Genome-wide Analysis Of The AAAP Gene Family In Medicagotruncatula And Cicer Arietinum

The amino acid/auxin permease(AAAP)gene family plays an important role in the long-distance amino acid transport pathway and takes part in various stages of plant growth and stress responses.Leguminous crops are very important economic crops,which are widely planted all over the world and are one of the important sources of protein uptake.Medicago truncatula is a model plant of the Leguminous,which have a simple genome and high transformation efficiency,are often used in genomics research.Chickpea(Cicer arietinum L.)is an excellent leguminous crop with abundant nutrition.In recent years,Chickpea has attracted widely attention because of its strong drought and barren tolerance ability.Here,we systematically predicted the characteristics and functions of AAAP family in M.truncatula and Chickpea by using genomic sequence information and bioinformatics methods through phylogenetic analysis,gene structure analysis and conserved domain analysis.The results are as follows:1.We identified 86 putative MtAAAP family members and 70 CarAAAP family members by using the genome sequence information.The basic information and physicochemical characteristics were determined,including the length of open reading frame,amino acid length,isoelectric point,molecular weight,average hydrophilic coefficient,the number of introns and exons,etc.2.Based on phylogenetic,gene structure and conserved motif analysis,these AAAP genes were categorized into eight distinct subfamilies,comprise AAP?LHT?GAT?AUX?ProT?ANT?ATLa and ATLb.3.The AAAP genes were mapped on eight chromosomes in M.truncatula and Chickpea.However,the distribution of AAAP gene family members was not uniform,and the number of AAAP gene family members was the least on chromosome 2,the highest on chromosome 3 in Medicago truncatula,and the least on chromosome 1 and the highest on chromosome 4 in Chickpea.4.Duplication events appeared widely in AAAP gene family.In Medicago,52.3%(45/86)of genes duplicated,with 19 and 21 pairs of AAAP genes showing segment and tandem duplication events,respectively.In Chickpeas,60%(42/70)of genes duplicated,with 15 and 20 pairs of AAAP genes showing segment and tandem duplication events,respectively.5.Further analysis of the synonymous and heterosexual substitution ratios of these duplicate gene pairs showed that the Ka/Ks ratio of AAAP gene in M.truncatula was mainly 0.3,Ka/Ks in chickpea have two concentration domains of 0.2 and 0.9.Ratio of Ka/Ks indicated that duplicated genes were mainly underwent purifying selection in the evolution history,and possess very important biological functions.6.Analysis of RNA-seq data showed that AAAP genes exhibited specific expression patterns among different tissues and abiotic stress in M.truncatula and chickpea,indicating that AAAP members were involved in plant developmental regulation and stress responses.Expression analysis of 16 MtAAAP genes under abiotic stress were verified by qRT-PCR.