The Stress-Induced Soybean NAC Transcription Factor GmNAC81 Plays a Positive Role in Developmentally Programmed Leaf Senescence

Maiana Reis Pimenta, Priscila Alves Silva, Giselle Camargo Mendes, Janaína Roberta Alves, Hanna Durso Neves Caetano, Joao Paulo Batista Machado, Otavio José Bernardes Brustolini, Paola Avelar Carpinetti, Bruno Paes Melo, José Cleydson Ferreira Silva, Gustavo Leão Rosado, Márcia Flores Silva Ferreira (+5 others)
2016 Plant and Cell Physiology  
The onset of leaf senescence is a highly regulated developmental change that is controlled by both genetics and the environment. Senescence is triggered by massive transcriptional reprogramming, but functional information about its underlying regulatory mechanisms is limited. In the current investigation, we performed a functional analysis of the soybean (Glycine max) osmotic stress-and endoplasmic reticulum (ER) stress-induced NAC transcription factor GmNAC81 during natural leaf senescence
more » ... g overexpression studies and reverse genetics. GmNAC81-overexpressing lines displayed accelerated flowering and leaf senescence but otherwise developed normally. The precocious leaf senescence of GmNAC81-overexpressing lines was associated with greater Chl loss, faster photosynthetic decay and higher expression of hydrolytic enzyme-encoding GmNAC81 target genes, including the vacuolar processing enzyme (VPE), an executioner of vacuole-triggered programmed cell death (PCD). Conversely, virus-induced gene silencing-mediated silencing of GmNAC81 delayed leaf senescence and was associated with reductions in Chl loss, lipid peroxidation and the expression of GmNAC81 direct targets. Promoter-reporter studies revealed that the expression pattern of GmNAC81 was associated with senescence in soybean leaves. Our data indicate that GmNAC81 is a positive regulator of age-dependent senescence and may integrate osmotic stress-and ER stressinduced PCD responses with natural leaf senescence through the GmNAC81/VPE regulatory circuit.
doi:10.1093/pcp/pcw059 pmid:27016095 fatcat:6zkmhhnigjhxxiqpv32ajnntyy