Petal senescence is a complex process regulated by intricate hormonal signaling and transcriptional networks. Although NAC transcription factors are well-known regulators of plant senescence, their roles in Paeonia lactiflora petal senescence remain largely unexplored. Here, we identified 46 members of the NAC family from P. lactiflora ‘Duchesse de Nemours’ flowers. PlNAC72 was functionally characterized as a central positive regulator of petal senescence. Silencing PlNAC72 delayed senescence in P. lactiflora petals, while its overexpression in Arabidopsis triggered premature leaf senescence. PlNAC72 also promoted the expression of senescence-related genes involved in ethylene and abscisic acid biosynthesis as well as organ senescence, and interacted with the promoters of PlSGR1 , PlCYP707A4 , PlPAD4 , PlNCED3 and PlDXS . Overexpression of PlNAC72 in Arabidopsis thaliana increased the accumulation of abscisic acid, 1-aminocyclopropanecarboxylic acid, salicylic acid and jasmonic acid-isoleucine, while suppressing gibberellic acid biosynthesis, thereby accelerating petal senescence. These results demonstrate that PlNAC72 regulates hormone biosynthetic pathways to promote petal senescence in P. lactiflora petals. This study provides a molecular framework for manipulating floral longevity in ornamental plants and offers a theoretical basis for genetic strategies aimed at extending the vase life of P. lactiflora as a cut flower commodity.
Sun et al. (Thu,) studied this question.