| Resistance shown by an entire plant species to a specific parasite or pathogen is knownas nonhost resistance, and is durable and expressed by every plant towards the majority ofpotentially pathogenic microbes. Phytophthora sojae, a devastating oomycete pathogen ofsoybean, is evolutionally and pathologically distant from true fungi. Traditional resistantsoybean cultivars are not durably effective due to rapid virulence variation of P. sojae. Thus,research on nonhost resistance can not only contribute to understanding the mechanism ofoomycete and plant interaction but also be a novel source of improving crop plants againstdiseases caused by host-adapted pathogens.In this study P. sojae and its nonhost Arabidopsis thaliana were employed to understandthe basis of nonhost resistance in plants against oomycete pathogens，and some results arelisted as follow:1. An A. thaliana T-DNA insertional mutant1822that was susceptible to P. sojaeinfection was identified from several candidates；2. By TAIL-PCR, the insertion flanking sequences of two T-DNA insertion sites (PectinAcetyl Esterasesgene AtPAE and LRR Receptor Kinase AtRCH1) were cloned from1822andRT-PCR (Reverse Transcription PCR) indicated that AtPAE was transcriptionally blocked byT-DNA insertion;3. Infection assays of stable transformants silenced with individual target genes showedthat silencing of AtPAE mediated increased susceptibility of the mutant1822to P. sojae;4. Ectopic expressing AtPAE-GFP fusion protein localized exclusively in the cell wall ofNicotiana benthamiana leaves, and transciently expression of AtPAE on N. benthamianaleaves did not improve resistance against P. paracitica;5. AtPAE-GFP fusion protein localized exclusively in the peripheral region of A. thalianacells, and the localization in the adult leave cells was not affected by pathogen invasion.Above all, AtPAE probably functions in the cell wall and is likely involved in thenonhost resistance to the oomycete pathogen P. sojae. |
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