Thap Maeo bananas: Fast ripening and full ethylene perception at low doses
Graphical abstract
Introduction
Bananas are a key crop for Brazilian fruit production. They are the most consumed fruit in natura, and Brazil is the fourth largest producer and the second largest consumer market on the planet (FAOSTAT, 2016, POF/IBGE, 2008). In addition to banana production for exportation, Brazil produces many banana cultivars that are specifically cultivated in each region of the country (POF/IBGE, 2008).
As a typical climacteric fruit (Burg & Burg, 1965), bananas must be harvested in a pre-climacteric stage and artificially ripened by induction through ethylene treatment in commercial sheds (Marriott & Palmer, 1980). For this reason, the period during which bananas can be transported and sold is known as ‘greenlife’, comprising the number of days between harvest and the initiation of the natural ripening process (Peacock & Blake, 1970). Climacteric fruit ripening is thus characterized by an increase in ethylene autocatalytic production and respiratory rates (Burg and Burg, 1965, Kumar et al., 2014, Marriott and Palmer, 1980). However, different banana cultivars can present different profiles of ethylene production and respiratory rates during postharvest life (Mota et al., 1997, Soares et al., 2011), which indicates that ethylene sensitivity in response to exogenous treatment can vary by cultivar.
During the banana ripening process, a dynamic interplay of plant signaling substances, transcription factors and hormones triggers a highly coordinated sequence of events. These events include color and texture changes in fruit pulp and peel due to both the degradation of starch (Shiga et al., 2011) and the cell wall polysaccharides, likewise the volatile synthesis (Wyllie & Fellman, 2000). The fruit flavor formation throughout ripening results from the fruit sweetening, the degradation of organic acids, and the synthesis of aroma-related volatile compounds (Seymour, 1993).
The regulation of the banana ripening seems to be also associated with a balance between indol-3-acetic acid (IAA) and abscisic acid (ABA) levels, wherein IAA plays a negative role on triggering ripening once its levels decrease concurrently with the activation of metabolic events of ripening (Purgatto, Lajolo, Nascimento, & Cordenunsi, 2002).
Concerning the starch metabolism, it has been shown that IAA and ABA are closely related to starch breakdown in banana fruit (Purgatto et al., 2002). The exogenous application of IAA delays the transcription and activity of β-amylase (Purgatto, Lajolo, Nascimento, & Cordenunsi, 2001), one of the key enzymes related to the starch breakdown in banana fruit (Nascimento et al., 2006). Therefore, IAA plays retarding the conversion of starch into soluble sugars which leads to the fruit sweetening and the softening process together with the cell wall degradation in banana fruit (Lohani et al., 2004, Mota et al., 1997, Shiga et al., 2011).
By contrast, ABA appears to induce the banana ripening process since its application increases respiratory rates in three days in advance compared to untreated fruit (Vendrell, 1985). ABA treatment also stimulates genes involved in cell wall degradation even independently of ethylene action, indicating that this hormone can act directly in some ripening events (Lohani et al., 2004). Moreover, early ripening caused by biotic stress during banana fruit development is associated with higher levels of ABA and lower levels of IAA (Saraiva et al., 2013). Hence, all these results support that IAA and ABA levels are directly involved in at least some events of the ripening process.
The primary challenge to banana crops in Brazil and many other Latin American countries is the fungal disease Black Leaf Streak Disease, or Black Sigatoka, which is caused by the fungus Mycosphaerella fijiensis Morelet (anamorph: Paracercospora fijiensis (Morelet) Deighton). This is a very aggressive foliar disease that causes severe damage and losses (Ploetz, 2006), premature ripening (Castelan, Saraiva, Lange, Cordenunsi, & Chillet, 2012), and fruit metabolic disorder (Saraiva et al., 2013). Black Sigatoka control is predominantly undertaken through aerially spraying fungicide, which represents a substantial portion of production costs (Ploetz, 2006). Thus, the development of a genetic resistance to Black Sigatoka has become a major focus of banana breeding programs (Jahnabi et al., 2015, Ploetz, 2006).
Thap Maeo is a Brazilian banana cultivar derived from Mysore (Creste, Neto, Silva, & Figueira, 2003). It is a tall plant with a high number of tillers at flowering (around four) and a higher number of fruits and hands per bunch than 24 other cultivars (Mattos et al., 2010). Particularly, Thap Maeo is resistant not only to Black Sigatoka, but also to Yellow Sigatoka and Fusarium wilt (Jesus et al., 2009).
However, like its parent cultivar Mysore, Thap Maeo fruits develop a distinct ripening behavior in which ripening events appear to occur quickly (Shiga et al., 2011, Soares et al., 2011). It demands a careful handling (even higher than Cavendish fruit) and can also show finger drop and peel browning as postharvest defects (personal communication with Thap Maeo producer).
Given the potential of the Thap Maeo as a promising cultivar for the Brazilian market and the lack of information and technologies allowing for its commercial expansion, this work aims to establish the physical, biochemical and physiological aspects of Thap Maeo fruit. It aims to define the best ethylene dosage for treatment, taking into account the fruit ethylene sensitivity assessed by the transcripts levels of genes encoding the ethylene receptors and ethylene biosynthesis enzymes, and also to characterize the ripening concerning the volatile compounds in ripe fruit and the IAA and ABA levels.
Section snippets
Materials
Thap Maeo Bananas (Musa acuminata, AAB, cv. Thap Maeo) were harvested at a commercial plantation located in Itapetininga, São Paulo State, Brazil. Samples were collected from an irrigated area of approximately 50,000 m2 (23°32′15.04″S; 47°59′27.53″W) at a latosol soil location and an average temperature of 21 °C throughout the experiment. Organic fertilizations were conducted by the farmer based on compost and manure applications. Necrotic leaf removal was also performed for disease and pest
Fruit characterization
In order to determine a range of physical and physiological parameters of Thap Maeo bananas, ten different sample collections were performed. The diameter of Thap Maeo fruit was found to range from 30.8 to 35.8 mm, weight from 67.2 to 94.3 g, and length from 11 to 13.3 cm (Table 2). Thap Maeo fruit is thus smaller fruit than Nanicão and Prata cultivars – diameter and length from 37.7 and 14.8 cm, respectively. Those are the types usually marketed in Sao Paulo state (Donato et al., 2006).
Harvests
Acknowledgment
We are thankful to Helena Pontes Chiebao for the ethylene receptors primer design and validation, and the technical assistance of Dr. Tania Shiga and Lucia Helena Justino da Silva. We also thank João Luiz Brandão Martins Junior for providing a well-managed banana field for this trial.
This work were supported by FAPESP (grant 2012/07220-3) and FoRC (FAPESP 2013/07914-8).
References (50)
- et al.
Effects of black leaf streak disease and Sigatoka disease on fruit quality and maturation process of bananas produced on subtropical conditions of southern Brazil
Crop Protection
(2012) - et al.
Influence of different banana cultivars on volatile compounds during ripening in cold storage
Food Research International
(2012) - et al.
Changes in ethylene signaling and MADS box gene expression are associated with banana finger drop
Plant Science
(2014) - et al.
Ethylene-induced ripening in banana evokes expression of defense and stress related genes in fruit tissue
Postharvest Biology and Technology
(2007) - et al.
Breath-by-breath analysis of banana aroma by proton transfer reaction mass spectrometry
International Journal of Mass Spectrometry
(2003) - et al.
Alkylphenol retention indices
Journal of Chromatography A
(2006) Ethylene, storage and ripening temperatures affect Dwarf Brazilian banana finger drop
Postharvest Biology and Technology
(1996)- et al.
The onset of starch degradation during banana ripening is concomitant to changes in the content of free and conjugated forms of indole-3-acetic acid
Journal of Plant Physiology
(2002) - et al.
Comparison of aroma compounds in Dwarf Cavendish banana (Musa spp. AAA) grown from open-field and protected cultivation area
Scientia Horticulturae
(2012) Effect of abscisic acid and ethephon on several parameters of ripening in banana fruit tissue
Plant Science
(1985)
Fruit ripening, abscission, and postharvest disorders
The regulation of 1-aminocyclopropane-1-carboxylic acid synthase gene expression during the transition from system-I to system-II ethylene synthesis in tomato
Plant Physiology
Functional characterization of enzymes forming volatile esters from strawberry and banana
Plant Physiology
Methods of enzimatic analysis
Alphabetical listing
Ethylene action and the ripening of fruits
Science
Starch breakdown during banana ripening - Sucrose synthase and sucrose-phosphate synthase
Journal of Agricultural and Food Chemistry
Genetic characterization of banana cultivars (Musa spp.) from Brazil using microsatellite markers
Euphytica
Routine post-harvest screening of banana/plantain hybrids: Criteria and methods
Behavior of banana varieties and hybrids (Musa spp.), in two production cycle in the southwest of Bahia State
Revista Brasileira de Fruticultura
Analysis of ripening-related gene expression in papaya using an Arabidopsis-based microarray
BMC Plant Biol.
Food and Agriculture Organization of United Nations
The search for a law governing the effect of temperature on banana fruit growth
Fruits
Screening of banana cultivars (Musa AAA group) against Sigatoka leaf spot disease and its seasonal incidence
Annual Plant Protection Science
Characterization of recommended banana cultivars using morphological and molecular descriptors
Crop Breeding and Applied Biotechnology
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