Fig 1.
Developmental effects of auxin in the M. polymorpha thallus.
(A) 10-day-old wild-type gemmaling with four apical notches and well developed air pores. (B) 10-day-old wild-type gemmae grown on 10 μM NAA. (C) Dorsal epidermis of 15-day-old wild-type thallus. (D) Dorsal epidermis of 15-day-old wild-type thallus, transferred on day 6 to 10 μM 2,4-D with abnormal air pores. (E) 18-day-old wild-type thallus with three gemmae cups. (F) 23-day-old wild-type thallus transferred at day 16 to 10 μM NAA with elongated gemmae cup. (G) Wild-type mature gemmae cup. (H) Wild-type mature gemmae cup from 17-day-old plant, transferred at day 12 to 10 μM 2,4-D. (I) Wild-type mature gemmae cup with gemmae inside. (J) Wild-type mature gemmae cup from a plant grown on 100 μM L-Kyn. (K) Ventral side of wild-type thallus grown on mock media. (L) Ventral side of wild-type thallus grown on 100 μM L-Kyn; a decrease in rhizoid number exposes ventral scales. (M) Mature thallus showing a thallus lobe separating two recently bifurcated apical notches. (N) Mature thallus of plants transferred on day 7 to 100 μM L-Kyn, showing a smaller lobe spacing apical notches and fused gemmae cup primordia (arrowhead). (O) Strong proEF1:iaaL lines are composed of an undifferentiated mass of cells that fail to establish a clear dorsiventrality. (P) Close up view of proEF1:iaaL line shows a mass of undifferentiated cells although rhizoids are able to differentiate. (Q) Expression pattern of proMpSHI in mature thallus with staining in the vicinity of the apical cell. (R) Different degrees of gemmae cup fusion observed in 100 μM L-Kyn treated plants. (S) proMpSHI:iaaL plants show an irregular zig-zag arrangement of gemmae cups that are in close proximity to each other. Scale bars in A, B, E, F, G, H, J, K, L, O, R and S = 1 mm; C, D and P = 0.6 mm; I = 0.5 mm; M = 1.2 mm; N = 0.75 mm; Q = 0.2 mm. Asterisk, apical notch; a, air pores; gc, gemma cups; g, gemmae.
Fig 2.
MpIAA represses auxin signaling in M. polymorpha.
(A) RLM RACE of amiRMpIAA expressing lines. Left panel shows gel electrophoresis of RLM-RACE products. Right panel shows direct sequencing of the 633bp RLM-RACE product from amiRMpIAA9. Sequencing detected the expected cleavage of MpIAA between bases 10/11 of both miR sequences. (B) Auxin hypersensitivity in knock-down MpIAA lines at both the sporeling and adult stages. At the sporeling stage, proEF1:amiRMpIAA7 sporelings grown on 5μM 2,4-D from germination have severely affected area compared to G418Res controls. In the adult stage plants were grown for 16 days on B5 media prior to treatment with 2,4-D. proEF1:amiRMpIAA9 treated with 7.5μM 2,4-D for ten days form ectopic rhizoids compared to HygRes controls. In all panels, each of the plants is an independent transformant. Scale Bars = 1 cm.