Pentose reductase with a broad substrate affinity involved in pentose catabolism. Has highest reductase activities with L-arabinose and D-xylose as substrates, and displays much lower activities with D-ribose, D-galactose and D-glucose. Has highest dehydrogenase activity with L-arabitol as substrate, followed by xylitol and D-sorbitol. May be responsible for the first step of the L-arabinose catabolic pathway. Overexpressed during growth on both D-xylose or L-arabinose compared to D-glucose. Significantly expressed during late stages of infection of barley leaves. Belongs to the aldo/keto reductase family.