Effect of Nitric Oxide on Ethylene Synthesis and Softening of Banana Fruit Slice during Ripening

Abstract

The effects of nitric oxide (NO) on ethylene synthesis and softening of ripening-initiated banana slice were investigated. Fruit firmness, color, and contents of starch and acid-soluble pectin (ASP) were measured. In addition, ethylene production, 1-aminocyclopropane-1-carboxylic acid (ACC) content, expression and activities of ACC synthase (ACS) and ACC oxidase (ACO), and activities of cell-wall-modifying enzymes, polygalacturonase (PG), pectin methylesterase (PME), and endo-beta-1,4-glucanase, were analyzed. Application of NO reduced ethylene production, inhibited degreening of the peel and delayed softening of the pulp. The decrease of ethylene production was associated with the reduction in the activity of ACO and the expression of the MA-ACO1 gene. Moreover, the NO-treated fruit showed a lower expression of the MA-ACS1 gene but higher ACS activity and ACC content. In addition, NO treatment decreased the activities of PG, PME, and endo-beta-1,4-glucanase and maintained higher contents of ASP and starch, which may account for the delay of softening. We proposed that the inhibition of ACO activity and transcription of gene MA-ACO1 by NO resulted in decreased ethylene synthesis and the delay of ripening of banana slice.

Nitric oxide counters ethylene effects on ripening fruits

“…27 NO treatment also improved the shelf life and desirable attributes of banana, 28 tomato 29 and Kiwifruit 30,31 and in some climacteric and non-climacteric fruits ( Table 1).…”

“…NO delayed the expression of homologs of ACO but not ACS in tomatos 44 and bananas. 28 Transcript accumulation of the ethylene biosynthesis gene ACS2 in tobacco could be related to the concentration of applied NO 45 suggesting that NO effect is mainly on ACO rather than ACS. Another important aspect of NO's mode of ethylene regulation is through the regulation of the effect of hydrogen peroxide, the latter being an effective inducer of ethylene biosynthetic gene transcription.…”

Nitric Oxide Fumigation Delays Mango Fruit Ripening

“…NO has been reported to bind with ACO and 1-aminocyclopropane-1-carboxylic acid (ACC) to form a stable ternary complex (Tierney et al, 2005). It may also be argued that possibly NO may have reduced the activity of ACO and down regulated the expression MA-ACO1 gene, with higher ACS activity and ACC content accumulation as reported in banana (Cheng et al, 2009). It is surmised that either one of these proposed or any other mechanism of action of NO in reducing ethylene production may be operating in 'Kensington Pride′ mango fruit.…”

“…Short storage life limits its export to distant markets. Postharvest exogenous application of nitric oxide (NO) has been reported to delay ripening of climacteric fruits such as banana, tomato and plum (Cheng et al, 2009;Eum et al, 2009;Singh et al, 2009). No research work has been reported on the role of NO fumigation in modulating mango fruit ripening.…”

Eliciting Plant Defense on Anthracnose Disease in Chili (Capsicum annuum Linn.) by Sodium Nitroprusside Solution

“…NO not only regulate plant resistance through direct regulation of defense enzymes and related genes [7,25]. NO fumigation also inhibited ethylene biosynthesis in resulting suppressed the content of 1-aminocyclopropane-1-caboxylic acid (ACC) and the activity of ACC synthase (ACS) in banana [6], mangoes [32] and oranges [14].…”