Genome-wide identification and expression characterization of ABCC-MRP transporters in hexaploid wheat.

Kaushal K Bhati,Shrikant Mantri,Jagdeep Kaur,Sipla Aggarwal,Shivani Sharma,Ajay K Pandey,Mandeep Kaur,Vishnu Shukla

doi:10.3389/fpls.2015.00488

Kaushal K Bhati, Shrikant Mantri + Show 6 more

Open Access

https://doi.org/10.3389/fpls.2015.00488

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Abstract

The ABCC multidrug resistance associated proteins (ABCC-MRP), a subclass of ABC transporters are involved in multiple physiological processes that include cellular homeostasis, metal detoxification, and transport of glutathione-conjugates. Although they are well-studied in humans, yeast, and Arabidopsis, limited efforts have been made to address their possible role in crop like wheat. In the present work, 18 wheat ABCC-MRP proteins were identified that showed the uniform distribution with sub-families from rice and Arabidopsis. Organ-specific quantitative expression analysis of wheat ABCC genes indicated significantly higher accumulation in roots (TaABCC2, TaABCC3, and TaABCC11 and TaABCC12), stem (TaABCC1), leaves (TaABCC16 and TaABCC17), flag leaf (TaABCC14 and TaABCC15), and seeds (TaABCC6, TaABCC8, TaABCC12, TaABCC13, and TaABCC17) implicating their role in the respective tissues. Differential transcript expression patterns were observed for TaABCC genes during grain maturation speculating their role during seed development. Hormone treatment experiments indicated that some of the ABCC genes could be transcriptionally regulated during seed development. In the presence of Cd or hydrogen peroxide, distinct molecular expression of wheat ABCC genes was observed in the wheat seedlings, suggesting their possible role during heavy metal generated oxidative stress. Functional characterization of the wheat transporter, TaABCC13 a homolog of maize LPA1 confirms its role in glutathione-mediated detoxification pathway and is able to utilize adenine biosynthetic intermediates as a substrate. This is the first comprehensive inventory of wheat ABCC-MRP gene subfamily.

Highlights

ATP-binding cassette transporter (ABC) proteins are found in all living organisms and constitute one of the largest known superfamily (Henikoff et al, 1997; Rea, 1999)
Our refined searches resulted in identification of 18 ABCC subclass proteins from wheat, hereafter referred as TaABCC1–TaABCC18
The nomenclature was based on the guidelines those are widely accepted for plant ABC protein (Verrier et al, 2008)

Summary

Introduction

ATP-binding cassette transporter (ABC) proteins are found in all living organisms and constitute one of the largest known superfamily (Henikoff et al, 1997; Rea, 1999). The ABCC subfamily of these transporters classically referred as multi drug resistance associated proteins (MRPs) have been best characterized in Arabidopsis. Each of these MRP proteins contains at least one highly conserved ATPase domain as an energy provider (∼200 aa residues long) referred as nucleotide binding domains (NBD). MRP proteins usually contain two repeats of transmembrane (TMD) and NBD represented as TMD1-NBD1-TMD2-NBD2 (Klein et al, 2006)

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