Background: Non-specific lipid transfer proteins (nsLTPs) are known to transfer various lipid molecules between lipid bilayers in plants. In Arachis duranensis, however, little is known about the nsLTPs and their responses to biotic and abiotic stresses.
Results: In this study, we identified 64 nsLTP family members (AdLTPs) in A. duranensis. These AdLTPs were classified into six subfamilies (Types 1, 2, C, D, E, and G) and were randomly distributed along nine chromosomes. The Ks value and Ka/Ks value significantly differed between Type 1 and Type D subfamilies. Among paralogs, eight AdLTPs were under positive selection, indicating that these AdLTPs might have different functions in the evolutionary history of A. duranensis. qRT-PCR results showed that the expression of AdLTPs changed in response to abiotic stresses, including salinity, PEG, low temperature, and ABA. Using RNA-seq data, we also found three AdLTPs (AdLTP1.14, AdLTPd8, and AdLTPe2) that were possibly associated with resistance to nematode infection. Among them, AdLTP1.14, which belongs to the Type 1 subfamily, was up-regulated at three time points after nematode infection. Co-expression analysis indicated that DOF and WRI1 transcription factors may regulate the AdLTP response to nematode infection.
Conclusions: We identified AdLTPs in A. duranensis. Based on both RNA-seq and qRT-PCR datasets, we found that AdLTPs are involved in responses to biotic and abiotic stresses. Our results could provide valuable genomic information for the breeding of peanut cultivars that are resistant to biotic and abiotic stresses.