BACKGROUND
the peanut , also known as the groundnut, is an important oilseed crop in the tropical and subtropical regions of the world.
it is grown on six continents but mainly in asia, africa and america.
peanuts are cultivated on  <dig>  million hectares worldwide, with a total global production of approximately  <dig>  million tons .
china is the largest producer in the world, accounting for  <dig> %  of the total world production .
peanuts have a desirable fatty acid profile and are rich in vitamins, minerals and bioactive materials, including several known heart-healthy nutrients, such as monounsaturated and polyunsaturated fatty acids, potassium, magnesium, copper niacin, arginine, fibre, α-tocopherol, folates, phytosterols, and flavonoids.
indeed, peanut consumption has been associated with an improvement in the overall quality of the diet and nutrient  <cit> .
in china, almost 60% of the peanuts are used to produce peanut oil  <cit> .
peanut oil, due to its high monounsaturated fat content, is considered healthier than saturated oils and is resistant to rancidity.
monounsaturated fat, much of which is oleic acid, is a healthy type of fat that has been implicated in the health of skin  <cit>  and has been demonstrated to reduce cardiovascular disease risk and/or risk factors in both epidemiological and clinical studies  <cit> .
the development of the peanut seed has been studied intensely to understand the physiological, biochemical, and molecular characteristics that determine the oil quality and their beneficial nutritional contributions.
however, the development of the peanut seed is a complex process involving a cascade of biochemical changes, which involve the transcriptional modulation of many genes, yet little is known about these transcriptional changes and their regulation.
to date, little research in this area has been reported.
bi  <cit>  developed a seed cdna library for the peanut to analyse gene expression levels during seed development, and  <dig>  expressed sequence tags  were sequenced and used for microarray analysis.
recently, the development of next-generation high-throughput dna sequencing technology has provided a novel method for both mapping and quantifying transcriptomes   <cit> .
rna-seq technology has been successfully applied quite ubiquitously to species such as humans, yeast, mice, grape, arabidopsis, rice, soybeans, sesame, and sweetpotato  <cit> .
moreover, rna-seq data are highly reproducible, with few systematic discrepancies among technical replicates  <cit> .
the latest paired-end tag sequencing strategy of rna-seq further improves the dna sequencing efficiency and expands short-read lengths, providing a better depiction of transcriptomes  <cit> .
transcriptomic information is used in a wide range of biological studies and provides fundamental insight into biological processes and applications, such as the levels of gene expression  <cit> , the gene expression profiles during development  <cit>  or after experimental treatments  <cit> , gene discovery  <cit> , ssr mining  <cit> , and snp discovery  <cit> .
however, transcriptomic information is lacking for the peanut plant because this information is difficult to obtain and, to date, there has been little interest in such data.
chen  <cit>  reported that the accumulation of seed oil in peanuts could be divided into three stages based on phenotype, namely, the initial accumulation stage, the fast accumulation stage and the steady accumulation stage.
as we are interested in identifying genes that are expressed in the seed during the fast accumulation period, we carried out a global analysis of the peanut transcriptome during seed development using the illumina rna-seq method.
we also present an overview of the rna-seq data for the peanut as a potential model for future rna-seq analyses and to establish a biotechnological platform for peanut research.
methods
sample preparation and sequencing
three peanut varieties, which greatly differ in oil content but are similar in mature process, were used in this study.
jihua  <dig> , a variety with a high oil content , as determined in a  <dig> field experiment in hebei, china, was bred at the hebei institute of agricultural sciences and is widely grown in northern china.
kaixuan01- <dig> , a germplasm resource with a similar oil content , also determined in the above field experiment in hebei, was provided by the yantai institute of agricultural sciences in the shandong province of china.
te <dig> , a germplasm resource with a low oil content , as determined in china, was also used.
for each variety, rna was isolated from ten immature seeds of five plants, which were harvested at  <dig> weeks after flowering during the  <dig> growing season from a farm in hebei province .
total rna was extracted using a previously described method  <cit> .
the rna quality and quantity were determined using an agilent  <dig> bioanalyzer .
beads coated with oligo were used to isolate poly  mrna after the total rna was collected.
fragmentation buffer  was added to digest the mrna to produce short fragments.
the first strand of cdna was synthesised using random hexamer primers, followed by synthesis of the second strand.
the short fragments were purified with the qiaquick pcr purification kit  for both end repair and the poly  addition reaction.
the purified dna libraries were amplified by pcr for  <dig> cycles.
finally, solexa hiseq™  <dig> was employed to sequence the libraries using pcr amplification .
de novo assembly and analysis of illumina reads
the samples were assembled with soapdenovo  <cit>  separately.
the numbers of paired-end illumina reads of jh <dig>  k <dig>  and t <dig> were  <dig> , <dig>   <dig> , <dig>  and  <dig> , <dig>  respectively.
the reads were first combined to form longer fragments, i.e., contigs.
the reads were then mapped back to the contigs, and the paired-end reads and contigs from the same transcript were assembled to form a longer sequence, with n for unknown sequences .
paired-end reads were again used for gap filling of the scaffolds to obtain unigenes with the least ns that could not be extended on either end.
for future analyses, the unigenes from the three samples were assembled again to acquire non-redundant unigenes  that were as long as possible.
the all-unigenes assembled from the three samples were compared with the ncbi non-redundant  protein database using blastx v <dig> .
<dig>  <cit>  with an e-value cut-off of 1e- <dig>  based on the results of the protein database annotation, blast2go  <cit>  was employed to obtain the functional classification of the unigenes based on go terms.
wego software  <cit>  was used to perform the go functional classification for all of the unigenes and to understand the distribution of the gene functions of this species at the macro level.
the kegg database   <cit>  was used to annotate the pathway of these unigenes.
ssr mining and primer design
we employed microsatellite  http://pgrc.ipk-gatersleben.de/misa/ for microsatellite mining.
in this study, the ssrs were considered to contain motifs with two to six nucleotides in size and a minimum of  <dig> contiguous repeat units.
based on misa results, primer <dig> v <dig>   was used to design the primer pairs with default setting, and the pcr product size ranging from  <dig> to  <dig> bp.
six varieties were selected to validated the polymorphism of  <dig> random ssr markers.
the six varieties included three varieties , which were all bred at the hebei institute of agricultural sciences, and the three varieties  used in this study.
the ssr data on the six varieties were obtained following the methods described by liang  <cit> .
RESULTS
sequencing and de novo assembly of solexa short reads
we generated  <dig> ,  <dig>  and  <dig>  million 100-bp paired-end reads for the jh <dig>  k <dig> and t <dig> varieties, encompassing  <dig> ,  <dig>  and  <dig>  gb of sequence data, respectively .
the gc contents of the three varieties were  <dig> %,  <dig> %, and  <dig> %, respectively.
assembling these reads produced  <dig> ,  <dig>  and  <dig>  unigenes for the jh <dig>  k <dig> and t <dig> varieties, respectively; only unigenes greater than  <dig> bp in length were further analysed.
the n <dig> values of these three unigenes were  <dig> bp,  <dig> bp and  <dig> bp, respectively.
after the final clustering,  <dig>  unigenes were obtained, with approximately equal contribution from varieties jh <dig> , k <dig> , and t <dig>   transcriptome shotgun assembly  database, http://www.ncbi.nlm.nih.gov/, accession numbers are jr540742-jr590649).
the length of the unigenes varied from  <dig> bp to  <dig> bp, with an average of  <dig> bp, and the n <dig> value was  <dig> bp.
the majority of the reads were in the range of 201- <dig> bp , and  <dig>  unigenes  were shorter than  <dig> k. these results should provide a sequence basis for future studies, such as gene cloning and transgenic studies.
characterisation of the unigenes
among the  <dig>  unigenes, the sequence directions of  <dig>  of the unigenes were determined using blastx against the ncbi non-redundant , swiss-prot, kegg, and clusters of orthologous groups  of protein databases with an e-value cut-off of 1e- <dig>  in addition, the protein coding regions of  <dig>  unigenes were predicted.
the unigenes were compared against the ncbi nr protein database using blastx.
among the  <dig>  unigenes,  <dig>   had at least one significant match with an e-value below 1e- <dig>  a total of  <dig>  unigenes had no significant matches to any known protein, the result that may be partly due to novel genes or highly divergent genes, or these unigenes could represent untranslated regions.
for validating redundancy of the data set with publicly available data, sequence similarity search was conducted against the ncbi unigene database ftp://ftp.ncbi.nlm.nih.gov/repository/unigene/arachis_hypogea/ using blastn with an e-value cut-off of 1e- <dig>  the results indicated that out of  <dig>  unigenes,  <dig>   showed significant similarity to publicly unigenes database.
all the information on the redundancy of the data set with the publicly available data were showed in the supplemental file .
we identified novel transcribed sequences using blastn and the ncbi mrna database sequences for peanut with an e-value cut-off of 1e- <dig>  a total of  <dig>   of the unigenes did not significantly match the mrna database and were, thus, considered putative novel transcribed sequences .
the lengths of the novel unigenes varied from  <dig> bp to  <dig> bp, with an n <dig> value of  <dig> bp.
among these novel unigenes, only  <dig>   were longer than  <dig> kb.
a total of  <dig>   of the unigenes had at least one significant match against the ncbi nr protein database.
rt-pcr was carried out to validate these expression distributions further by selecting  <dig> random novel unigenes .
the result indicated that all ten unigenes got right amplifications.
the new information provided by this study could be useful to further peanut research.
functional classification of the peanut unigenes
of the  <dig>  annotated unigenes, only  <dig>  of the unigenes could be assigned at least one go term, indicating that the peanut plant differs from model plants on genetic basis, and the search methodology of go analysis is not suitable for peanut.
these  <dig>  unigenes were grouped into  <dig> go functional categories , which are distributed under the three main categories of molecular function , biological process  and cellular components  .
within the molecular function category, genes encoding binding proteins  and proteins related to catalytic activity  were the most enriched.
proteins related to metabolic processes  and cellular processes  were enriched in the biological process category.
with regard to the cellular components category, the cell  and cell part  were the most highly represented categories.
a total of  <dig> genes were annotated with the category of lipid biosynthetic process , and  <dig> genes were classified into the fatty acid biosynthetic process group  in the next level.
further analyses of these genes should provide information about fatty acid metabolism in peanuts.
a total of  <dig>  unigenes were annotated with  <dig> pathways in the kegg database ; metabolic pathways were the most enriched , followed by plant-pathogen interaction pathways .
some pathways, such as the fatty acid metabolism pathway and fatty acid biosynthesis, the functions of which are clearly linked to the changes in the seed oil that take place during peanut ripening, would characterise in more detail in another paper .
ssr mining from the peanut seed transcriptome
microsatellite markers  are some of the most successful molecular markers in the construction of a peanut genetic map and in diversity analysis.
in this study,  <dig>  microsatellites were detected in  <dig>  unigenes, of which,  <dig> sequences contained more than  <dig> ssr.
the microsatellites included  <dig>   dinucleotide motifs,  <dig>   trinucleotide motifs,  <dig>  tetranucleotide motifs,  <dig>  pentanucleotide motifs and  <dig>  hexanucleotide motifs .
the most abundant repeat type was , followed by , , ,  and , respectively.
.
based on the  <dig>  ssrs,  <dig>  primer pairs were successfully designed using primer <dig> .
a total of  <dig> primer pairs  were randomly selected to validate these polymorphisms in six varieties.
all  <dig> of the markers yielded amplification products, and  <dig>  exhibited polymorphisms among the six varieties.
CONCLUSIONS
in this study, we performed a global characterisation of the peanut transcriptome by rna-seq using next-generation illumina sequencing.
we generated  <dig> - <dig>  million paired-end reads, comprising  <dig>  unigenes from three different varieties of peanut with different oil contents.
these unigenes were annotated with  <dig> go functional categories and  <dig> pathways.
a total of  <dig>  microsatellites were identified among the  <dig>  unigenes, and  <dig>  primer pairs were developed based on the sequence library.
these data will facilitate gene discovery and functional genomic studies in peanuts.
we gained insight into the complex transcriptome of the peanut and established a biotechnological platform for future research.
authors' contributions
jz carried out the peanut seed rna isolation and sequence data analyses and drafted the manuscript.
sl and jd designed the experiment and assisted in manuscript preparation.
sc, jw, zc, qz, xl and yl prepared the plant materials and co-designed the experiments.
all of the authors read and approved the final manuscript.
supplementary material
additional file 1
table s <dig>  the information on the redundancy of the data in this study with publicly available data.
click here for file
additional file 2
table s <dig>  the primer pairs were successfully designed by primer <dig> for all microsatellite.
click here for file
additional file 3
table s <dig>   <dig> random markers were used to validate the amplification and polymorphism.
click here for file
acknowledgements
this work was supported by the earmarked fund for china agriculture research system , the research program on quality-improvement and profit- incensement for major economic crops in hebei province  and the key basic research program of hebei province .

 the peanut, also known as the groundnut, is an important oilseed crop in the tropical and subtropical regions of the world. it is grown on six continents but mainly in asia, africa and america. peanuts are cultivated on million hectares worldwide, with a total global production of approximately million tons. china is the largest producer in the world, accounting for % of the total world production. peanuts have a desirable fatty acid profile and are rich in vitamins, minerals and bioactive materials, including several known heart-healthy nutrients, such as monounsaturated and polyunsaturated fatty acids, potassium, magnesium, copper niacin, arginine, fibre, α-tocopherol, folates, phytosterols, and flavonoids. indeed, peanut consumption has been associated with an improvement in the overall quality of the diet and nutrient. in china, almost 60% of the peanuts are used to produce peanut oil. peanut oil, due to its high monounsaturated fat content, is considered healthier than saturated oils and is resistant to rancidity. monounsaturated fat, much of which is oleic acid, is a healthy type of fat that has been implicated in the health of skin and has been demonstrated to reduce cardiovascular disease risk and/or risk factors in both epidemiological and clinical studies. the development of the peanut seed has been studied intensely to understand the physiological, biochemical, and molecular characteristics that determine the oil quality and their beneficial nutritional contributions. however, the development of the peanut seed is a complex process involving a cascade of biochemical changes, which involve the transcriptional modulation of many genes, yet little is known about these transcriptional changes and their regulation. to date, little research in this area has been reported. bi developed a seed cdna library for the peanut to analyse gene expression levels during seed development, and expressed sequence tags were sequenced and used for microarray analysis. recently, the development of next-generation high-throughput dna sequencing technology has provided a novel method for both mapping and quantifying transcriptomes. rna-seq technology has been successfully applied quite ubiquitously to species such as humans, yeast, mice, grape, arabidopsis, rice, soybeans, sesame, and sweetpotato. moreover, rna-seq data are highly reproducible, with few systematic discrepancies among technical replicates. the latest paired-end tag sequencing strategy of rna-seq further improves the dna sequencing efficiency and expands short-read lengths, providing a better depiction of transcriptomes. transcriptomic information is used in a wide range of biological studies and provides fundamental insight into biological processes and applications, such as the levels of gene expression, the gene expression profiles during development or after experimental treatments, gene discovery, ssr mining, and snp discovery. however, transcriptomic information is lacking for the peanut plant because this information is difficult to obtain and, to date, there has been little interest in such data. chen reported that the accumulation of seed oil in peanuts could be divided into three stages based on phenotype, namely, the initial accumulation stage, the fast accumulation stage and the steady accumulation stage. as we are interested in identifying genes that are expressed in the seed during the fast accumulation period, we carried out a global analysis of the peanut transcriptome during seed development using the illumina rna-seq method. we also present an overview of the rna-seq data for the peanut as a potential model for future rna-seq analyses and to establish a biotechnological platform for peanut research. methods sample preparation and sequencing three peanut varieties, which greatly differ in oil content but are similar in mature process, were used in this study. jihua, a variety with a high oil content, as determined in a field experiment in hebei, china, was bred at the hebei institute of agricultural sciences and is widely grown in northern china. kaixuan01-, a germplasm resource with a similar oil content, also determined in the above field experiment in hebei, was provided by the yantai institute of agricultural sciences in the shandong province of china. te, a germplasm resource with a low oil content, as determined in china, was also used. for each variety, rna was isolated from ten immature seeds of five plants, which were harvested at weeks after flowering during the growing season from a farm in hebei province. total rna was extracted using a previously described method. the rna quality and quantity were determined using an agilent bioanalyzer. beads coated with oligo were used to isolate poly mrna after the total rna was collected. fragmentation buffer was added to digest the mrna to produce short fragments. the first strand of cdna was synthesised using random hexamer primers, followed by synthesis of the second strand. the short fragments were purified with the qiaquick pcr purification kit for both end repair and the poly addition reaction. the purified dna libraries were amplified by pcr for cycles. finally, solexa hiseq™ was employed to sequence the libraries using pcr amplification. de novo assembly and analysis of illumina reads the samples were assembled with soapdenovo separately. the numbers of paired-end illumina reads of jh k and t were,, and, respectively. the reads were first combined to form longer fragments, i.e., contigs. the reads were then mapped back to the contigs, and the paired-end reads and contigs from the same transcript were assembled to form a longer sequence, with n for unknown sequences. paired-end reads were again used for gap filling of the scaffolds to obtain unigenes with the least ns that could not be extended on either end. for future analyses, the unigenes from the three samples were assembled again to acquire non-redundant unigenes that were as long as possible. the all-unigenes assembled from the three samples were compared with the ncbi non-redundant protein database using blastx v. with an e-value cut-off of 1e- based on the results of the protein database annotation, blast2go was employed to obtain the functional classification of the unigenes based on go terms. wego software was used to perform the go functional classification for all of the unigenes and to understand the distribution of the gene functions of this species at the macro level. the kegg database was used to annotate the pathway of these unigenes. ssr mining and primer design we employed microsatellite http://pgrc.ipk-gatersleben.de/misa/ for microsatellite mining. in this study, the ssrs were considered to contain motifs with two to six nucleotides in size and a minimum of contiguous repeat units. based on misa results, primer v was used to design the primer pairs with default setting, and the pcr product size ranging from to bp. six varieties were selected to validated the polymorphism of random ssr markers. the six varieties included three varieties, which were all bred at the hebei institute of agricultural sciences, and the three varieties used in this study. the ssr data on the six varieties were obtained following the methods described by liang.  sequencing and de novo assembly of solexa short reads we generated, and million 100-bp paired-end reads for the jh k and t varieties, encompassing, and gb of sequence data, respectively. the gc contents of the three varieties were %, %, and %, respectively. assembling these reads produced, and unigenes for the jh k and t varieties, respectively; only unigenes greater than bp in length were further analysed. the n values of these three unigenes were bp, bp and bp, respectively. after the final clustering, unigenes were obtained, with approximately equal contribution from varieties jh, k, and t transcriptome shotgun assembly database, http://www.ncbi.nlm.nih.gov/, accession numbers are jr540742-jr590649). the length of the unigenes varied from bp to bp, with an average of bp, and the n value was bp. the majority of the reads were in the range of 201- bp, and unigenes were shorter than k. these results should provide a sequence basis for future studies, such as gene cloning and transgenic studies. characterisation of the unigenes among the unigenes, the sequence directions of of the unigenes were determined using blastx against the ncbi non-redundant, swiss-prot, kegg, and clusters of orthologous groups of protein databases with an e-value cut-off of 1e- in addition, the protein coding regions of unigenes were predicted. the unigenes were compared against the ncbi nr protein database using blastx. among the unigenes, had at least one significant match with an e-value below 1e- a total of unigenes had no significant matches to any known protein, the result that may be partly due to novel genes or highly divergent genes, or these unigenes could represent untranslated regions. for validating redundancy of the data set with publicly available data, sequence similarity search was conducted against the ncbi unigene database ftp://ftp.ncbi.nlm.nih.gov/repository/unigene/arachis_hypogea/ using blastn with an e-value cut-off of 1e- the results indicated that out of unigenes, showed significant similarity to publicly unigenes database. all the information on the redundancy of the data set with the publicly available data were showed in the supplemental file. we identified novel transcribed sequences using blastn and the ncbi mrna database sequences for peanut with an e-value cut-off of 1e- a total of of the unigenes did not significantly match the mrna database and were, thus, considered putative novel transcribed sequences. the lengths of the novel unigenes varied from bp to bp, with an n value of bp. among these novel unigenes, only were longer than kb. a total of of the unigenes had at least one significant match against the ncbi nr protein database. rt-pcr was carried out to validate these expression distributions further by selecting random novel unigenes. the result indicated that all ten unigenes got right amplifications. the new information provided by this study could be useful to further peanut research. functional classification of the peanut unigenes of the annotated unigenes, only of the unigenes could be assigned at least one go term, indicating that the peanut plant differs from model plants on genetic basis, and the search methodology of go analysis is not suitable for peanut. these unigenes were grouped into go functional categories, which are distributed under the three main categories of molecular function, biological process and cellular components. within the molecular function category, genes encoding binding proteins and proteins related to catalytic activity were the most enriched. proteins related to metabolic processes and cellular processes were enriched in the biological process category. with regard to the cellular components category, the cell and cell part were the most highly represented categories. a total of genes were annotated with the category of lipid biosynthetic process, and genes were classified into the fatty acid biosynthetic process group in the next level. further analyses of these genes should provide information about fatty acid metabolism in peanuts. a total of unigenes were annotated with pathways in the kegg database; metabolic pathways were the most enriched, followed by plant-pathogen interaction pathways. some pathways, such as the fatty acid metabolism pathway and fatty acid biosynthesis, the functions of which are clearly linked to the changes in the seed oil that take place during peanut ripening, would characterise in more detail in another paper. ssr mining from the peanut seed transcriptome microsatellite markers are some of the most successful molecular markers in the construction of a peanut genetic map and in diversity analysis. in this study, microsatellites were detected in unigenes, of which, sequences contained more than ssr. the microsatellites included dinucleotide motifs, trinucleotide motifs, tetranucleotide motifs, pentanucleotide motifs and hexanucleotide motifs. the most abundant repeat type was, followed by,,, and, respectively.. based on the ssrs, primer pairs were successfully designed using primer. a total of primer pairs were randomly selected to validate these polymorphisms in six varieties. all of the markers yielded amplification products, and exhibited polymorphisms among the six varieties.  in this study, we performed a global characterisation of the peanut transcriptome by rna-seq using next-generation illumina sequencing. we generated - million paired-end reads, comprising unigenes from three different varieties of peanut with different oil contents. these unigenes were annotated with go functional categories and pathways. a total of microsatellites were identified among the unigenes, and primer pairs were developed based on the sequence library. these data will facilitate gene discovery and functional genomic studies in peanuts. we gained insight into the complex transcriptome of the peanut and established a biotechnological platform for future research. authors' contributions jz carried out the peanut seed rna isolation and sequence data analyses and drafted the manuscript. sl and jd designed the experiment and assisted in manuscript preparation. sc, jw, zc, qz, xl and yl prepared the plant materials and co-designed the experiments. all of the authors read and approved the final manuscript. supplementary material additional file 1 table s the information on the redundancy of the data in this study with publicly available data. click here for file additional file 2 table s the primer pairs were successfully designed by primer for all microsatellite. click here for file additional file 3 table s random markers were used to validate the amplification and polymorphism. click here for file acknowledgements this work was supported by the earmarked fund for china agriculture research system, the research program on quality-improvement and profit- incensement for major economic crops in hebei province and the key basic research program of hebei province.
these data will facilitate gene discovery and functional genomic studies of the peanut plant. we completed a successful global analysis of the peanut transcriptome using rna-seq, a large number of unigenes were assembled, and almost four thousand ssr primers were developed. based on sequence similarity search with known proteins, a total of genes were identified. in this study, we employed rna-seq to analyse the transcriptomes of the immature seeds of three different peanut varieties with different oil contents. in addition, this study provides insight into the complex transcriptome of the peanut and established a biotechnological platform for future research. among these unigenes, only unigenes were annotated with gene ontology functional categories. the peanut is an important oilseed crop in tropical and subtropical regions of the world.
 the peanut is an important oilseed crop in tropical and subtropical regions of the world. however, little about the molecular biology of the peanut is currently known. recently, next-generation sequencing technology, termed rna-seq, has provided a powerful approach for analysing the transcriptome, and for shedding light on the molecular biology of peanut.  in this study, we employed rna-seq to analyse the transcriptomes of the immature seeds of three different peanut varieties with different oil contents. a total of - million paired-end reads with lengths of bp were generated from the three varieties and unigenes were assembled with n of bp. based on sequence similarity search with known proteins, a total of genes were identified. among these unigenes, only unigenes were annotated with gene ontology functional categories. and unigenes mapped to pathways by searching against the kyoto encyclopedia of genes and genomes pathway database. in addition, microsatellite markers were developed in the unigene library, and pcr primers of ssr loci were used for validation of the amplification and the polymorphism.  we completed a successful global analysis of the peanut transcriptome using rna-seq, a large number of unigenes were assembled, and almost four thousand ssr primers were developed. these data will facilitate gene discovery and functional genomic studies of the peanut plant. in addition, this study provides insight into the complex transcriptome of the peanut and established a biotechnological platform for future research. 