Transparent testa

Table 6.1 Abbreviations BAN, BANYULS bHLH, basic helix-loop-helix CHS, chalcone synthase CHI, chalcone isomerase DFR, dihydroflavonol reductase F3H, flavonol 3-hydroxylase F3 H, flavonoid 3 -hydroxylase FLS, flavonol synthase icx, increased chalcone synthase expression LDOX, leucoanthocyanidin dioxygenase LCR, leucoanthocyanidin reductase MATE, multidrug and toxic compound extrusion NR, not yet reported tt, transparent testa ttg, transparent testa glabrous the WD40 and WRKY transcription factors are named for conserved amino acid sequences within these proteins. PC = personal communication.

SHIRLEY, B.W., HANLEY, S., GOODMAN, H.M., Effects of ionizing radiation on a plant genome analysis of two Arabidopsis transparent testa mutations, Plant Cell, 1992, 4, 333-347. 

WALKER, A.R., DAVISON, P.A., BOLOGNESI-WINFIELD, A.C., JAMES, C.M., SRINIVASAN, N., BLUNDELL, T.L., ESCH, J.J., MARKS, M.D., GRAY, J.C., The TRANSPARENT TESTA GLABRA1 locus, which regulates trichome differentiation and anthocyanin biosynthesis in Arabidopsis, encodes a WD40 repeat protein, Plant Cell,... 

FOCKS, N., SAGASSER, M., WEISSHAAR, B., BENNING, C, Characterization of ttl5, a novel transparent testa mutant of Arabidopsis thaliana (L.) Heynh, Planta, 1999, 208, 352-357. 

In order to compare mutation frequency induced by 220-MeV C ions with that by low-LET radiation (electrons), Arabidopsis visible phenotype loci were chosen as follows transparent testa tt) whose seed coat is transparent because of lack of pigment glaborous gl), which have no hair on their leaves and stems and long hypocotyl hy) whose hypocotyl is longer than that of the wild type in the light condition. Mutation frequencies of tt, gl, and hy induced by carbon ions were 8- to 34-fold higher than those by electrons (Table 2). In this study, irradiation doses for the induction of mutation were determined from the RBE of carbon ions compared with that of electrons on the survival of plants, which was approximately 5. Both doses are at three-quarters of the shoulder dose of each survival curve [104]. 

Debeaujon, I. et al.. The TRANSPARENT TESTA 12 gene of Arabidopsis encodes a multidrug secondary transporter-like protein required for flavonoid sequestration in vacuoles of the seed coat endothelium. Plant Cell, 13, 853, 2001. 

Kitamura, S., Shikazono, N., and Tanaka, A., TRANSPARENT TESTA 19 is involved in the accumulation of both anthocyanins and proanthocyanidins in Arabidopsis. Plant J., 37, 104, 2004. 

Carey, C.C. et al.. Mutations in the pale aleurone color 1 regulatory gene of the Zea mays anthocyanin pathway have distinct phenotypes relative to the functionally similar TRANSPARENT TESTA GLABRAl gene in Arabidopsis thaliana. Plant Cell, 16, 450, 2004. 

Walker, A.R. et al.. The TRANSPARENT TESTA GLABRAl locus, which regulates trichome differentiation and anthocyanin biosynthesis in Arabidopsis, encodes a WD40 repeat protein. Plant Cell, 11, 1337, 1999. 

Johnson, C.S., Kolevski, B., and Smyth, D.R., TRANSPARENT TESTA GLABRA2, a trichome and seed coat development gene of Arabidopsis, encodes a WRKY transcription factor. Plant Cell, 14, 1359, 2002. 

Sagasser, M. et al., A. thaliana TRANSPARENT TESTA 1 is involved in seed coat development and defines the WIP subfamily of plant zinc finger proteins. Genes Dev., 16, 138, 2002. 

Peer WA, Brown DE, Tague BW, Muday GK, Taiz L, Murphy AS. 2001. Flavonoid accumulation patterns of transparent testa mutants of Arabidopsis. Plant Physiol 126 536-548. 

Arahidopsis has become the model system of choice in which to study many aspects of plant growth, development, and metabolism, including the biosynthesis of phenylpropanoid natural products. This is, in part, because Arabidopsis accumulates two classes of phenylpropanoid end products that are good targets for mutant screens. For example, many screens have identified mutants defective in fiavonoid biosynthesis. Defects in this pathway in Arahidopsis lead to transparent testa (tt) and transparent testa glabrous (ttg) phenot3Tjes that result from decreases in the condensed tannins found in the seed coat. These mutants have already been exhaustively reviewed, and hence will not be covered here. 

It remains to be shown which ABC transporters facilitate directly energized glucoside transport. However, the recent identification of the first membrane protein related to the transport of phenolic compounds based on the analysis of the Arabidopsis transparent testa (tt)12 mutant provides evidence that the phenolic glucoside/ ff-antiporters are likely to be members of the... 

Peer WA, Brown DE, Tague BW, etal. (2001) Flavonoid accumulation patterns of transparent testa mutants of Arabidopsis. Plant Physiol 126 536-548 Peer WA, Bandyopadhyay A, Blakeslee JJ, et al. (2004) Variation in expression and protein localization of the PIN family of auxin efflux facilitator proteins in flavonoid mutants with altered auxin transport in Arabidopsis thaliana. Plant Cell 16 1898-1911... 

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