Rust Infection of Black Poplar Trees Reduces Photosynthesis but Does Not Affect Isoprene Biosynthesis or Emission

Abstract

Poplar (Populus spp.) trees are widely distributed and play an important role in ecological communities and in forestry. Moreover, by releasing high amounts of isoprene, these trees impact global atmospheric chemistry. One of the most devastating diseases for poplar is leaf rust, caused by fungi of the genus Melampsora. Despite the wide distribution of these biotrophic pathogens, very little is known about their effects on isoprene biosynthesis and emission. We therefore infected black poplar (P. nigra) trees with the rust fungus M. larici-populina and monitored isoprene emission and other physiological parameters over the course of infection to determine the underlying mechanisms. We found an immediate and persistent decrease in photosynthesis during infection, presumably caused by decreased stomatal conductance mediated by increased ABA levels. At the same time, isoprene emission remained stable during the time course of infection, consistent with the stability of its biosynthesis. There was no detectable change in the levels of intermediates or gene transcripts of the methylerythritol 4-phosphate (MEP) pathway in infected compared to control leaves. Rust infection thus does not affect isoprene emission, but may still influence the atmosphere via decreased fixation of CO2.

High-resolution methylome analysis in the clonalPopulus nigracv. ‘Italica’ reveals environmentally sensitive hotspots and drought-responsive TE superfamilies

“…Zhang et al, 2018), however little information is available about woody plants. It is known that SA treatment, rust infection, and caterpillar attack increase the levels of SA, JA and ABA in the affected poplar leaves (Clavijo Mccormick et al, 2014; Eberl, Hammerbacher, et al, 2018; Eberl, Perreca, et al, 2018; Li et al, 2018; Ullah et al, 2019). Moreover, SA can be transported from infected to uninfected sites to induce systemic acquired resistance (SAR) (Li et al, 2018).…”

Poplar protease inhibitor expression differs in an herbivore specific manner

“…Sequencing was done at the Max Planck-Genome-Center (Köln, Germany) on a HiSeq 2500 (Illumina, San Diego, CA, USA) with 9 Mio reads per sample. Detailed information on quality control measures, the assembly of the de novo transcriptome and the annotation can be found in Eberl et al [12], but the most relevant information will be summarized here. The annotation was done using, among others, BLAST, Gene Ontology (GO) and InterPro terms (InterProScan, EBI).…”

Effect of Drought on the Methylerythritol 4-Phosphate (MEP) Pathway in the Isoprene Emitting Conifer Picea glauca

“…The extent to which each of the two pathways contributes to the total DMADP/IDP pool under various conditions has not been completely elucidated. Eberl et al (2018) suggested a contribution to the total DMADP/IDP intermediate pool size from the MVA pathway, under fungus infestation in poplar leaves. Dudareva et al (2005) showed that the MEP pathway provides IDP precursors for both plastidial monoterpene and cytosolic sesquiterpenes synthesis in snapdragon flowers and pointed out the possibility of a cross talk between the two pathways.…”