Artigo
The stress-induced soybean NAC transcription factor GmNAC81 plays a positive role in developmentally programmed leaf senescence
Autor
Pimenta, Maiana Reis
Silva, Priscila Alves
Mendes, Giselle Camargo
Alves, Janaına Roberta
Caetano, Hanna Durso Neves
Machado, Joao Paulo Batista
Brustolini, Otavio Jose Bernardes
Carpinetti, Paola Avelar
Melo, Bruno Paes
Silva, Jose Cleydson Ferreira
Rosado, Gustavo Leao
Ferreira, Marcia Flores Silva
Dal-Bianco, Maximillir
Picoli, Edgard Augusto de Toledo
Aragao, Francisco Jose Lima
Ramos, Humberto Josue Oliveira
Fontes, Elizabeth Pacheco Batista
Institución
Resumen
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 using 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 stress-induced PCD responses with natural leaf senescence through the GmNAC81/VPE regulatory circuit.