Open AccessMechanism of internal browning of pineapple: The role of gibberellins catabolism gene (AcGA2ox) and GAs
Author(s) -
Qin Zhang,
Xiuwen Rao,
Lubin Zhang,
Congcong He,
Fang Yang,
Shijiang Zhu
Publication year - 2016
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/srep33344
Subject(s) - gibberellin , abscisic acid , catabolism , polyphenol oxidase , browning , oxidase test , arabidopsis , downregulation and upregulation , chemistry , ectopic expression , biochemistry , botany , microbiology and biotechnology , enzyme , biology , gene , mutant , peroxidase
Internal browning (IB), a physiological disorder (PD) that causes severe losses in harvested pineapple, can be induced by exogenous gibberellins (GAs). Over the years, studies have focused on roles of Gibberellin 2-oxidase (GA2oxs), the major GAs catabolic enzyme in plants, in the regulation of changes in morphology or biomass. However, whether GA2oxs could regulate PD has not been reported. Here, a full-length AcGA2ox cDNA was isolated from pineapple, with the putative protein sharing 23.59% to 72.92% identity with GA2oxs from five other plants. Pineapples stored at 5 °C stayed intact, while those stored at 20 °C showed severe IB. Storage at 5 °C enhanced AcGA2ox expression and decreased levels of a GAs (GA 4 ) ‘compared with storage at 20 °C. However, at 20 °C, exogenous application of abscisic acid (ABA) significantly suppressed IB. ABA simultaneously upregulated AcGA2ox and reduced GA 4 . Ectopic expression of AcGA2ox in Arabidopsis resulted in reduced GA 4 , lower seed germination, and shorter hypocotyls and roots, all of which were restored by exogenous GA 4/7 . Moreover, in pineapple, GA 4/7 upregulated polyphenol oxidase, while storage at 5 °C and ABA downregulated it. These results strongly suggest the involvement of AcGA2ox in regulation of GAs levels and a role of AcGA2ox in regulating IB.