Characterization of Defense Signaling Pathways of Brassica napus and Brassica carinata in Response to Sclerotinia sclerotiorum Challenge

Abstract

Canola (Brassica napus L.) is an agriculturally and economically important crop in Canada, and its growth and yield are frequently influenced by fungal pathogens. Sclerotinia sclerotiorum is among those fungal pathogens and causes stem rot disease in B. napus whereas it has been reported that Brassica carinata is moderately tolerant to S. sclerotiorum. Jasmonic acid/ethylene (JA/ET) and salicylic acid (SA) are phytohormones that are known to be involved in plant disease responses. To investigate the defense signaling cascades involved in the interaction of B. napus and B. carinata with S. sclerotiorum, we examined the expression of five orthologs of B. napus genes involved in JA/ET or SA signaling pathways using quantitative RT-PCR. Our results indicated that there are differences in the timing of JA/ET and SA signaling pathways between B. napus and B. carinata. Our results in these two Brassica species also support previous observations that necrotrophic pathogens trigger JA/ET signaling in response to infection. Finally, we observed that transgenic canola expressing 1-aminocyclopropane-1-carboxylate-deaminase producing low levels of ET was relatively more susceptible to S. sclerotiorum than its wild-type counterpart, suggesting that ET inhibits S. sclerotiorum-induced symptom development.

Virus-Induced Gene Silencing of a Putative Glutathione S-Transferase Gene Compromised Ol-1-Mediated Resistance against Powdery Mildew in Tomato

“…Plants have evolved defense mechanisms to protect themselves against these pathogens (Bi et al 2011;Yang et al 2010). The R gene-mediated resistance response is an important defense mechanism in which many gene products forms the signal transduction pathway (Leng et al 2010;Zhang et al 2010;Zhao et al 2010).…”

Expression Analysis of Defense-Related Genes in Cotton (Gossypium hirsutum) after Fusarium oxysporum f. sp. vasinfectum Infection and Following Chemical Elicitation using a Salicylic Acid Analog and Methyl Jasmonate

“…The pivotal role of reactive oxygen species (ROS) and of plant hormones such as salicylic acid (SA) and jasmonate (JA) in the regulation of innate immune response is well established (Glazebrook 2005; Berrocal-Lobo and Molina 2008; Bari and Jones 2009;Li et al 2010;Yang et al 2010). Although SA and JA-mediated responses were initially considered to be dichotomous and independent of each other, we now know that they highly interact (Beckers and Spoel 2006;Mur et al 2006;Spoel and Dong 2008;Verhage et al 2010) acting synergistically, or antagonistically, which depends on the system between host/pathogens (Kachroo and Kachroo 2007).…”

“…Although SA and JA-mediated responses were initially considered to be dichotomous and independent of each other, we now know that they highly interact (Beckers and Spoel 2006;Mur et al 2006;Spoel and Dong 2008;Verhage et al 2010) acting synergistically, or antagonistically, which depends on the system between host/pathogens (Kachroo and Kachroo 2007). Furthermore, this cross-talk between SA and JA signalling pathways is specific to the pathogen strain and its lifestyle (Thomma et al 2001;Glazebrook 2005;Spoel et al 2007;Yang et al 2010). The final outcome of the induced defense responses is the consistent expression and accumulation of pathogenesisrelated (PR) proteins .…”

“…These are currently organized in 17 families, occur widely in the plant kingdom, and constitute a major component of plant defense responses (van Loon et al 2006). SAR is proposed to be a result of the fine-tuned induction of PR genes and can be initiated by exogenous treatments with SA and other related chemical inducers like 2,6 dichloroisotonic acid and benzo(l,2,3) thiadiazole-7-cardothioic acid S-methylester (Bion®, BTH) (Gozzo 2003;Yang et al 2010). Moreover, JA controls the expression of several PR genes (McDowell and Dangl 2000;Glazebrook 2005;Demetriou et al 2010).…”

Protein extract of tobacco expressing StoVe1 gene inhibits Verticillium dahliae proliferation

“…The Ve gene products are predicted to be cell surface receptor proteins based on conserved amino acid sequence motifs and the receptor protein plays a role in the recognition of pathogen-derived molecules (Kawchuk et al 2001). When plants are challenged by pathogens, complex integrated sets of defence responses, both constitutive and induced, are triggered and mediated by high affinity plant cell surface receptors (Dong 1998;Kunkel & Brooks 2002;Nishimura & Dangl 2010;Yang et al 2010;Antonios et al 2012). Then, the plants rapidly express nucleic acid binding leucine-rich repeat (NB-LRR) genebased recognition patterns to establish a series of effector-triggered immunity reactions (Jones & Dangl 2006;Lacombe et al 2010).…”