Whole-transcriptome survey of the putative ATP-binding cassette (ABC) transporter family genes in the latex-producing laticifers of Hevea brasiliensis.

Nie Zhiyi,Dai Longjun,Kang Guijuan,Li Yu,Zeng Rizhong,Chunxian Chen

doi:10.1371/journal.pone.0116857

Nie Zhiyi, Dai Longjun + Show 4 more

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https://doi.org/10.1371/journal.pone.0116857

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Abstract

The ATP-binding cassette (ABC) proteins or transporters constitute a large protein family in plants and are involved in many different cellular functions and processes, including solute transportation, channel regulation and molecular switches, etc. Through transcriptome sequencing, a transcriptome-wide survey and expression analysis of the ABC protein genes were carried out using the laticiferous latex from Hevea brasiliensis (rubber tree). A total of 46 putative ABC family proteins were identified in the H. brasiliensis latex. These consisted of 12 ‘full-size’, 21 ‘half-size’ and 13 other putative ABC proteins, and all of them showed strong conservation with their Arabidopsis thaliana counterparts. This study indicated that all eight plant ABC protein paralog subfamilies were identified in the H. brasiliensis latex, of which ABCB, ABCG and ABCI were the most abundant. Real-time quantitative reverse transcription-polymerase chain reaction assays demonstrated that gene expression of several latex ABC proteins was regulated by ethylene, jasmonic acid or bark tapping (a wound stress) stimulation, and that HbABCB15, HbABCB19, HbABCD1 and HbABCG21 responded most significantly of all to the abiotic stresses. The identification and expression analysis of the latex ABC family proteins could facilitate further investigation into their physiological involvement in latex metabolism and rubber biosynthesis by H. brasiliensis.

Highlights

The ATP-binding cassette (ABC) protein family, especially the intrinsic membrane subfamilies, mediates a large number of fundamental cellular functions and processes that utilize ATP hydrolysis to energize the transport of solutes across membranes
Proteomic data from previous studies have demonstrated that A. thaliana ABCB26/TAP1 is localized to the chloroplast [50] and the results of this study suggest that the latex HbABCB26, a homolog of At ABCB26/TAP1, might possibly be localized to the Frey-Wyssling particles, which are very specialized chromoplasts in rubber tree latex [51]
The results demonstrated that the most of the latex ABC transporter genes were controlled by Ethrel, methyl jasmonate (Me-jasmonic acid (JA)) or bark tapping to varying degrees (S5 Table), among which HbABCB15, HbABCB19, HbABCD1 and HbABCG21 were significantly up-regulated by the three different stimulations

Summary

Introduction

The ATP-binding cassette (ABC) protein family, especially the intrinsic membrane subfamilies, mediates a large number of fundamental cellular functions and processes that utilize ATP hydrolysis to energize the transport of solutes across membranes. These include substrate translocation, lipid trafficking, protein targeting and phytohormone transport [1,2,3,4,5], etc. Characterization of the ABC transporters in the laticifers would help reveal the physiological and molecular processes underlying latex metabolism and NR biosynthesis in rubber trees. This research provides valuable information for further investigations into the physiological roles of the ABC transporters during latex metabolism and NR biosynthesis in rubber trees

Materials and Methods

Concluding Remarks