Identification, characterization, and validation of NBS-encoding genes in grass pea

Area of Science:

• Genomics and Molecular Biology
• Plant Science
• Crop Improvement

Background:

• Grass pea (Lathyrus sativus) is a vital crop for food and fodder, yet its genomic resources for trait improvement remain underexplored.
• Nucleotide-binding site-leucine-rich repeat (NBS-LRR) genes are crucial for plant defense against biotic and abiotic stresses, but are largely uncharacterized in grass pea.
• Identifying NBS-LRR genes can facilitate the development of stress-tolerant grass pea varieties.

Purpose of the Study:

• To identify and characterize the NBS-LRR gene family in grass pea using its recently published genome.
• To investigate the evolutionary relationships, domain structures, and conserved motifs of grass pea NBS-LRR genes.
• To analyze the expression patterns of these genes under salt stress and identify potential candidates for crop improvement.

Main Methods:

• Genome-wide identification of NBS-LRR genes using the grass pea genome and transcriptomic data.
• Phylogenetic analysis, domain prediction (TNL, CNL, TIR, RX-CCLike), and motif discovery.
• Gene enrichment analysis for biological processes and identification of upstream transcription factors.
• RNA-Seq and quantitative PCR (qPCR) analysis of gene expression under salt stress.

Main Results:

• A total of 274 NBS-LRR genes were identified in grass pea, classified into TNL (124) and CNL (150) subclasses.
• Genes exhibited diverse exon numbers (1-7) and contained conserved motifs, including P-loop, Uup, and kinase-GTPase.
• Gene enrichment analysis indicated roles in plant defense, innate immunity, and response to hormones like salicylic acid and ethylene.
• Expression analysis revealed high expression in 85% of genes, with significant upregulation of most genes under salt stress, except for three specific genes (LsNBS-D18, LsNBS-D204, LsNBS-D180).

Conclusions:

• The comprehensive identification and characterization of NBS-LRR genes provide a foundation for understanding grass pea's defense mechanisms.
• The identified genes are involved in crucial biological processes and respond to hormonal signaling, suggesting their importance in stress tolerance.
• Expression patterns under salt stress highlight specific NBS-LRR genes as potential targets for breeding improved, stress-resistant grass pea varieties.
• This study contributes valuable insights into the evolution of NBS-LRR genes in legumes and underscores grass pea's potential for agricultural advancement.