Auxin homeostasis in <i>Bdtar2l^hypo</i> roots and its relation to the ethylene pathway.

<p>(<i>A</i>) Free auxin (IAA) content in wild type and <i>Bdtar2l^hypo</i> root segments at 4 dag. The root tip comprised the terminal 8 mm of the roots, the elongated parts all above this. (<i>B</i>) Expression levels of the homologs of various genes encoding rate limiting enzymes in alternative auxin biosynthesis pathways in wild type and <i>Bdtar2l^hypo</i> roots at 4 dag. (<i>C</i>) Expression levels of <i>YUCCA</i> homologs in wild type and <i>Bdtar2l^hypo</i> roots at 4 dag. (<i>D</i>) Expression levels of <i>BdTAR1L</i> and <i>BdTAR2L</i> in wild type at 3 dag and after 3 h of ACC treatment. (<i>E</i>) Expression levels of <i>YUCCA</i> homologs in wild type at 3 dag and after 3 h of ACC treatment. All expression levels were determined by qPCR and normalized with respect to the housekeeping gene, <i>BdUBC18</i>; differences as compared to wild type or mock are not significant unless indicated otherwise; error bars indicate standard error; * = p<0.05; ** = p<0.01; *** = p<0.001.</p

Phenotypes of the <i>Bdtar2l^qnull</i> mutant in comparison to its wild type background, Bd21-3.

<p>(<i>A</i>) Relative expression level of <i>BdTAR2L</i> in different genotypes at 4 dag as determined by qPCR and normalized with respect to the housekeeping gene, <i>BdUBC18</i>. (<i>B–C</i>) Root elongation in wild type and <i>Bdtar2l^qnull</i> mutants, assayed at 4 dag. (<i>D</i>) Representative Nomarski optics images of mature root portions. Arrowheads point out top and bottom of individual cells in a cortex layer; (<i>E</i>) Quantification of mature cortex cell length at 4 dag. (<i>F</i>) Representative microscopy images of root hairs at 4 dag. (<i>G</i>) Representative light microscopy images of transverse sections across the mature root. (<i>H–I</i>) Quantification of total transverse area and stele area in sections from mature roots. (<i>J</i>) Relative seminal root length in <i>Bdtar2l^qnull</i> mutants during root growth progression. (<i>K</i>) Progressive breakdown of root meristem as indicated by shrinkage of the meristematic zone. (<i>L</i>) Seedling shoot length at 4 dag. (<i>M</i>) Adult shoots. Size bars are 1 cm (<i>B, M</i>) or 100 µm (<i>D,F,G</i>); differences as compared to wild type or mock are not significant unless indicated otherwise; error bars indicate standard error; * = p<0.05; *** = p<0.001.</p

Isolation of the <i>Bdtar2l^hypo</i> mutant and characterization of macroscopic phenotypes.

<p>(<i>A</i>) Four-day-old tissue culture grown seedlings of wild type (accession Bd21), an unrelated control transformant (control) (the unrelated transformant line was included in all our assays to control for any tissue culture regeneration effects) and the transgenic line segregating the <i>Bdtar2l^hypo</i> mutation. (<i>B</i>) Seminal root length quantification of the different genotypes at 4 days after germination (dag). (<i>C</i>) Schematic presentation of the <i>BdTAR2L</i> gene and the location of the T-DNA insertion in the <i>Bdtar2l^hypo</i> mutant. (<i>D–E</i>) Relative expression level of <i>BdTAR2L</i> in different genotypes at 4 dag as determined by qPCR and normalized with respect to the housekeeping gene, <i>BdUBC18</i>. (<i>F</i>) Root elongation in wild type, control and homozygous <i>Bdtar2l^hypo</i> mutants, assayed at 4 dag. (<i>G–H</i>) Quantification of seedling phenotypes at 4 dag. (<i>I</i>) Leaf number at 18 dag. (<i>J–L</i>) Different size parameters of the 5^th leaf of plants, assayed at 18 dag. (<i>M</i>) Representative image of adult plants at 18 dag. Size bars are 1 cm; differences as compared to wild type are not significant unless indicated otherwise; error bars indicate standard error; * = p<0.05; ** = p<0.01; *** = p<0.001.</p

Effect of L-kynerunine (L-kyn) treatment on root elongation of different genotypes.

<p>(<i>A</i>) Representative images of 4-day-old seedlings, transferred onto media with indicated L-kyn concentration at 2 dag. (<i>B</i>) Quantification of root length after 2 days of indicated L-kyn treatment. (<i>C</i>) Representative Nomarski optics images of mature root portions formed during indicated L-kyn treatment. Arrowheads point out top and bottom of individual cells in the 3^rd cortex layer; (<i>D</i>) Quantification of mature cortex cell length after 2 days of indicated L-kyn treatment. (<i>E–F</i>) Relative root elongation of indicated mutants and their respective wild type backgrounds after 2 days of indicated 5-methyl-tryptophan treatment. Size bars are 1 cm (<i>A</i>) or 100 µm (<i>C</i>); differences as compared to wild type or mock are not significant unless indicated otherwise; error bars indicate standard error; * = p<0.05; ** = p<0.01; *** = p<0.001.</p

A schematic overview of the regulation of tryptophan-dependent auxin (indole-3-acetic acid) biosynthesis via indole-3-pyruvic acid (IPA) by ethylene action in Arabidopsis (<i>A</i>) and Brachypodium (<i>B</i>).

<p>A schematic overview of the regulation of tryptophan-dependent auxin (indole-3-acetic acid) biosynthesis via indole-3-pyruvic acid (IPA) by ethylene action in Arabidopsis (<i>A</i>) and Brachypodium (<i>B</i>).</p