Strategy for obtaining the entire coding cDNA sequence of the CsMRP4 gene. a Whole cDNA (4410 bp) was confirmed by combining 5′-RACE PCR and DNA-walking. The used primers are listed in Additional file 1: Table S1. UPM, GSP1, GSP2, and NGSP were primers used for 5′-RACE PCR. CsMRP4-I-F/R and CsMRP4-II-F/R primers were designed for amplification of CsMRP4-I and II fragments through DNA-walking. SF1, SR1, SF2, SR2, and F3 were used for sequencing. b Amplification of the missing 5′-end using RACE-PCR. c RACE-PCR products were confirmed using nested-PCR with UPM and NGSP primers. d The putative CsMRP4 (GenBank ID: GAA49862.1) was confirmed by DNA-walking. (TIFF 3873 kb)