Characterizing the growth and gene expression profile of Phytophthora agathidicida in (the soils of) alternate land managements

Abstract

New Zealand kauri (Agathis australis) is an iconic tree species of cultural significance, and an important forest ecosystem engineer and timber resource. Phytophthora agathidicida, an aggressive soilborne pathogen causes dieback in kauri trees of all ages. This pathogen infects roots and damages tissues that distribute nutrients and water within the tree. Surveillance studies between 2008 and 2017 have shown the widespread distribution of the disease in many of the regions where kauri is established illustrating the threat to the long‐term survival of the species. This study attempts to interrogate the growth response and gene expression profile of P. agathidicida exposed to different soils taken from alternate land management regimes within and adjacent to kauri forests (indigenous kauri forest, pastureland and commercial pine forest). Our aim was to assess whether soils from these contrasting land-uses are conducive, suppressive or neutral to the pathogen growth, with implications for pathogen spread and establishment beyond kauri forests. Preliminary results suggest that there is a difference in sporangia production with time and between soils in association with observed variation in gene expression. Details of the most abundant gene classes, their associated molecular functions and biological processes, expressed with respect to the life stage development and at different soil conditions will be presented.