IDENTIFICATION OF MA-ACS GENE FAMILY AND EXPRESSION STUDY OF MA-ACS1 GENE IN Musa acuminata (AAA GROUP) kultivar PISANG AMBON LUMUT FRUIT BASED ON REAL TIME PCR (qPCR)

• Main Author: UTAMI KARMAWAN, LISTYA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/34693
• Institution: Institut Teknologi Bandung

Musa acuminata (AAA group) kultivar pisang ambon lumut is a native fruit from Indonesia which would become a promising export commodity. Banana is one of climacteric fruit, which ripens in a relative short time. Molecular strategy for regulating pisang ambon ripening is being developed using silencing technology to knock down ACC synthase (ACS) gene expression. ACS gene is a multigene family, which encode ACC synthase isozymes involved in ethylene biosynthesis. Data concerning the characterization of ACS gene family in pisang ambon lumut is still limited. PCR analysis was done using nine pairs of specific primers to confirm the existence of ACS gene family in pisang ambon lumut. Nine PCR fragments of ACS gene family were found and called as MA-ACS1-9. Qualitative expression analysis for MA-ACS1 and MA-ACS2 isolated from pulp shows that only MA-ACS1 was expressed during pisang ambon lumut ripening. MA-ACS1 genomic and cDNA fragments were isolated from pulp using a pair of primers ACS1F and R. Genomic fragment of MA-ACS1 shows highest homology with MACS1 gene from Musa acuminata kultivar Hsian Jien Chiao (GenBank accession number AF056164). MA-ACS1 genomic fragment had three introns, four exons, and one stop codon. Analysis of putative protein showed highest homology with ACC synthase Musa acuminata kultivar Hsian Jien Chiao (GenBank accession number AAQ13437). Seven conserved motives for ACC synthase gene were found in MA-ACS1 putative protein. Furthermore, according to TMHMM (Transmembrane Hidden Markov Model) analysis it was predicted that the putative protein MA-ACS1 did not have transmembrane domain. Moreover, expression analysis using qPCR (quantitative PCR) showed that MA-ACS1 gene expression increased significantly in the third day, reached maximum at the fifth day, and then decreased in the seventh day after harvesting.