Drought Stress in Black Pepper (Piper nigrum): Insights from Marker Studies

Black pepper (Piper nigrum L.) holds significant importance as a spice crop due to its widespread culinary use, economic value, medicinal properties, and historical significance. However, its susceptibility to drought stress significantly challenges sustainable production. Recent molecular markers reveal black pepper's genetic basis for drought tolerance, providing insights that could enhance cultivation strategies and crop resilience. Various marker systems, including Simple Sequence Repeats (SSRs) and Single Nucleotide Polymorphisms (SNPs), have been employed to identify drought-responsive loci. Gene expression studies have highlighted the role of key drought-responsive genes such as dehydrins, osmotin, aquaporins, and transcription factors, which contribute to osmotic adjustment and stress signalling. Next-generation sequencing (NGS) and transcriptome profiling have also facilitated genome-wide identification of polymorphic markers and differentially expressed genes, enabling marker-assisted selection (MAS) for drought tolerance. Despite these advances, field-based validation of candidate genes and functional genomics approaches remains critical for developing drought-resilient black pepper varieties. This review synthesises current research on the molecular basis of drought stress in black pepper and highlights future directions for breeding programs to enhance drought tolerance.