when age-dependent cell death should proceed in plants. Overall design: We measured mRNA expression level of anac017, anac082 and anac090 knockout mutants and WT (n=3 for each) at 18 days of leaf age

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Kim HJ, Park JH, Kim J, Kim JJ, Hong S, Kim J, Kim JH, Woo HR, Hyeon C, Lim PO, Nam HG, Hwang D