Whole genome based identification of BAHD acyltransferase gene involved in piperine biosynthetic pathway in black pepper.

Black pepper (Piper nigrum L.), a crop of the genus Piper, is an important spice that has both economic and ecological significance. It is widely regarded as the "King of Spices" because of its pungency, attributed to the presence of piperine. BAHD acyl transferase, the crucial enzyme involved in the final step in piperine biosynthesis was the focus of our study and the aim was to identify the candidate isoform involved in biosynthesis of piperine. Reference genome-based analysis of black pepper identified six BAHD-AT isoforms and mapping of these sequences revealed that the isoforms were situated on six distinct chromosomes. By using specific primers for each of these transcripts, qPCR analysis was done in different tissues as well as berry stages to obtain detectable amplification products. Expression profiles of isoforms from chromosome 6 correlated well with piperine content compared to other five isoforms, across tissues and was therefore assumed to be involved in biosynthesis of piperine. In addition to this, we could also identify the binding sites of MYB transcription factor in the cis-regulatory regions of the isoforms. We also used in-silico docking and molecular dynamics simulation to calculate the binding free energy of the ligand and confirmed that among all the isoforms, BAHD-AT from chromosome 6 had the lowest free binding energy and highest affinity towards the ligand. Our findings are expected to aid the identification of new genes connecting enzymes involved in the biosynthetic pathway of piperine, which will have major implications for future research in metabolic engineering.Communicated by Ramaswamy H. Sarma.

Dataset of De Novo hybrid berry transcriptome profiling and characterization of Piper species (Piper nigrum and Piper longum) using Illumina and Nanopore sequencing.

Piper nigrum and Piper longum are the most popular and economically essential spice crops globally valued for their aromatic alkaloids, especially Piperine. However, Piperine synthesis pathway mechanisms are not yet well known. This work was aimed to generate the full-length comparative berry transcriptome analysis dataset of P. nigrum and P. longum by Illumina and Nanopore sequencing platforms. While short-read sequencing technology is widely using to capture transcriptome profiles, there are still some limitations due to the read length. We used Oxford Nanopore technology for long reads and the Illumina sequencing platform for short reads to generate a hybrid transcriptome assembly from half matured and fully matured berries of P. nigrum and P. longum. From P. nigrum and P. longum 37.3 million and 38.1 million raw reads were generated respectively. A total of 308369 contigs from P. nigrum and 267715 contigs from P. longum were obtained and successfully annotated. The transcriptome data revealed gene families involved in piperine and other secondary metabolite biosynthetic pathways. The raw data were uploaded to NCBI database. This dataset shed light on the further exploration of the piperine biosynthetic pathway, its transcriptomic changes, and evolution. Data generated has been submitted to SRA of NCBI with Bio samples accession: (SAMN13981803, SAMN22826456).