Fig 1.
Research scheme for plant signaling from mature to young leaves.
Lesion formation in cat2 typically starts from older leaves. To dissect the role of leaf age on PCD regulation, leaves were separated into the classes old (with visual lesions), mature (fully developed without lesions) and young (developing). Several positive and negative regulators of cat2 cell death were previously identified ([24]; see also Table 1), and the most informative of these were used to gain insights into the regulation of expression of cell death marker genes.
Fig 2.
Expression of PCD marker genes in LMMs cpr5, flu, mkk1 mkk2 and ssi2-1.
Expression of FMO1, PLA2A, WRKY75, WRKY40 and GLTP as visualized by investigating selected mutants in Genevestigator using the Perturbations tool. Green indicates decreased expression and red increased expression.
Table 1.
Summary of cat2 double mutant cell death phenotypes.
The cat2 single mutant develops extensive cell death when grown on soil in 12/12h light dark conditions [24]. The double mutants were used for gene expression analysis to determine potential signaling pathways involved in gene regulation during PCD.
Fig 3.
PCD marker gene expression related to hormone, ROS and pathogen response.
Expression of FMO1, PLA2A, WRKY75, WRKY40 and GLTP as visualized by investigating selected hormone, pathogen and ROS treatments in Genevestigator using the Perturbations tool. Green indicates decreased expression and red increased expression. Plant age is indicated in parenthesis.
Fig 4.
Marker gene expression in Col-0 and positive regulators of PCD in three leaf age classes.
Mutants were divided into functional classes based on their primary function in defense signaling. Letters indicate differences between leaf age classes (p<0.05; n = 3) and asterisks differences relative to Col-0 at the corresponding leaf age. Leaves divided into age classes are: young (white boxes), mature (grey) and old (green). The values represent the mean (box) and standard error (bar).
Fig 5.
Marker gene expression in cat2 and in double mutants defective in hormone signaling pathways or TFs.
Letters indicate differences between leaf age classes (p<0.05; n = 3) and asteriks show significant differences relative to cat2 at the corresponding leaf age. The values represent the mean (box) and standard error (bar).
Fig 6.
Marker gene expression in two LMMs dnd1 and cat2.
Letters indicate differences between leaf age classes (p<0.05; n = 3) and asteriks show significant differences relative to dnd1 at the corresponding leaf age. The values represent the mean (box) and standard error (bar).
Fig 7.
The expression of SA marker genes in Col-0, cat2, axr1 and cat2 axr1.
Letters indicate differences between leaf age classes (p<0.05; n = 3) and asterisks significant differences relative to cat2 at the corresponding leaf age. The values represent the mean (box) and standard error (bar).