Comparative Proteomics of Peanut Gynophore Development under Dark and Mechanical Stimulation

Peanut (Arachis hypogaea. L) is an important leguminous
crop and source of proteins and lipids. It has attracted widespread
attention of researchers due to its unique growth habit of geocarpy,
which is regulated by geotropism, negative phototropism, and haptotropism.
However, the protein expression pattern and molecular regulatory mechanism
underlying the physiological processes of peanut remain unknown. In
this study, the peanut gynophores under five treatment conditions
were used for proteomic analysis, including aerial growth of the gynophores,
the gynophores penetrated into the soil, as well as aerial growth
of the gynophores under mechanical stimulation, dark, and mechanical
stimulation combined with dark. The analysis of protein abundances
in peanut gynophores under these conditions were conducted using comparative
proteomic approaches. A total of 27 differentially expressed proteins
were identified and further classified into nine biological functional
groups of stress and defense, carbohydrate and energy metabolism,
metabolism, photosynthesis, cell structure, signaling, transcription,
protein folding and degradation, and function unknown. By searching
gene functions against peanut database, 10 genes with similar annotations
were selected as corresponding changed proteins, and their variation
trends in gynophores under such growth conditions were further verified
using quantitative real-time PCR. Overall, the investigation will
benefit to enrich our understanding of the internal mechanisms of
peanut gynophore development and lay a foundation for breeding and
improving crop varieties and qualities.