A proteomic analysis of peanut seed at different stages of underground development to understand the changes of seed proteins.

Haifen Li,Xuanqiang Liang,Hong Wu,Shaoxiong Li,Xiaoping Chen,Qing Lu,Baojin Zhou,Hao Liu,Haiyan Liu,Ruo Zhou,Yanbin Hong,Mukesh Jain

doi:10.1371/journal.pone.0243132

Haifen Li, Xuanqiang Liang + Show 10 more

Open Access

https://doi.org/10.1371/journal.pone.0243132

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Abstract

In order to obtain more valuable insights into the protein dynamics and accumulation of allergens in seeds during underground development, we performed a proteomic study on developing peanut seeds at seven different stages. A total of 264 proteins with altered abundance and contained at least one unique peptide was detected by matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS). All identified proteins were classified into five functional categories as level 1 and 20 secondary functional categories as level 2. Among them, 88 identified proteins (IPs) were related to carbohydrate/ amino acid/ lipid transport and metabolism, indicating that carbohydrate/amino acid/ lipid metabolism played a key role in the underground development of peanut seeds. Hierarchical cluster analysis showed that all IPs could be classified into eight cluster groups according to the abundance profiles, suggesting that the modulatory patterns of these identified proteins were complicated during seed development. The largest group contained 41 IPs, the expression of which decreased at R 2 and reached a maximum at R3 but gradually decreased from R4. A total of 14 IPs were identified as allergen-like proteins by BLAST with A genome (Arachis duranensis) or B genome (Arachis ipaensis) translated allergen sequences. Abundance profile analysis of 14 identified allergens showed that the expression of all allergen proteins was low or undetectable by 2-DE at the early stages (R1 to R4), and began to accumulate from the R5 stage and gradually increased. Network analysis showed that most of the significant proteins were involved in active metabolic pathways in early development. Real time RT-PCR analysis revealed that transcriptional regulation was approximately consistent with expression at the protein level for 8 selected identified proteins. In addition, some amino acid sequences that may be associated with new allergens were also discussed.

Highlights

As an important oilseed crop worldwide, peanut (Arachis hypogaea L.) is rich in proteins and fats, and it plays a crucial role in the oilseed economy of many countries [1]
Many proteins were classified into the category of metabolic process. These metabolism-related proteins were further categorized into carbohydrate transport and metabolism, amino acid transport and metabolism, inorganic ion transport and metabolism, lipid transport and metabolism, nucleotide transport and metabolism, and coenzyme transport and metabolism
Carbohydrate, amino acid and lipid metabolism accounted for 70.9%

Summary

Introduction

As an important oilseed crop worldwide, peanut (Arachis hypogaea L.) is rich in proteins and fats, and it plays a crucial role in the oilseed economy of many countries [1]. The formation of peanut seeds can be divided into three stages, including morphogenesis, seed filling and seed desiccation [2, 3]. Peanut flowers are produced aerially, and gynophores form after fertilization. The peanut gynophores carrying fertilized ovules grow downward until they penetrate the soil. After penetrating into the soil, the gynophore stems stop elongating, and the fruits in its tips begin to swell and mature horizontally [4, 5]

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