1-aminocyclopropane-1-carboxylate oxidase 2 reduction effects on physical and physiological responses of Eksotika papaya

• Main Authors: Sekeli, Rogayah, Abdullah, Janna Ong, Muda, Pauziah, Namasivayam, Parameswari, Abu Bakar, Umi Kalsom, Sew, Yun Shin
• Format: Article
• Language: English
• Published: Taylor & Francis 2013
• Online Access: http://psasir.upm.edu.my/id/eprint/28057/1/28057.pdf; http://psasir.upm.edu.my/id/eprint/28057/; http://www.tandfonline.com/doi/abs/10.1080/15427528.2013.795205
• Institution: Universiti Putra Malaysia

The Malaysian Eksotika papaya (Carica papaya L.) has poor keeping quality due to its fast ripening attribute, which leads to post-harvest losses. This study is aimed at extending the shelf life of this perishable Eksotika fruit using antisense technology. A total of 6,000 Eksotika somatic embryogenic calli was transformed with the antisense 1-aminocyclopropane-1-carboxylic acid oxidase 2 gene (ACO2) construct, and 46 PCR-positive putative transformants were obtained. Gene expression analysis using real-time PCR on the 46 regenerated putative transgenic lines revealed that 42 showed down-regulation of the ACO2 gene with two- to five-fold differences among the lines. Out of 22 independently selected transformed lines grown under net house conditions, 16 harbored a single copy of the transgene. Physical stature of the transgenic plants was not significantly different from that of the non-transformed seed-derived papaya plants. Physiological evaluations of the transgenic fruits showed a 15-day delay in ripening compared with 4 days of the non-transformed seed-derived papaya fruits. The total soluble solid (TSS) of the transgenic fruits was comparable to that of the non-transformed seed-derived fruits with similar 11-15°Brix, implying the transgenes did not affect the TSS content.