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Transcriptome analysis of ripe and unripe fruit tissue of banana identifies major metabolic networks involved in fruit ripening process.

Asif MH, Lakhwani D, Pathak S, Gupta P, Bag SK, Nath P, Trivedi PK - BMC Plant Biol. (2014)

Bottom Line: Many of these are associated with cell wall degradation and synthesis of aromatic volatiles.A large number of differentially expressed genes did not align with any of the databases and might be novel genes in banana.The datasets developed in this study will help in developing strategies to manipulate banana fruit ripening and reduce post harvest losses.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Banana is one of the most important crop plants grown in the tropics and sub-tropics. It is a climacteric fruit and undergoes ethylene dependent ripening. Once ripening is initiated, it proceeds at a fast rate making postharvest life short, which can result in heavy economic losses. During the fruit ripening process a number of physiological and biochemical changes take place and thousands of genes from various metabolic pathways are recruited to produce a ripe and edible fruit. To better understand the underlying mechanism of ripening, we undertook a study to evaluate global changes in the transcriptome of the fruit during the ripening process.

Results: We sequenced the transcriptomes of the unripe and ripe stages of banana (Musa accuminata; Dwarf Cavendish) fruit. The transcriptomes were sequenced using a 454 GSFLX-Titanium platform that resulted in more than 7,00,000 high quality (HQ) reads. The assembly of the reads resulted in 19,410 contigs and 92,823 singletons. A large number of the differentially expressed genes identified were linked to ripening dependent processes including ethylene biosynthesis, perception and signalling, cell wall degradation and production of aromatic volatiles. In the banana fruit transcriptomes, we found transcripts included in 120 pathways described in the KEGG database for rice. The members of the expansin and xyloglucan transglycosylase/hydrolase (XTH) gene families were highly up-regulated during ripening, which suggests that they might play important roles in the softening of the fruit. Several genes involved in the synthesis of aromatic volatiles and members of transcription factor families previously reported to be involved in ripening were also identified.

Conclusions: A large number of differentially regulated genes were identified during banana fruit ripening. Many of these are associated with cell wall degradation and synthesis of aromatic volatiles. A large number of differentially expressed genes did not align with any of the databases and might be novel genes in banana. These genes can be good candidates for future studies to establish their role in banana fruit ripening. The datasets developed in this study will help in developing strategies to manipulate banana fruit ripening and reduce post harvest losses.

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Putative pathway and members of gene families involved in the synthesis of aromatic volatiles in banana during fruit ripening. The color scale (representing log fold change values) is shown. LOX (lipoxygenases), HPL (Hydroperoxide lipase), DBAT (10-deacetylbaccatin III 10-O-acetyltransferase), 1-AGPATA (1-acyl-sn-glycerol-3-phosphate acyltransferase 1), DBTNBT (3-N-debenzoyl-2-deoxytaxol N-benzoyltransferase), COMT (chavicol O-methyltransferase), UFGT(flavonol-3-O-glycoside-7-O-glucosyltransferase 1), TAT ( taxadien-5-alpha-ol O-acetyltransferase).
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Fig2: Putative pathway and members of gene families involved in the synthesis of aromatic volatiles in banana during fruit ripening. The color scale (representing log fold change values) is shown. LOX (lipoxygenases), HPL (Hydroperoxide lipase), DBAT (10-deacetylbaccatin III 10-O-acetyltransferase), 1-AGPATA (1-acyl-sn-glycerol-3-phosphate acyltransferase 1), DBTNBT (3-N-debenzoyl-2-deoxytaxol N-benzoyltransferase), COMT (chavicol O-methyltransferase), UFGT(flavonol-3-O-glycoside-7-O-glucosyltransferase 1), TAT ( taxadien-5-alpha-ol O-acetyltransferase).

Mentions: The aroma of the banana fruit is attributed to the presence of various volatiles like isoamyl alcohol, isoamyl acetate, butyl acetate, elemecine and several others [39]. These volatiles are produced primarily by the phenylpropanoid pathway, fatty acid biosynthesis pathway and isoleucine biosynthesis pathway [40]. Since the major components of the aroma and flavor volatiles are esters, the expression of genes involved in biosynthesis of esters from amino acids, fatty acids and unsaturated fatty acids were analysed here. The genes involved in each step were identified (FigureĀ 2) and differential expression was examined. The conversion of sugars to alcohol is mediated by ADH which is further converted to esters by AATs. At least 10 contigs annotated as ADH genes showed more than 2-fold up-regulation in the ripe fruit as compared to unripe fruit. Similarly, the lipoxygenases genes were also significantly up-regulated in the ripe fruit as compared to unripe fruit. A large number of transferases were up-regulated in the ripe sample, which could be playing a putative role in the production of the aroma volatiles.Figure 2


Transcriptome analysis of ripe and unripe fruit tissue of banana identifies major metabolic networks involved in fruit ripening process.

Asif MH, Lakhwani D, Pathak S, Gupta P, Bag SK, Nath P, Trivedi PK - BMC Plant Biol. (2014)

Putative pathway and members of gene families involved in the synthesis of aromatic volatiles in banana during fruit ripening. The color scale (representing log fold change values) is shown. LOX (lipoxygenases), HPL (Hydroperoxide lipase), DBAT (10-deacetylbaccatin III 10-O-acetyltransferase), 1-AGPATA (1-acyl-sn-glycerol-3-phosphate acyltransferase 1), DBTNBT (3-N-debenzoyl-2-deoxytaxol N-benzoyltransferase), COMT (chavicol O-methyltransferase), UFGT(flavonol-3-O-glycoside-7-O-glucosyltransferase 1), TAT ( taxadien-5-alpha-ol O-acetyltransferase).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4263013&req=5

Fig2: Putative pathway and members of gene families involved in the synthesis of aromatic volatiles in banana during fruit ripening. The color scale (representing log fold change values) is shown. LOX (lipoxygenases), HPL (Hydroperoxide lipase), DBAT (10-deacetylbaccatin III 10-O-acetyltransferase), 1-AGPATA (1-acyl-sn-glycerol-3-phosphate acyltransferase 1), DBTNBT (3-N-debenzoyl-2-deoxytaxol N-benzoyltransferase), COMT (chavicol O-methyltransferase), UFGT(flavonol-3-O-glycoside-7-O-glucosyltransferase 1), TAT ( taxadien-5-alpha-ol O-acetyltransferase).
Mentions: The aroma of the banana fruit is attributed to the presence of various volatiles like isoamyl alcohol, isoamyl acetate, butyl acetate, elemecine and several others [39]. These volatiles are produced primarily by the phenylpropanoid pathway, fatty acid biosynthesis pathway and isoleucine biosynthesis pathway [40]. Since the major components of the aroma and flavor volatiles are esters, the expression of genes involved in biosynthesis of esters from amino acids, fatty acids and unsaturated fatty acids were analysed here. The genes involved in each step were identified (FigureĀ 2) and differential expression was examined. The conversion of sugars to alcohol is mediated by ADH which is further converted to esters by AATs. At least 10 contigs annotated as ADH genes showed more than 2-fold up-regulation in the ripe fruit as compared to unripe fruit. Similarly, the lipoxygenases genes were also significantly up-regulated in the ripe fruit as compared to unripe fruit. A large number of transferases were up-regulated in the ripe sample, which could be playing a putative role in the production of the aroma volatiles.Figure 2

Bottom Line: Many of these are associated with cell wall degradation and synthesis of aromatic volatiles.A large number of differentially expressed genes did not align with any of the databases and might be novel genes in banana.The datasets developed in this study will help in developing strategies to manipulate banana fruit ripening and reduce post harvest losses.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Banana is one of the most important crop plants grown in the tropics and sub-tropics. It is a climacteric fruit and undergoes ethylene dependent ripening. Once ripening is initiated, it proceeds at a fast rate making postharvest life short, which can result in heavy economic losses. During the fruit ripening process a number of physiological and biochemical changes take place and thousands of genes from various metabolic pathways are recruited to produce a ripe and edible fruit. To better understand the underlying mechanism of ripening, we undertook a study to evaluate global changes in the transcriptome of the fruit during the ripening process.

Results: We sequenced the transcriptomes of the unripe and ripe stages of banana (Musa accuminata; Dwarf Cavendish) fruit. The transcriptomes were sequenced using a 454 GSFLX-Titanium platform that resulted in more than 7,00,000 high quality (HQ) reads. The assembly of the reads resulted in 19,410 contigs and 92,823 singletons. A large number of the differentially expressed genes identified were linked to ripening dependent processes including ethylene biosynthesis, perception and signalling, cell wall degradation and production of aromatic volatiles. In the banana fruit transcriptomes, we found transcripts included in 120 pathways described in the KEGG database for rice. The members of the expansin and xyloglucan transglycosylase/hydrolase (XTH) gene families were highly up-regulated during ripening, which suggests that they might play important roles in the softening of the fruit. Several genes involved in the synthesis of aromatic volatiles and members of transcription factor families previously reported to be involved in ripening were also identified.

Conclusions: A large number of differentially regulated genes were identified during banana fruit ripening. Many of these are associated with cell wall degradation and synthesis of aromatic volatiles. A large number of differentially expressed genes did not align with any of the databases and might be novel genes in banana. These genes can be good candidates for future studies to establish their role in banana fruit ripening. The datasets developed in this study will help in developing strategies to manipulate banana fruit ripening and reduce post harvest losses.

Show MeSH
Related in: MedlinePlus