Transcriptional activator of the arabinanolytic system. Involved in the regulation of extracellular arabinanolytic genes and in the regulation of the intracellular activities of L-arabinose catabolic genes in the pentose catabolic pathway (PCP) in response to the presence of L-arabinose. Impairs growth on L-arabinose, but only a small growth reduction on L-arabitol. Belongs to the xlnR/xlr1 family. araR subfamily.