Allele-Specific Interactions Between ttg and gl1 During Trichome Development in Arabidopsis thaliana

Abstract

Trichome development in Arabidopsis thaliana is a well-characterized model for the study of plant cell differentiation. Two genes that play an essential role in the initiation of trichome development are GL1 and TTG. Mutations in either gene prevent the initiation of most trichomes. The GL1 gene encodes a myb-related transcription factor. Mutations in TTG are pleiotropic, affecting anthocyanins, root hairs, and seed coat mucilage in addition to trichomes. Six ttg alleles were examined and shown to form a hypomorphic series. The severity of all aspects of the ttg phenotype varied in parallel in this allelic series. The weakest allele, ttg-10, causes frequent clusters of adjacent trichomes, suggesting a role for TTG in inhibiting neighboring cells from choosing the trichome fate. This allele results from a mutation in the 5′-untranslated region of ttg and creates an out-of-frame upstream AUG codon. The ttg-10 allele shows several unusual genetic interactions with the weak hypomorphic gl1-2 allele, including intergenic noncomplementation and a synthetic glabrous phenotype. These interactions are specific for the gl1-2 allele. The implication of these results for current models of trichome development is discussed.

Gene Regulatory Network topology mediates the role of diffusible components in cellular patterns: the root epidermis of Arabidopsis thaliana as a study system

“…Transverse sections from the mature portion of the root show that the number of epidermal and cortical cells in the ttg1 mutant roots is indistinguishable from that of the WT. This evidence indicates that the ttg1 mutation alters the positional control of root-hair cell differentiation, but it does not affect root-hair formation [42,67]. If we analyze the results reported for the quantification of the number of hairs and non-hairs in the N and H positions in the ttg1-1 mutant, we can see that the results are very similar with respect to those obtained through the simulations.…”

Cytosolic HSP90 associates with and modulates the Arabidopsis RPM1 disease resistance protein

“…This often indicates that the two genes act together, that the protein products physically interact or are part of the same protein complex, or that half the wild‐type dose of the two, in combination, is insufficient for wild‐type function (e.g. Belanger et al ., 1994; Larkin et al ., 1999).…”

Transcriptome differential display of a drought‐tolerant early flowering spineless mutant of safflower (Carthamus tinctorius) and identification of candidate genes

“…We assume that formation of spines on leaf and bract margins may be related to reduplication cell cycles, and the KAK can be associated to spine formation. RTN (reduced trichome number) affects the initiation of trichomes (Larkin et al., 1999), and TBL (TRICHOME BIREFRINGENCE) and its homolog AT5G01360 encode plant‐specific DUF231 proteins which are required for cellulose biosynthesis in Arabidopsis (Bischoff et al., 2010). Both the genes can be candidates for spininess in safflower.…”