Diversity of Insecticidal PA1b Homologs among Legume Seeds from Middle Eastern Region

Abstract

Legumes play a central role in various food systems, with significant socio-economic and environmental impacts. Their high protein content, composed mainly of globulins and albumins, makes them valuable for human food and animal feed. Among the albumins, is Pea Albumin 1 b (PA1b), a 37 amino acid peptide, extracted from the seeds of the peaPisum sativum. The protein displays the knottin scaffold and exhibits potent insecticidal activity against certain insects including cereal weevils and mosquitoes. This toxicity is attributed to the coexistence of several isoforms in peas. The natural diversity of PA1b-like molecules within the legume species of the Fabaceae family has been studied using various molecular, biochemical, and bioinformatic tools. SeveralA1genes coding for this peptide have been characterized in soybeans, bean, barrel medick and other legume species. The aim of is study is to precisely characterize partial A1 genes in legumes of the Faboideae subfamily from the Middle East region using PCR homology. Specifically, the research focuses on the sequence structure of Pea Albumin 1 b (PA1b) variants and establishes phylogenetic relationships between these sequences and publicly available A1b homologs. The toxic effects of seed flour containing PA1b-like molecules are assessed, demonstrating that the newly characterized PA1b homologs retain structural conservation. The study observes both conservation and diversification among A1b homologs, consistent with the divergence of lineages within the Fabaceae family. The toxic effects associated with putative A1b molecules are found across different species and within the same species from different geographical origins. In particular, novel candidates such asVicia sativaandMedicago minimashow promising insecticidal A1b activity. Further analysis of isoforms from these species, including an examination of their expression in different tissues and organs should be undertaken to facilitate the potential use of A1b molecules in agricultural practice.

Vicia sativa subsp. sativa native to the Middle East comprises Pea Albumin1 b-like homologs: A promising natural biopesticide

“…Since V. sativa subsp. sativa originating from Turkey contained the highest amount of peptide, the molecular weight of the peptide sequence of interest previously amplified using genomic DNA [ 32 ] was confirmed by high resolution mass spectrometry ( Supplementary Fig. S1 ).…”

“…Through our previous molecular PA1b-like characterization from different species of the Faboideae subfamily by PCR approach using degenerate primers [ 32 ], we selected Vicia sativa subsp. sativa as a natural source of which potential toxic PA1b-like molecules are present.…”

“…The genomic nucleotide sequences of partial A1 gene previously amplified using PCR approach from Vicia sativa subsp. sativa originating from Turkey were translated in the six open reading frames using the translate tool ( https://web.expasy.org/translate ) [ 32 ]. The peptide sequences with PA1b motifs were selected.…”

“…It also has a strong cytotoxic effect against cellular Sf9 cells. The genomic DNA sequence of the PA1b homolog from this seed previously characterized [ 32 ], shows sequence identity to AG41, a PA1b homolog from the alfalfa ( Medicago truncatula ) roots displaying high insecticidal activity against weevils [ 33 ]. The resulting structural modeling of the identified sequence also shows that it has the same hydrophobic pole as AG41.…”