Veinal-mesophyll interaction under biotic stress.
According to microscopic observations, germinating hyphae of Botrytis cinerea, though easily penetrating Mesembryanthemum crystallinum mesophyll tissue, are limited in growth in mid-ribs and only occasionally reach vascular bundles. In mid-ribs of C3 and CAM leaves, we found significantly lower rbcL (large RubisCO subunit) abundance. Moreover, in CAM leaves, minute transcript contents for pepc1 (phosphoenolpyruvate carboxylase) and nadpme1 (malic enzyme) genes found in the mid-ribs suggest that they perform β-carboxylation at a low rate. The gene of the main H2O2-scavenging enzyme, catL (catalase), showed lower expression in C3 mid-rib parts in comparison to mesophyll. This allows maintenance of higher H2O2 quantities in mid-rib parts. In C3 leaves, pathogen infection does not impact photosynthesis. However, in CAM plants, the expression profiles of rbcL and nadpme1 were similar under biotic stress, with transcript down-regulation in mid-ribs and up-regulation in mesophyll (however, in case of rbcL not significant). After B. cinerea infection in C3 plants, transcripts for both antioxidative proteins strongly increased in mid-ribs, but not in mesophyll. In infected CAM plants, a significant transcript increase in the mesophyll was parallel to its decrease in the mid-rib region (however, in the case of catL this was not significant). Pathogen infection modified the expression of carbon and ROS metabolism genes in mid-ribs and mesophyll, resulting in the establishment of successful leaf defense.
Institute of Biology, Pedagogical University, Podchorążych 2, 30-084 Kraków, Poland.
Michał
M
Nosek
Institute of Environmental Science, Jagiellonian University, Gronostajowa 7a, 30-387 Kraków, Poland; Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland.
Piotr
P
Rozpądek
Institute of Biology, Pedagogical University, Podchorążych 2, 30-084 Kraków, Poland.
Andrzej
A
Kornaś
Department of Plant Physiology and Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Łódź, Poland.
Elżbieta
E
Kuźniak
Julius Kühn Institute, Federal Research Institute for Cultivated Plants (JKI), Heinrichstraße 243, D-64287 Darmstadt, Germany.
Annegret
A
Schmitt
Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland; Małopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7a, 30-387 Kraków, Poland.
Zbigniew
Z
Miszalski
D020171:Botrytis / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D035723:Mesembryanthemum / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology*; D058503:Mesophyll Cells / Q000378:metabolism / Q000382:microbiology; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism
D010940:Plant Proteins
Botrytis cinerea; C(3); CAM; Mesembryanthemum crystallinum; Vascular bundles