Article Figures & Data
Figures
- Fig. 1.
Floral phenotype of the homeotic mutantmtapetala and molecular evidence of artificial hybridization. a and b, Flowers of a similar developmental stage from genotypes mtapetala (a) and A17 (b). Numbers refer to floral whorl number beginning with the outermost whorl that form in wild-type flowers: 1, sepals; 2, petals; 3, stamens; and 4, carpels. c, RAPD analysis of progeny of a cross into mtapetala confirms cross-hybridization. Lane M, M r marker; 1, parental ecotype A17 (parent 1); 2, ecotype A48 (parent 2); 3 to 8, six independent F1 progeny. Primer 1, “gaacggactc”; primer 2, “tggaccggtg.” Bar = 1 mm.
- Fig. 2.
Morphology of floral organs in wild-type A17 and in floral homeotic mutant mtapetala. Scanning electron micrographs of whorl 1/sepal (a and b); whorl 2/petal (c and d); whorl 3/stamen (e and f); and whorl 4/carpel (g and h). Whorl 2 in thetap mutant is a partial transformation of whorl 2 identity and consists of cellular morphologies that are diagnostic of whorl 1/sepals (asterisk), and whorl 2/petals (arrowheads) of wild-type flowers. Whorl 3 in tap is a partial transformation of organ shape into a club shaped structure (Fig. 2f), and these organs are devoid of the sharp transition in cell morphologies found in wild-type whorl 3 (Fig. 2e). Moreover, whorl 3 in tap contains stigmatic papillae (arrowheads, Fig. 3f, and inset) that occur at the stigma/style junction in whorl 4 of wild type andtap (arrowheads, Fig. 2, g and h, respectively). Bars in a through d = 25 μm; bars in e through h = 100 μm; bar in f inset = 10 μm.
- Fig. 3.
Phenotypic analysis of shoot meristem formation in mutant palmyra. a and b, Shoot systems of 25-d-old seedlings of genotypes palmyra (a) and wild type (b). c and d, Morphological analysis of shoot meristem of mature embryos from palmyra (c) and wild type (d). The shoot meristem is undifferentiated in palmyra with no organ primordia evident (arrowhead, c). In comparison, wild-type shoot meristem is differentiated and contains leaf primordia (arrowhead, d). e and f, Adventitious shoot formation in palmyra from flank of stalk-like structure (e) and base of cotyledons (f) is marked by an arrow. c, Cotyledon; u, unifoliate leaf; t, trifoliate leaf petiole; s, stem-like shoot. Bars in a, b, e, and f = 5 mm; bars in c and d = 100 μm.
- Fig. 4.
Phenotypic analysis of pigmentation mutantspeckle. a, Light micrograph of aeroponically grownspeckle roots. b and c, Transverse sections through roots of wild type (c) and speckle (d) prior to inoculation withRhizobium. d and e, Light micrographs of stems from wild type (d) and speckle (e). Pigmented cells are sporadically distributed in the epidermis and cortex of speckle roots (arrows, Fig. 5, a and c) and stems (arrows, Fig. 5e). x, Xylem; e, epidermis; c, cortex. Bars in a = 250 μm; bars in c and d = 50 μm; bars in e and f = 1 mm.
- Fig. 5.
Pigmentation patterns on both the adaxial and abaxial leaf surfaces distinguish ecotypes A17 and A20. Typical leaf pigmentation found on ecotype A17 (a) and (c), and ecotype A20 (b) and (d). Adaxial leaf surfaces (a) and (b); abaxial leaf surfaces (c) and (d). Arrowheads denote the adaxial leaf spot of A17 (a), and the abaxial freckles of A20 (d). Bar = 1 cm.
- Fig. 6.
Analysis of mtgp, a MADS-domain containing gene expressed in developing M. truncatulaflowers. a, Phylogenetic analysis of mtgp with functionally characterized class B floral homeotic genes, places mtgpwithin the ap3/def/gp subgroup, and distinct from thepi/glo subgroup of class B floral homeotic MADS-box genes. b, Alignment of deduced amino acid sequences of mtgp with class B MADS-domain containing genes nmh7 of M. sativa, and ap3 and pi of Arabidopsis. For clarity, only sequences corresponding to the partial mtgpcDNA are shown.
Tables
EMS Seedling Survival1-a Fertile Plants Seed/Pod1-b Seed Weight1-b Arrested Embryos1-c % mg 0 69 ± 5.9 100 9.7 ± 0.07 3.8 ± 0.07 0 0.025 68 ± 11.9 100 8.6 ± 0.38 3.5 ± 0.12 1.1 ± 0.2 (6.7 ± 2.8) 0.075 64 ± 5.7 >95 4.6 ± 0.47 4.1 ± 0.03 8.4 ± 1.8 (27 ± 10.2) 0.150 71 ± 13.9 >95 2.3 ± 0.15 3.7 ± 0.20 21.0 ± 2.2 (42.0 ± 2.6) 0.225 40 ± 6.4 <2 nd1-d nd nd 0.675 0 0 nd nd nd 2.025 0 0 nd nd nd -
↵F1-a Seedling survival was scored as the emergence of the first trifoliate.
-
↵F1-b Seed/pod and seed wt were scored individually on >120 randomly selected pod for each EMS treatment.
-
↵F1-c The frequency of arrested embryos was assessed in four groups of =30 seed pod each. Data are expressed both as the percentage of seed pod containing at least one arrested embryo and as the percentage of total seed analyzed (in parentheses).
-
↵F1-d nd, Values not determined due the absence of fertile individuals.
-
- Table II.
Frequency of selected seed and seedling phenotypes in M2 of 0.15% EMS-treated seed
Seed Phenotypes Seedling Pigmentation2-c Tan seed coat2-a Stay green2-b Albino Chlorotic Pale green Total seedling pigmentation 17.5 ± 3.2 0.20 ± 0.03 0.4 ± 0.7 3.5 ± 1.8 2.0 ± 1.7 5.8 ± 3.1 -
↵F2-a Tan seed coat phenotypes were scored on seed obtained from individual pods representing four groups of >30 pod each group. Data are expressed as the percentage of seed pod containing at least one scorable phenotype.
-
↵F2-b Stay green phenotypes were scored on three samples of =4,000 seed each.
-
↵F2-c Pigmentation phenotypes were scored on 7-d-old aeroponically grown seedlings. A total of 17 seed pools were analyzed, each derived from 40 randomly collected seed pods, with an average of 70 ± 9.4 germinated individuals/pool.
-
Cross Total Progeny Analyzed Observed χ2Value P Value No. of Genes and Inferred Nature of Dominance Wild type Mutant tap × A17 134 102 32 0.090 >0.750 1 Gene, recessive plm × A17 187 145 42 0.644 >0.400 1 Gene, recessive spk × A17 141 114 27 2.577 >0.100 1 Gene, recessive albino × A203-a 495 458 37 1.267 >0.250 2 Genes, recessive3-a -
↵F3-a Tested with F2 ratios of 15:1, wild type:mutant expected for duplicate dominant epistasis.
-
