In vitro and in vivo quantification of elicitin expression in Phytophthora cinnamomi

Abstract

The differential expression of four Phytophthora cinnamomi elicitin genes was analysed by Real Time RT-PCR. In in vitro cultures, the α-cinnamomin gene showed the highest level of expression, the β-cinnamomin gene ( β-cin) was the most inducible, and the HAE transcripts were in low abundance. Transcription of all the elicitins was active during the active growth of the pathogen when infecting cork oak ( Quercus suber) roots, and as host colonization progressed, the level of β-cin expression fell, while that of α-cin rose. In an antisense transgenic strain, the silencing of β-cin also negatively affected the expression of other elicitin genes in the cluster. The reduced in planta growth of the β-cin knock-out is related to the altered pattern of elicitin gene expression, supporting the idea that one of the functions of elicitins is related, directly or indirectly, with pathogenesis.