Abstract
Among 18 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase homologous genes existing in the banana genome there are two genes, Mh-ACO1 and Mh-ACO2, that participate in banana fruit ripening. To better understand the physiological functions of Mh-ACO1 and Mh-ACO2, two hairpin-type siRNA expression vectors targeting both the Mh-ACO1 and Mh-ACO2 were constructed and incorporated into the banana genome by Agrobacterium-mediated transformation. The generation of Mh-ACO1 and Mh-ACO2 RNAi transgenic banana plants was confirmed by Southern blot analysis. To gain insights into the functional diversity and complexity between Mh-ACO1 and Mh-ACO2, transcriptome sequencing of banana fruits using the Illumina next-generation sequencer was performed. A total of 32,093,976 reads, assembled into 88,031 unigenes for 123,617 transcripts were obtained. Significantly enriched Gene Oncology (GO) terms and the number of differentially expressed genes (DEGs) with GO annotation were ‘catalytic activity’ (1327, 56.4%), ‘heme binding’ (65, 2.76%), ‘tetrapyrrole binding’ (66, 2.81%), and ‘oxidoreductase activity’ (287, 12.21%). Real-time RT-PCR was further performed with mRNAs from both peel and pulp of banana fruits in Mh-ACO1 and Mh-ACO2 RNAi transgenic plants. The results showed that expression levels of genes related to ethylene signaling in ripening banana fruits were strongly influenced by the expression of genes associated with ethylene biosynthesis.
Highlights
Banana is a typical climacteric fruit of high economic importance that originated in Southeast Asia [1,2]
Ethylene biosynthesis begins from S-adenosylmethionine (SAM); SAM is synthesized from methionine and ATP, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) and ACC oxidase (ACO) catalyze the two key steps of the ethylene biosynthesis pathway [6,7]
ACC oxidase plays a key role in ethylene biosynthesis for the conversion of ACC to ethylene [8]
Summary
Banana is a typical climacteric fruit of high economic importance that originated in Southeast Asia [1,2]. The rate-limiting step catalyzed by ACS involves the cyclization of SAM to ACC, and 5 -methylthioadenosine (MTA) is produced by ACS to utilize the synthesis of new methionine by the activated methyl cycle. This salvage pathway preserves the methyl group for another round of ethylene production. ACC synthase, or genomic sequences, were isolated from numerous climacteric fruits such as apple [11], papaya [12], kiwifruit [13], sugarcane [14], peach [15], banana [16], tomato [17], and pear [18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
