Heterologous myb genes distinct fromGL1enhance trichome production when overexpressed inNicotiana tabacum

Abstract

Myb-class transcription factors implicated in cell shape regulation were overexpressed in Arabidopsis thaliana and Nicotiana tabacum in an attempt to assess the extent to which cellular differentiation programs might be shared between these distantly related plants. GLABROUS 1, a myb gene required for trichome development in Arabidopsis, did not alter the trichome phenotype of the tobacco plants in which it was overexpressed. MIXTA, which in Antirrhinum majus is reported to regulate certain aspects of floral papillae development, did not complement the glabrous 1 mutant of Arabidopsis. However, 35S:MIXTA transformants of N. tabacum displayed various developmental abnormalities, most strikingly production of supernumerary trichomes on cotyledons, leaves and stems. In addition, floral papillae were converted to multicellular trichomes. CotMYBA, a myb gene which is expressed in Gossypium hirsutum ovules and has some homology to MIXTA, was also overexpressed in the two species. A similar but distinct syndrome of abnormalities, including the production of cotyledonary trichomes, was observed in 35S:CotMYBA tobacco transformants. However, CotMYBA did not alter trichome production in Arabidopsis. These results suggest that the trichomes of Arabidopsis and Nicotiana are merely analogous structures, and that the myb genes regulating their differentiation are specific and separate.

Characterisation of the Mentha canadensis R2R3-MYB transcription factor gene McMIXTA and its involvement in peltate glandular trichome development

“…However, different types of trichomes have different transcriptional regulatory patterns. For example, the MIXTA gene in A. majus promotes the development of multicellular glandular trichomes in N. benthamiana , but has no effect on unicellular trichomes in Arabidopsis [ 44 ]. In contrast, Arabidopsis AtMYB16 regulates the development of unicellular trichomes but has no effect on multicellular trichomes [ 39 ].…”

Overexpression of CsMIXTA, a Transcription Factor from Cannabis sativa, Increases Glandular Trichome Density in Tobacco Leaves

“…The heterologous overexpression of CsMIXTA in tobacco has shown a significant impact on trichome development with increased density, enlarged size and more branching ( Figure 4 ). The overexpression of CsMIXTA in tobacco showed more distinct trichome phenotypes than that of AmMIXTA overexpression [ 14 , 23 ]. The overexpression of known MIXTA or MIXTA-like genes did not show a similar glandular trichome phenotype caused by overexpression of CsMIXTA , indicating that CsMIXTA may have unique functions in glandular trichome morphogenesis in cannabis.…”

Molecular Mechanisms of Plant Trichome Development

“…Based on the study of the hair development process in Arabidopsis , we divided the development of Arabidopsis trichomes into three stages: fate determination and initiation, trichome branching, and trichome elongation and maturation (reviewed by Payne et al, 1999 ; see also Hülskamp, 2004 ; Schellmann and Hülskamp, 2005 ). Morphogenesis can be divided into six stages, beginning which the trichome cell expanding rapidly relative to the surrounding normal epidermal cells and ending with a circle of trichome-supporting cells surrounding the trichome ( Szymanski and Marks, 1998 ).…”