<p>(a) pH of the medium (white circles) and ammonia accumulation (small black circles) during growth of the wild type strain Guy11 in liquid non-buffered TNK-YE medium. (b) pH of the infection zone during plant infection by the wild type Guy11 strain; detached barley (black) or rice (grey) leaves were infected with drops of conidia and the pH was recorded over time using a surface electrode. Results are the average of three independent experiments and standard deviations are shown.</p