Chickpea is an economically important legume crop with high nutritional value in human diets. Aluminium-toxicity poses a significant challenge for the yield improvement of this increasingly popular crop in acidic soils. The wild progenitors of chickpea may provide a more diverse gene pool for Al-tolerance in chickpea breeding. However, the genetic basis of Al-tolerance in chickpea and its wild relatives remains largely unknown. Here, we assessed the Al-tolerance of six selected wildCiceraccessions by measuring the root elongation in solution culture under control (0 µM Al3+) and Al-treatment (30 µM Al3+) conditions. Al-treatment significantly reduced the root elongation in all target lines compared to the control condition after 2-day’s growth. However, the relative reduction of root elongation in different lines varied greatly: 3 lines still retained significant root growth under Al-treatment, whilst another 2 lines displayed no root growth at all. We performed genome-wide identification of multidrug and toxic compound extrusion (MATE) encoding genes in theCicergenome. A total of 56 annotated MATE genes were identified, which divided into 4 major phylogeny groups (G1-4). Four homologues to lupinLaMATE(> 50% aa identity; namedCaMATE1-4) were clustered with previously characterised MATEs related to Al-tolerance in various other plants. qRT-PCR showed thatCaMATE2transcription in root tips was significantly up-regulated upon Al-treatment in all target lines, whilstCaMATE1was up-regulated in all lines except Bari2_074 and Deste_064, which coincided with the lines displaying no root growth under Al-treatment. Transcriptional profiling in fiveCicertissues revealed thatCaMATE1is specifically transcribed in the root tissue, further supporting its role in Al-detoxification in roots. This first identification of MATE-encoding genes associated with Al-tolerance inCicerpaves the ways for future functional characterization of MATE genes inCicerspp., and to facilitate future design of gene-specific markers for Al-tolerant line selection in chickpea breeding programs.
