Abstract
BackgroundPeptide transporter (PTR) family whose member can transport di-/tripeptides and nitrate is important for plant growth and development. Although the rice (Oryza sativa L.) genome has been sequenced for a few years, a genomic survey, characterization and expression profile analysis of the PTR family in this species has not been reported.ResultsIn this study, we report a comprehensive identification, characterization, phylogenetic and evolutionary analysis of 84 PTR family members in rice (OsPTR) as well as their whole-life expression patterns. Chromosomal distribution and sequence analysis indicate that nearly 70% of OsPTR members are involved in the tandem and segmental duplication events. It suggests that genome duplication might be a major mechanism for expansion of this family. Highly conserved motifs were identified in most of the OsPTR members. Meanwhile, expression profile of OsPTR genes has been analyzed by using Affymetrix rice microarray and real-time PCR in two elite hybrid rice parents, Minghui 63 and Zhenshan 97. Seven genes are found to exhibit either preferential or tissue-specific expression during different development stages of rice. Under phytohormone (NAA, GA3 and KT) and light/dark treatments, 14 and 17 OsPTR genes are differentially expressed respectively. Ka/Ks analysis of the paralogous OsPTR genes indicates that purifying selection plays an important role in function maintenance of this family.ConclusionThese investigations add to our understanding of the importance of OsPTR family members and provide useful reference for selecting candidate genes for functional validation studies of this family in rice.
Highlights
Peptide transporter (PTR) family whose member can transport di-/tripeptides and nitrate is important for plant growth and development
The detailed information about the full-length cDNA, transcript, chromosomal position, BAC accession, gene structure for each OsPTR gene and characteristics of corresponding proteins can be found in Additional file 1
Considering the potential functional diversity of PTR members associated with nutrient transport and only a few PTR family members have been described in higher plants, it was timely and quite relevant for us to characterize the rice PTR family
Summary
Peptide transporter (PTR) family whose member can transport di-/tripeptides and nitrate is important for plant growth and development. PTR proteins in plants show significant sequence homology and contain several transmembrane (TM) regions, AtPTR2 (At2g02040) was the first identified di-/tripeptides transporter in Arabidopsis [7,8,9,10] and had high mRNA expression levels in 3-d-germinating seed, root and young leaf [8]. AtPTR1 (At3g54140) transported di-/ tripeptides with low selectivity as well as substrates lacking a peptide bond. AtPTR1 was expressed in the vascular tissue throughout the plant, indicative of a role in longdistance transport [10]. AtPTR5 (At5g01180) which mediated high-affinity transport of dipeptides was most likely supplying peptides to maturat-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
