Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis

Abstract

Due to the economic importance of gummosis disease for the citriculture, studies on P. parasitica-Citrus interaction comprise a significant part in the Brazilian Citrus genome data bank (CitEST). Among them, two cDNA libraries constructed from two different growth conditions of the P. parasitica pathogen are included which has generated the PP/CitEST database (CitEST -Center APTA Citros Sylvio Moreira/IAC-Millennium Institute). Through this genomic approach and clustering analyses the following has been observed: out of a total of 13,285 available in the Phytophthora parasitica database, a group of 4,567 clusters was formed, comprising 2,649 singlets and 1,918 contigs. Out of a total of 4,567 possible genes, only 2,651 clusters were categorized; among them, only 4.3% shared sequence similarities with pathogenicity factors and defense. Some of these possible genes (103) corresponding to 421 ESTs, were characterized by phylogenetic analysis and discussed. A comparison made with the COGEME database has shown homology which may be part of an evolutionary pathogenicity pathway present in Phytophthora and also in other fungi. Many of the genes which were identified here, which may encode proteins associated to mechanisms of citrus gummosis pathogenicity, represent only one facet of the pathogen-host Phytophthora -Citrus interaction.

Infection of Arabidopsis thaliana by Phytophthora parasitica and identification of variation in host specificity

“…Phytophthora parasitica is emerging as a model oomycete species for several reasons: (i) the increasing amount of genetic and genomic resources, including the generation of expressed sequence tag (EST) sequences during pathogen development and plant infection (Kebdani et al ., 2010; Le Berre et al ., 2008; Panabieres et al ., 2005; Rosa et al ., 2007; Shan et al ., 2004; Skalamera et al ., 2004); (ii) a large‐insert genomic library that has allowed the confirmation of the P. parasitica genome size as 95.5 Mb, which is similar to that of P. sojae (Shan and Hardham, 2004); (iii) its genetic tractability (Bottin et al ., 1999; Gaulin et al ., 2002); and (iv) the availability of genomic tools. Over 80% of the EST sequences obtained were also found within the P. sojae , P. ramorum or P. infestans genomes.…”

Transcriptome profile of Carrizo citrange roots in response toPhytophthora parasiticainfection

“…They have shown significant induction of key defense genes in susceptible rootstock whereas little or no changes in the expression level of tested defense genes in the resistant rootstocks were observed by them in response to pathogen (Dalio et al, 2017). Similarly, on the pathogen side, transcriptional profiling of P. parasitica during citrus gummosis was conducted to identify pathogenicity factors during infection (Rosa et al, 2007). These reports of citrus-Phytophthora interactions are either confined to the above ground infections where mostly leaf tissues were used for transcriptome analysis or restricted to few defense related genes in roots, but so far, no study has been done to determine whole transcriptional profiling of citrus roots during Phytophthora root rot.…”

Genetic tools and strategies for citrus breeding aiming at resistant rootstocks to gummosis disease

“…These genes are also regulated by plant hormones, including salicylic acid (SA) and abscisic acid (ABA) (Fernandes et al 2009;Boava et al 2011a;Boava et al 2011b). In addition, genes associated with pathogenicity, including effectors, host colonization and defense in the host, were reported in P. nicotianae (Rosa et al 2007).…”