Identification of candidate signaling genes including regulators of chromosome condensation 1 protein family differentially expressed in the soybean–Phytophthora sojae interaction

Abstract

Stem and root rot caused by the oomycete pathogen, Phytophthora sojae, is a serious soybean disease. Use of Phytophthora resistance genes (Rps) in soybean cultivars has been very effective in controlling this pathogen. Resistance encoded by Rps genes is manifested through activation of defense responses. In order to identify candidate signaling genes involved in the expression of Phytophthora resistance in soybean, a cDNA library was prepared from infected etiolated hypocotyl tissues of a Phytophthora resistant soybean cultivar harvested 2 and 4 h following P. sojae inoculation. In silico subtraction of 101,833 expressed sequence tags (ESTs) originating from unstressed cDNA libraries from 4,737 ESTs of this library resulted in identification of 204 genes that were absent in the unstressed libraries. Of the 204 identified genes, seven were P. sojae genes. Putative function of 91 of the 204 genes could not be assigned based on sequence comparison. Macroarray analyses of all 204 genes led to identification of 60 genes including 15 signaling-related soybean genes and three P. sojae genes, transcripts of which were induced twofold in P. sojae-infected tissues as compared to that in water controls. Eight soybean genes were down-regulated twofold following P. sojae infection as compared to water controls. Differential expression of a few selected genes was confirmed by conducting Northern and RT-PCR analyses. We have shown that two putative regulators of chromosome condensation 1 (RCC1) family proteins were down-regulated in the incompatible interaction. This observation suggested that the nucleocytoplasmic transport function for trafficking protein and non-coding RNA is suppressed during expression of race-specific Phytophthora resistance. Characterization of a cDNA library generated from tissues harvested almost immediately following P. sojae-infection of a resistant cultivar allowed us to identify many candidate signaling genes that are presumably involved in regulating the expression of defense-related pathways for expression of Phytophthora resistance in soybean.

Carica papaya Genes Regulated by Phytophthora palmivora: A Model System for Genomic Studies of Compatible Phytophthora-plant Interactions

“…2), Ros et al [29] observed up-regulation of another β-1,3 glucanase encoding gene in S. tuberosum following inoculation with P. infestans. Several genes encoding cytochrome P450 proteins were, like Cp35, reported to be up-regulated by Phytophthora in a number of studies [26,27,29,32]. Other genes encoding HIR proteins regulated by Phytophthora were unidentified (Table 3).…”

“…Multiple studies have reported differential gene expression of compatible and incompatible Phytophthora-host-interactions using various approaches, including microarray analysis and suppression subtractive hybridization. Phytophthora-responsive genes have been identified in soybean [26,27], potato [28,29], tomato [30], Fagus sylvatica [31] and Arabidopsis thaliana [32]. These studies confirmed pathogen regulation of host genes and provide a database that may be used to distinguish effector targets from genes regulated by Phytophthora's MAMPs.…”

Molecular response to the pathogen Phytophthora sojae among ten soybean near isogenic lines revealed by comparative transcriptomics

“…During this process, two putative regulators of the chromosome condensation 1 ( RCC1 ) gene family are down-regulated during the incompatible interaction [27]. Besides SA, exogenous treatment of 1-aminocyclopropane-1-carboxylic acid (ACC, a precursor of ET) has been shown to enhance resistance while applications of GA and ABA induce susceptibility, highlighting the complexity of phytohormone signaling pathways in response to attack by P. sojae [26,28,29].…”

Single plant selection for improving root rot disease (Phytophthora medicaginis) resistance in Chickpeas (Cicer arietinum L.)

“…Polygenic resistance mechanisms were reported for chickpea Fusarium wilt (Upadhyaya et al 1983) and other crops (Götesson et al 2002;Narayanan et al 2009;Li et al 2010). If many genes were involved in imparting resistance to PRR, selections should be made from very advanced generations (Falconer et al 1996), otherwise both resistant and susceptible components would get progressed in the absence of a selection pressure.…”

“…Götesson et al (2002) identified up to 19-member gene family of endopolygalacturonase in Phytophthora cinnamomi. However, genomic level studies during the early stages (2-4 h) of infection of phytophthora in soybean activated more than 195 genes (Narayanan et al 2009) and eight Quantitative Trait Loci (QTL) for PRR tolerance (Li et al 2010).…”