Adding one more regulatory level, the fourfold increase in Epr3 transcript levels observed in the lhk1-1 mutant at 3 dpi and the increased epidermal expression of Epr3:GUS in lhk1-1 roots suggests that at early time points perception of cytokinin by LHK1 is important not only for controlling Nin levels43 but also for the feedback regulation of Epr3 in the epidermal root hairs where infection threads are initiated (Fig. 7g). The gene discussed is NIN; the disease is infection.