Methyl jasmonate treatment promotes flower opening of cut Eustoma by inducing cell wall loosening proteins in petals

Abstract

Establishing the technique for controlling the rate of cut flower opening is important to maintain appropriate cut flower supplies to meet consumer demand. Cut flowers of Eustoma grandiflorum (Raf.) Shinn. were held in a vase solution containing (±)-abscisic acid (ABA), 6-benzylaminopurine (BA), gibberellic acid-3 (GA), methyl jasmonate (MeJA) or 1-naphthaleneacetic acid (NAA) at 100μM. MeJA accelerated flower opening. Only the timing of flowering was earlier, and there was no change in maximum flower diameter at the fully open stage. Expansin and xyloglucan endotransglycosylase/hydrolase (XTH), regarded as cell wall loosing proteins, participate in petal growth from bud stage to the fully open stage in Eustoma. MeJA also accelerated the expression of EgEXPA2, EgEXPA3 and EgXTH1 mRNA and the accumulation of expansin and XTH protein in petals. Meanwhile, the acceleration of both flower opening and expression of these genes was not observed by ABA, BA or GA treatment. It was proposed that early flower opening by JA treatment resulted from petal cell wall loosening by accelerated expression of expansin and XTH.