Correlation of cytological and biochemical parameters with resistance and tolerance to Mycosphaerella graminicola in wheat

Abstract

This study investigated the infection process of Mycosphaerella graminicola and enzyme activities related to reactive oxygen species (ROS) or oxylipin biosynthesis in four French wheat cultivars with variable resistance to M. graminicola infection. At field level, cultivars Caphorn, Maxyl and Gen11 were susceptible, whereas Capnor showed high levels of quantitative resistance. Moreover, Capnor and Gen11 were tolerant, i.e., their yield was less affected by infection compared to non-tolerant Maxyl and Caphorn. These four cultivars were inoculated under laboratory conditions with the M. graminicola IPO323 reference strain. Cytological and biochemical responses were studied on collected first plantlet leaves and several features discriminated between cultivars. However, resistance and tolerance had no impact on the fungal infection process. Levels of lipoxygenase (LOX), peroxidase (PO) and glutathione-S-transferase (GST) activities were also compared with regard to cultivar resistance or tolerance to M. graminicola. LOX, PO and GST activities did not discriminate resistance and tolerance profiles, although a low level of PO in inoculated and non-inoculated plants could be associated with tolerance. In addition, cell necrosis correlated positively with LOX in non-tolerant cultivars, while mycelia surrounding stomata were positively correlated with PO in the resistant cultivar. GST activity presented correlations between cytological and biochemical parameters only for susceptible cultivars. Stomatal and direct penetration were positively correlated with GST activity in the susceptible non-tolerant cultivars, while these correlations were negative in the tolerant cultivar. When combining cytological and biochemical observations with resistance and tolerance profiles, for each cultivar and at each time point, cultivars could be classified in tight accordance with their previous field characterisation. Moreover, tolerance allowed us to distinguish susceptible cultivars when both biochemical and cytological parameters were considered together.

Genome-Wide Analyses of a Plant-Specific LIM-Domain Gene Family Implicate Its Evolutionary Role in Plant Diversification

“…Many plant-specific transcription factors evolved to control flower (Theissen et al 1996; Navaud et al 2007) and leaf development (Bartholmes et al 2012) to aid in their rapid radiation. To overcome the disadvantage of their immobility, plants also evolved many genes in response to various environmental stresses (Le et al 2011; Mizoi et al 2012).…”

Characterization of a Crabs Claw Gene in Basal Eudicot Species Epimedium sagittatum (Berberidaceae)

“…Functional studies and comparative expression analysis of CRC-like genes in different lineages, including monocots, early-diverging angiosperms, basal eudicots and core eudicots, indicate that CRC-like genes play crucial roles in gynoecium development [7,11,16–19]. For example, a CRC-like gene from the early-diverging angiosperm species Amborella trichopoda has been reported to partially complement carpel-related defects in the Arabidopsis crc-1 mutant [27].…”

“…There are six members of the YABBY gene family in Arabidopsis: FILAMENTOUS FLOWER (FIL), CRABS CLAW (CRC), INNER NO OUTER (INO), YABBY2 (YAB2), YAB3 and YAB5 [7,11,16]. The proteins they encode are composed of an N -terminal zinc finger domain and a C -terminal helix-loop-helix (YABBY domain) [7,15].…”

“…The proteins they encode are composed of an N -terminal zinc finger domain and a C -terminal helix-loop-helix (YABBY domain) [7,15]. Phylogenetic analysis of YABBY genes from extant angiosperm species strongly supports a sister relationship between INO - like genes and the common ancestor of CRC-like and FIL-like genes [16]. In Arabidopsis, the “vegetative” YABBYs (FIL, YAB2, YAB3 and YAB5) are expressed in abaxial cells of lateral organ primordia, where they control leaflet initiation and laminar growth [11].…”

Are ineffective defence reactions potential target for induced resistance during the compatible wheat-powdery mildew interaction?

“…LOX (EC 1.13.11.12), OXO (EC 1.2.3.4), GST (EC 2.5.1.13) and PAL (EC 4.3.1.24) activities were measured as described by Randoux et al (2006), El-Chartouni et al (2011) and Reignault et al (2001) respectively.…”