UDP‐glucosyltransferase UGT84A2/BRT1 is required for Arabidopsis nonhost resistance to the Asian soybean rust pathogen Phakopsora pachyrhizi

Abstract

SummaryNonhost resistance (NHR) of plants to fungal pathogens comprises different defense layers. Epidermal penetration resistance of Arabidopsis to Phakopsora pachyrhizi requires functional PEN1, PEN2 and PEN3 genes, whereas post-invasion resistance in the mesophyll depends on the combined functionality of PEN2, PAD4 and SAG101. Other genetic components of Arabidopsis post-invasion mesophyll resistance remain elusive.We performed comparative transcriptional profiling of wild-type, pen2 and pen2 pad4 sag101 mutants after inoculation with P. pachyrhizi to identify a novel trait for mesophyll NHR. Quantitative reverse transcription-polymerase chain reaction (RT-qPCR) analysis and microscopic analysis confirmed the essential role of the candidate gene in mesophyll NHR.UDP-glucosyltransferase UGT84A2/bright trichomes 1 (BRT1) is a novel component of Arabidopsis mesophyll NHR to P. pachyrhizi. BRT1 is a putative cytoplasmic enzyme in phenylpropanoid metabolism. BRT1 is specifically induced in pen2 with post-invasion resistance to P. pachyrhizi. Silencing or mutation of BRT1 increased haustoria formation in pen2 mesophyll. Yet, the brt1 mutation did not affect NHR to P. pachyrhizi in wild-type plants.We assign a novel function to BRT1, which is important for post-invasion NHR of Arabidopsis to P. pachyrhizi. BRT1 might serve to confer durable resistance against P. pachyrhizi to soybean.

Interspecies gene transfer provides soybean resistance to a fungal pathogen

“…Fold change in gene expression in P. pachyrhizi ‐inoculated versus mock‐treated genotypes is shown. Expression values of BRT1 (Langenbach et al ., ) are given for reference.…”

“…Using comparative, genomewide transcriptome profiling we recently identified the gene for UDP glycosyltransferase 84A2 (UGT84A2 or bright trichomes (BRT) 1) as a critical component of Arabidopsis postinvasion NHR to P. pachyrhizi (Langenbach et al ., ). Here, we extended our analysis to genes transcriptionally coregulated with BRT1 .…”

“…phytoalexin‐deficient (PAD) 4 and senescence‐associated gene (SAG) 101 contribute to postinvasion resistance of Arabidopsis to these fungi. Consequently, the pen2 pad4 sag101 triple mutant, but not single mutant pen2 with intact postinvasion NHR (Langenbach et al ., ; Lipka et al ., ), facilitates sporulation of Bgh and E. pisi . pen2 pad4 sag101 also allows enhanced formation of P. pachyrhizi haustoria, which are characteristic feeding organs of plant parasitic fungi (Langenbach et al ., ).…”

“…Consequently, the pen2 pad4 sag101 triple mutant, but not single mutant pen2 with intact postinvasion NHR (Langenbach et al ., ; Lipka et al ., ), facilitates sporulation of Bgh and E. pisi . pen2 pad4 sag101 also allows enhanced formation of P. pachyrhizi haustoria, which are characteristic feeding organs of plant parasitic fungi (Langenbach et al ., ). NHR also involves activity of genes in the phenylpropanoid pathway of plant secondary metabolism and key hormones of plant immunity such as salicylic acid and jasmonate (Langenbach et al ., ; Loehrer et al ., ; Mellersh and Heath, ; Shafiei et al ., ).…”

Arabidopsis late blight: infection of a nonhost plant byAlbugo laibachiienables full colonization byPhytophthora infestans

“…Co‐infection assays with the Asian soybean rust were performed on detached leaves with P . pachyrhizi isolate PPUFV02 as described (Langenbach et al ., ). Briefly, uredospores from P .…”