Functional validation of Capsicum frutescens aminotransferase gene involved in vanillylamine biosynthesis using Agrobacterium mediated genetic transformation studies in Nicotiana tabacum and Capsicum frutescens calli cultures.

Capsaicinoid biosynthesis involves the participation of two substrates viz. vanillylamine and C9–C11 fatty
acid moieties. Vanillylamine which is a derivative of vanillin is synthesized through a transaminase reaction
in the phenylpropanoid pathway of capsaicinoid synthesis. Here we report the functional validation
of earlier reported putative aminotransferase gene for vanillylamine biosynthesis in heterologous system
using Agrobacterium mediated genetic transformation studies in Nicotiana tabacum and Capsicum
frutescens calli cultures. Molecular analysis tools comprising PCR and Southern blot analysis have shown
the integration of the foreign gene in N. tabacum and C. frutescens calli cultures. The study shows the
production of vanillylamine in transformed N. tabacum callus cultures and also the reduction of vanillylamine
production when whole gene based antisense binary vector construct was used in transformation
of C. frutescens callus cultures. Vanillylamine production, aminotransferase assay with Western blot analysis
for crude proteins of transformants established the production of putative aminotransferase (pAMT)
protein in alternate plant. The result is a clear evidence of involvement of the reported putative aminotransferase
responsible for vanillylamine biosynthesis in capsaicinoid biosynthesis pathway, confirming
the gene function through functional validation.