Global Tissue Specific Transcriptome Analysis of Musa spp., cv. Grand Naine (AAA) Across Twelve Different Tissues.

Abstract

Untargeted trait manipulation through molecular breeding in a sterile and polyploid crop such as banana can introduce adverse pleiotropic effects. This limitation can be overcome with a precise targeted approach using tissue-specific promoters to induce the desired gene in specific tissues. As the banana plant is highly susceptible to many biotic and abiotic stresses, its defense traits must be enhanced. To generate resilient bananas that can withstand various stresses, we aimed to identify tissue-specific and differentially expressed genes through an RNA-sequencing approach. Transcriptomic analysis was carried out in 12 different developmental tissues (primary root, secondary root, corm rhizome, tip meristem, leaf sheath pseudostem, leaf blade, leaf midrib, peduncle, unripe fruit peel, unripe fruit pulp, ripe fruit peel and ripe fruit pulp) of Cavendish type banana-cv. Grand Naine (AAA). Results showed that 8098 genes were differentially expressed among the 12 tissues, 146 genes were uniquely expressed in specific tissues, and 48 genes were constitutively expressed in all tissues. Functional annotations exhibited that most of the differentially expressed genes were involved in the oxidation-reduction process (391), followed by transcriptional regulation (185) and phosphorylation (184). Gene-enrichment analysis showed that many differentially expressed genes were involved in defense mechanisms associated with phenylpropanoid (55) and terpenoid (49) pathways. The promoters of identified differentially expressed genes can be studied for transient expression with reporter genes and then in stable transformation studies, thereby avoiding pleiotropic effects in genome-manipulated bananas.