Nonclimacteric ripening characteristics of ‘Jen-Ju Bar’ guava conferred by a defect in the expression of the system-2 ACC synthase gene PgACS1

Postharvest Physiology and Handling of Guava Fruit

“…Climacteric guavas are typified in the ‘Li-Tzy Bar’ (‘LTB’) variety, while non-climacteric guavas, which exhibit ethylene auto-catalysis and short shelf-life, are typified in the ‘Jen-Ju Bar’ (‘JJB’) variety. The non-climacteric cultivar showed good stability at low rates of respiration (19.8–7 mg CO 2 kg −1 h −1 ), while the climacteric one indicated high respiratory rates (171 mg CO 2 kg −1 h −1 at climacteric peak) [ 10 ]. The respiratory rate of guava is significantly lower than other varieties such as papaya and banana (20–30 mg CO 2 kg −1 h −1 ), but significantly higher than that of many varieties (60–80 mg CO 2 kg −1 h −1 and 120–150 mg CO 2 kg −1 h −1 , respectively) when the respiratory peak comes.…”

“…Recent research suggests that system-2 defects in non-climacteric guava cultivars are mainly the result of the silencing of the ethylene biosynthesis gene PgACS1 , which governs the ripening period, and PgACS2 , which controls fruit set. In addition, the functioning of system-2 is also affected by the downregulation of PgACO1 and PgACO2 [ 10 ].…”