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. Reduces growth on L-arabinose, xylitol, arabinan, Arabic gum, arabinogalactan and apple pectin, and shows poor growth on L-arabitol. Belongs to the xlnR/xlr1 family. araR subfamily.